NextEra Energy to Build Its First Green Hydrogen Plant in Florida

The emerging green hydrogen market could open new opportunities for NextEra to use its renewable power.

 

Largest U.S. renewables generator “really excited” about green hydrogen, reveals plans for $65 million pilot plant for Florida Power & Light.

NextEra Energy is closing its last coal-fired power unit and investing in its first green hydrogen facility.

Through its Florida Power & Light utility, NextEra will propose a $65 million pilot in the Sunshine State that will use a 20-megawatt electrolyzer to produce 100 percent green hydrogen from solar power, the company revealed on Friday.

The project, which could be online by 2023 if it receives approval from state regulators, would represent the first step into green hydrogen for NextEra Energy, by far the largest developer and operator of wind, solar and battery plants in North America.

“We’re really excited about hydrogen, in particular when we think about getting not to a net-zero emissions profile but actually to a zero-emissions carbon profile,” NextEra Energy CFO Rebecca Kujawa said on Friday’s earnings call.

“When we looked at this five or 10 years ago and thought about what it would take to get to true zero emissions, we were worried it was extraordinarily expensive for customers,” Kujawa said.

“What makes us really excited about hydrogen — particularly in the 2030 and beyond timeframe — is the potential to supplement a significant deployment of renewables [and energy storage]. That last amount of emissions you’d take out of the system to get down to zero could be most economically served by hydrogen.”

Green hydrogen plans taking off around the world

Although still in its infancy as a market, the concept of green hydrogen is rapidly catching on globally as a potentially viable way to fully decarbonize energy systems, taking them beyond where simple renewable power generation alone can go even at very high penetrations.

The green hydrogen produced by Florida Power & Light’s electrolyzers would be used to replace a portion of the natural gas that’s consumed by the turbines at FPL’s existing 1.75-gigawatt Okeechobee gas-fired plant, Kujawa said. The electricity will come from solar power that would otherwise have been “clipped,” or gone unused.

If the hydrogen economy scales up and green hydrogen becomes economic, Florida Power & Light would likely retrofit some of its gas facilities to run wholly or partially on hydrogen, Kujawa said.

Most of the vast quantities of hydrogen produced globally today use fossil fuels as a feedstock, generating substantial emissions in the process. In contrast, green hydrogen is made using renewables to power the electrolysis of water, throwing off no CO2 emissions.

Whichever way it’s produced, hydrogen can be used for a variety of purposes, from swapping in for natural gas in thermal power plants to powering fuel cells used to move cars and ships. (For more background, read GTM’s green hydrogen explainer.)

The EU recently set a target of installing 40 gigawatts of electrolyzers within its borders by 2030 to produce green hydrogen, as it charts a path to net-zero.

Air Products, the world’s leading hydrogen producer, recently announced a massive green hydrogen plant to be built in Saudi Arabia, powered by 4 gigawatts of wind and solar. And last week California-based fuel-cell maker Bloom Energy sent its shares soaring by announcing its launch into the commercial hydrogen market.

For NextEra, hydrogen represents not only an opportunity to help decarbonize its FPL utility but also a potential new market for the wind and solar power it generates across North America.

NextEra will start with the same “toe in the water” approach it took with solar and batteries, Kujawa said. “While the investments are expected to be small in the context of our overall capital program, we are excited about the technology’s long-term potential, which should further support future demand for low-cost renewables as well as accelerating the decarbonization of transportation fuel and industrial feedstocks.”

Florida Power & Light’s push into green hydrogen comes just weeks after the utility announced it plans to exit its 847-megawatt portion of Georgia’s Plant Scherer, the largest operating coal-fired power plant in the U.S. — and the last remaining coal unit in NextEra’s portfolio.

CEO Robo’s thoughts on the election

NextEra CEO Jim Robo was asked on the earnings call what impact could come from November’s election, with Joe Biden pledging to push policies aimed at fully decarbonizing the U.S. power supply by 2035 and the Democratic platform promising a near-term surge of renewables.

NextEra will be “positioned really well regardless of who wins in November,” Robo said.

“You can remember back close to four years ago … there was some turmoil around our stock when President Trump was elected. We’ve managed to completely be fine under this administration in terms of being able to continue to grow our renewable business, because you know: it’s all about economics.”

“The time for renewables is now and that kind of transcends politics, frankly,” Robo said. “Obviously, we watch [political outcomes] closely. We think good clean energy policy is important and the right policy for America in the future.”

Renewable to Clean Energy – Floating wind-to-hydrogen plan to heat millions of UK homes

Project aiming to deploy 4GW, £12bn ‘green hydrogen’ array in the North Sea is backed by UK government

Floating offshore wind turbines far out in the North Sea will convert seawater to ‘green’ hydrogen that will be pumped ashore and used to heat millions of homes, under an ambitious plan just awarded UK government funding.

Deployment of a 4GW floating wind farm in the early 2030s at an estimated cost of £12bn ($14.8bn) could be the first step in the eventual replacement of natural gas by hydrogen in the UK energy system, claimed Kevin Kinsella, director of the Dolphyn project for consultancy ERM.

ERM – which is working on Dolphyn with the Tractebel unit of French energy giant Engie and offshore specialist ODE – plans to integrate hydrogen production technology into a 10MW floating wind turbine platform, enabling each unit to import seawater, convert it to hydrogen and export the gas via a pipeline.

“If you had 30 of those in the North Sea you could replace the natural gas requirement for the whole country.”

Deployment of hundreds of the floating platforms would be able to tap into the excellent wind resources far out in the North Sea, way beyond the depths accessible to fixed-bottom foundations, Kinsella told Recharge, estimating that a 4GW floating wind farm could produce enough hydrogen to heat 1.5 million homes.

“If you had 30 of those in the North Sea you could totally replace the natural gas requirement for the whole country, and be totally self-sufficient with hydrogen,” said Kinsella.

ERM in August received £427,000 under a UK government support plan for promising hydrogen technologies. That will be used to develop a prototype unit for deployment off Scotland using a 2MW turbine from MHI Vestas and the WindFloat platform, designed by floating wind specialist Principle Power and already successfully tested off Portugal, Kinsella added.

It plans to have the 2MW prototype ready for a final investment decision by 2021, at which point ERM hopes a major energy player – “an Engie or a BP or a Total” – will back the project to take it forward to deployment by 2023, with a full-scale 10MW version in the water in 2026.

Will floating wind power help Big Oil crack its ‘Kinder Egg’?

Read more

The Dolphyn team is integrating into the floating turbine platform the systems needed for water intake, desalination and conversion of water to hydrogen via proton exchange membrane (PEM) technology.

The gas will then be exported under pressure via a flexible riser, before joining the output of other turbines to be pumped to shore via a trunkline. Kinsella said the project team is talking to a “major oil company” about repurposing an existing pipeline for hydrogen export.

The floating wind-to-hydrogen turbines would be completely independent of the power grid – a major contributor to cost reduction Kinsella, said. “Once you get a long way offshore it’s the electrical infrastructure that dominates the costs.” They will be equipped with an on-board energy storage unit to make them self-sufficient, with the ability to restart the turbine from a standstill.

Generating ‘green hydrogen’ – completely produced via renewables – competitively at scale is one of the big challenges before it can assume a key role in the energy transition. Pilot green hydrogen projects currently operate at five to ten-times the cost of ‘grey’ hydrogen, which is produced using fossil fuels but is by far the cheapest existing option.

However, research group BloombergNEF recently projected an 80% fall in the cost of green hydrogen by 2030, opening the way for its widespread use as a carbon-free fuel.

ERM’s projections suggest a full-scale floating wind farm deployed in 2032 – by which time 15MW turbines may be used – could produce hydrogen at £1.15/kg ($1.41/kg). “This is comparable with the projected wholesale UK price of natural gas,” Kinsella claimed.

Hydrogen: the green-energy problem solver

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Decarbonising heat and transport, as well as power supplies, are major challenges facing the UK as it seeks to become emissions ‘net-zero’ by 2050.

A 2018 report from the UK Committee on Climate Change said hydrogen could largely replace natural gas for heating into the 2030s, but questioned whether renewable generation could compete on cost with hydrogen produced using gas itself then subjected to carbon capture and storage.

Cost-effective method for hydrogen fuel production process discovered at U of A

Researchers at the U of A have designed nanoparticles that act as catalysts, making the process of water electrolysis more efficient. Credit: Jingyi Chen, Lauren Greenlee and Ryan Manso

 

Nanoparticles composed of nickel and iron have been found to be more effective and efficient than other, more costly materials when used as catalysts in the production of hydrogen fuel through water electrolysis.

The discovery was made by University of Arkansas researchers Jingyi Chen, associate professor of physical chemistry, and Lauren Greenlee, assistant professor of chemical engineering, as well as colleagues from Brookhaven National Lab and Argonne National Lab.

The researchers demonstrated that using nanocatalysts composed of nickel and iron increases the efficiency of water electrolysis, the process of breaking water atoms apart to produce hydrogen and oxygen and combining them with electrons to create hydrogen gas.

Chen and her colleagues discovered that when nanoparticles composed of an iron and nickel shell around a nickel core are applied to the process, they interact with the hydrogen and oxygen atoms to weaken the bonds, increasing the efficiency of the reaction by allowing the generation of oxygen more easily. Nickel and iron are also less expensive than other catalysts, which are made from scarce materials.

This marks a step toward making water electrolysis a more practical and affordable method for producing hydrogen fuel. Current methods of water electrolysis are too energy-intensive to be effective.

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Story Source:

Materials provided by University of Arkansas. Note: Content may be edited for style and length.

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Journal Reference:

1. Ryan H. Manso, Prashant Acharya, Shiqing Deng, Cameron C. Crane, Benjamin Reinhart, Sungsik Lee, Xiao Tong, Dmytro Nykypanchuk, Jing Zhu, Yimei Zhu, Lauren F. Greenlee, Jingyi Chen. Controlling the 3-D morphology of Ni–Fe-based nanocatalysts for the oxygen evolution reaction. Nanoscale, 2019; DOI: 10.1039/C8NR10138H

New Material For Splitting Water: Halide double Perovskites – “All the Right Properties” for creating Fuel Cells

Solar energy is clean and abundant, but when the sun isn’t shining, you must store the energy in batteries or through a process called photocatalysis. In photocatalytic water splitting, sunlight separates water into hydrogen and oxygen, which can then be recombined in a fuel cell to release energy. Now, a new class of materials — halide double perovskites — may have just the right properties to split water, according to research in Applied Physics Letters. In this image: Novel, lead-free double perovskites as potential photocatalysts for solar water splitting. Credit: George Volonakis

Now, a new class of materials — halide double perovskites — may have just the right properties to split water, according to a newly published paper in Applied Physics Letters, from AIP Publishing.

“If we can come up with a material that can be useful as a water-splitting photocatalyst, then it would be an enormous breakthrough,” said Feliciano Giustino, a co-author on the paper.

Researchers have experimented with many photocatalytic materials before, such as titanium dioxide (TiO2). While TiO2 can harness sunlight to split water, it’s inefficient because it doesn’t absorb visible light well. So far, no photocatalytic material for general water splitting has become commercially available.

Using supercomputers to calculate the quantum energy states of four halide double perovskites, George Volonakis and Giustino, both of the University of Oxford, found that Cs2BiAgCl6 and Cs2BiAgBr6 are promising photocatalytic materials because they absorb visible light much better than TiO2. They also generate electrons and holes (the positively charges absence of electrons) that have sufficient energy (or nearly ideal energies) to split water into hydrogen and oxygen.

Very few other materials have all these features at once, Giustino said. “We can’t say this will work for sure, but these compounds seem to have all the right properties.”

Giustino and his team originally discovered this type of perovskite while looking for materials to make solar cells. Over the last several years, perovskites have garnered interest as materials to boost the efficiency of silicon-based solar cells through tandem designs that integrate a perovskite cell directly onto a high-efficiency silicon cell, but they contain a small amount of lead. If they were used for energy harvesting in a solar farm, the lead could pose a potential environmental hazard.

In 2016, using computer simulations to identify alternative materials, the researchers found a new type of lead-free perovskite with potential for high-efficiency solar cells. The present paper shows these new materials may also split water. “These new double perovskites are not only promising as a complementary material for tandem solar cells, but they can also be promising in areas like photocatalysis,” Volonakis said.

Still, the new analysis is theoretical, assuming the compounds form perfect crystals. The next step, the authors said, is for experimentalists to see if the material works in the real world as well as predicted. In the meantime, the researchers are using their computational techniques to explore whether these double perovskites have properties useful for other applications like light detectors.

HyperSolar Announces Impressive Catalyst Stability for Solar Hydrogen Production

HyperSolar, Inc. the developer of a breakthrough technology to produce renewable hydrogen using sunlight and any source of water, announced today a significant improvement of its proprietary low-cost 3-dimensional oxygen catalyst.

The amount of hydrogen produced by water splitting is fundamentally limited by the slower oxygen half reaction.  Developing an efficient and stable oxygen catalyst is an important milestone in the Company’s effort to split water molecules for the production of renewable hydrogen. Recent catalyst optimization and performance testing by HyperSolar and the University of Iowa demonstrated its high efficiency oxygen catalyst working for over 190 hours, and still running without loss of efficiency.  In comparison to existing state-of-the-art photo-electrochemical technologies, this represents a significant advancement in terms of stability for catalysts made of entirely inexpensive earth abundant elements.

 

“Solar hydrogen production is challenged by the efficiency of the catalyst and the solar cell, and the risk of their instability in the harsh water conditions of photo-electrochemical reactions,” said Dr. Joun Lee, CTO of HyperSolar.  “This successful development of the 3D catalyst is an important milestone for achieving high hydrogen production efficiency for a long period of operation, which contributes to lowering the hydrogen production cost.  We are now in the process of further proving the stability of the 3D oxygen catalyst in a fully integrated solar-to-hydrogen device. We expect the device-level stability to be over 190 hours as well since the oxygen reaction is the primary limiter of device-level performance.”

This catalyst is designed for the Company’s first generation hydrogen system that uses commercially available and inexpensive amorphous triple junction silicon solar (a-Si) cells.

Tim Young, CEO of HyperSolar, commented, “Our goal with the a-Si system is to demonstrate at least 365 hours of stable hydrogen production under intensive operating conditions.  By doing so, we will have simulated one year of operating life of our technology, which we believe will make our technology commercially attractive in various hydrogen markets.  We believe that 1 year of stable operation can make conventional electrolyzer-based renewable hydrogen obsolete, and open up new markets due to our lower cost.”

About HyperSolar, Inc.
HyperSolar is developing a breakthrough, low cost technology to make renewable hydrogen using sunlight and any source of water, including seawater and wastewater. Unlike hydrocarbon fuels, such as oil, coal and natural gas, where carbon dioxide and other contaminants are released into the atmosphere when used, hydrogen fuel usage produces pure water as the only byproduct. By optimizing the science of water electrolysis at the nano-level, our low cost nanoparticles mimic photosynthesis to efficiently use sunlight to separate hydrogen from water, to produce environmentally friendly renewable hydrogen. Using our low cost method to produce renewable hydrogen, we intend to enable a world of distributed hydrogen production for renewable electricity and hydrogen fuel cell vehicles.  To learn more about HyperSolar, please visit our website at www.hypersolar.com.

 

A Step Closer for Clean Fuel: New Catalyst (Carbon-Based Nanocomposites) for Hydrogen Production

Carbon-based nanocomposite with embedded metal ions yields impressive performance as catalyst for electrolysis of water to generate hydrogen

A nanostructured composite material developed at UC Santa Cruz has shown impressive performance as a catalyst for the electrochemical splitting of water to produce hydrogen. An efficient, low-cost catalyst is essential for realizing the promise of hydrogen as a clean, environmentally friendly fuel.

Researchers led by Shaowei Chen, professor of chemistry and biochemistry at UC Santa Cruz, have been investigating the use of carbon-based nanostructured materials as catalysts for the reaction that generates hydrogen from water. In one recent study, they obtained good results by incorporating ruthenium ions into a sheet-like nanostructure composed of carbon nitride. Performance was further improved by combining the ruthenium-doped carbon nitride with graphene, a sheet-like form of carbon, to form a layered composite.

“The bonding chemistry of ruthenium with nitrogen in these nanostructured materials plays a key role in the high catalytic performance,” Chen said. “We also showed that the stability of the catalyst is very good.”

The new findings were published in ChemSusChem, a top journal covering sustainable chemistry and energy materials, and the paper is featured on the cover of the January 10 issue. First author Yi Peng, a graduate student in Chen’s lab, led the study and designed the cover image.

Hydrogen has long been attractive as a clean and renewable fuel. A hydrogen fuel cell powering an electric vehicle, for example, emits only water vapor. Currently, however, hydrogen production still depends heavily on fossil fuels (mostly using steam to extract it from natural gas). Finding a low-cost, efficient way to extract hydrogen from water through electrolysis would be a major breakthrough. Electricity from renewable sources such as solar and wind power, which can be intermittent and unreliable, could then be easily stored and distributed as hydrogen fuel.

Polymer electrolyte membrane (PEM) water electrolysis cell Figure 2B (right): Schematic of an electrochemical energy producer. PEM hydrogen /oxygen fuel …

Currently, the most efficient catalysts for the electrochemical reaction that generates hydrogen from water are based on platinum, which is scarce and expensive. Carbon-based materials have shown promise, but their performance has not come close to that of platinum-based catalysts.

In the new composite material developed by Chen’s lab, the ruthenium ions embedded in the carbon nitride nanosheets change the distribution of electrons in the matrix, creating more active sites for the binding of protons to generate hydrogen. Adding graphene to the structure further enhances the redistribution of electrons.

 

“The graphene forms a sandwich structure with the carbon nitride nanosheets and results in further redistribution of electrons. This gives us greater proton reduction efficiencies,” Chen said.

The electrocatalytic performance of the composite was comparable to that of commercial platinum catalysts, the authors reported. Chen noted, however, that researchers still have a long way to go to achieve cheap and efficient hydrogen production.

In addition to Peng and Chen, coauthors of the study include Wanzhang Pan and Jia-En Liu at UC Santa Cruz and Nan Wang at South China University of Technology. This work was supported by the National Science Foundation and the NASA-funded Merced Nanomaterials Center for Energy and Sensing.

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Story Source:

Materials provided by University of California – Santa Cruz. Original written by Tim Stephens. Note: Content may be edited for style and length.

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Journal Reference:

1. Yi Peng, Wanzhang Pan, Nan Wang, Jia-En Lu, Shaowei Chen. Ruthenium Ion-Complexed Graphitic Carbon Nitride Nanosheets Supported on Reduced Graphene Oxide as High-Performance Catalysts for Electrochemical Hydrogen Evolution. ChemSusChem, 2018; 11 (1): 130 DOI: 10.1002/cssc.201701880

Making Hydrogen Production Cheaper using New Ultra-Thin nano-material for splitting water

This is a water drop falling into water. Credit: Sarp Saydam/UNSW

UNSW Sydney chemists have invented a new, cheap catalyst for splitting water with an electrical current to efficiently produce clean hydrogen fuel.

The technology is based on the creation of ultrathin slices of porous metal-organic complex materials coated onto a foam electrode, which the researchers have unexpectedly shown is highly conductive of electricity and active for splitting water.

“Splitting water usually requires two different catalysts, but our catalyst can drive both of the reactions required to separate water into its two constituents, oxygen and hydrogen,” says study leader Associate Professor Chuan Zhao.

“Our fabrication method is simple and universal, so we can adapt it to produce ultrathin nanosheet arrays of a variety of these materials, called metal-organic frameworks.

“Compared to other water-splitting electro-catalysts reported to date, our catalyst is also among the most efficient,” he says.

The UNSW research by Zhao, Dr Sheng Chen and Dr Jingjing Duan is published in the journal Nature Communications.

Hydrogen is a very good carrier for renewable energy because it is abundant, generates zero emissions, and is much easier to store than other energy sources, like solar or wind energy.

But the cost of producing it by using electricity to split water is high, because the most efficient catalysts developed so far are often made with precious metals, like platinum, ruthenium and iridium.

The catalysts developed at UNSW are made of abundant, non-precious metals like nickel, iron and copper. They belong to a family of versatile porous materials called metal organic frameworks, which have a wide variety of other potential applications.

Until now, metal-organic frameworks were considered poor conductors and not very useful for electrochemical reactions. Conventionally, they are made in the form of bulk powders, with their catalytic sites deeply embedded inside the pores of the material, where it is difficult for the water to reach.

By creating nanometre-thick arrays of metal-organic frameworks, Zhao’s team was able to expose the pores and increase the surface area for electrical contact with the water.

“With nanoengineering, we made a unique metal-organic framework structure that solves the big problems of conductivity, and access to active sites,” says Zhao.

“It is ground-breaking. We were able to demonstrate that metal-organic frameworks can be highly conductive, challenging the common concept of these materials as inert electro-catalysts.”

Metal-organic frameworks have potential for a large range of applications, including fuel storage, drug delivery, and carbon capture. The UNSW team’s demonstration that they can also be highly conductive introduces a host of new applications for this class of material beyond electro-catalysis.

Explore further: Researchers report new, more efficient catalyst for water splitting

More information: Jingjing Duan et al, Ultrathin metal-organic framework array for efficient electrocatalytic water splitting, Nature Communications (2017). DOI: 10.1038/ncomms15341

Journal reference: Nature Communications

Provided by: University of New South Wales

 

 

How can we store solar energy for periods when the sun doesn’t shine? Researchers Turn to Known – Effective – Low Cost Method with a “Twist”

How can we store solar energy for period when the sun doesn’t shine?

 

One solution is to convert it into hydrogen through water electrolysis. The idea is to use the electrical current produced by a solar panel to ‘split’ water molecules into hydrogen and oxygen. Clean hydrogen can then be stored away for future use to produce electricity on demand, or even as a fuel.

 
But this is where things get complicated. Even though different hydrogen-production technologies have given us promising results in the lab, they are still too unstable or expensive and need to be further developed to use on a commercial and large scale.
The approach taken by EPFL and CSEM researchers is to combine components that have already proven effective in industry in order to develop a robust and effective system. Their prototype is made up of three interconnected, new-generation, crystalline silicon solar cells attached to an electrolysis system that does not rely on rare metals.

The device is able to convert solar energy into hydrogen at a rate of 14.2%, and has already been run for more than 100 hours straight under test conditions. In terms of performance, this is a world record for silicon solar cells and for hydrogen production without using rare metals. It also offers a high level of stability.

The device is able to convert solar energy into hydrogen at a rate of 14.2 percent, and has already been run for more than 100 hours straight. (Image: Infini Lab / EPFL)
Enough to power a fuel cell car over 10,000km every year

An Effective and Low-Cost Solution for Storing Solar Energy

 

The method, which surpasses previous efforts in terms of stability, performance, lifespan and cost efficiency, is published in the Journal of The Electrochemical Society (“Solar-to-Hydrogen Production at 14.2% Efficiency with Silicon Photovoltaics and Earth-Abundant Electrocatalysts”). “A 12-14 m2 system installed in Switzerland would allow the generation and storage of enough hydrogen to power a fuel cell car over 10,000 km every year”, says Christophe Ballif, who co-authored the paper.

 
High voltage cells have an edge

 
The key here is making the most of existing components, and using a ‘hybrid’ type of crystalline-silicon solar cell based on hetero-junction technology. The researchers’ sandwich structure – using layers of crystalline silicon and amorphous silicon – allows for higher voltages. And this means that just three of these cells, interconnected, can already generate an almost ideal voltage for electrolysis to occur. The electro-chemical part of the process requires a catalyst made from nickel, which is widely available.

 
“With conventional crystalline silicon cells, we would have to link up four cells to get the same voltage,” says co-author Miguel Modestino at EPFL.”So that’s the strength of this method.”

 
A stable and economically viable method 

The new system is unique when it comes to cost, performance and lifespan. “We wanted to develop a high performance system that can work under current conditions,” says Jan-Willem Schüttauf, a researcher at CSEM and co-author of the paper. “The hetero-junction cells that we use belong to the family of crystalline silicon cells, which alone account for about 90% of the solar panel market. It is a well-known and robust technology whose lifespan exceeds 25 years.

And it also happens to cover the south side of the CSEM building in Neuchâtel.”
The researchers used standard hetero-junction cells to prove the concept; by using the best cells of that type, they would expect to achieve a performance above 16%.

 
Source: Ecole Polytechnique Fédérale de Lausanne

 

Researcher Realizes Water-Splitting Solar Cell Structure Using Nanoparticles

Published on June 18, 2013 at 6:47 AM

Due to the fluctuating availability of solar energy, storage solutions are urgently needed. One option is to use the electrical energy generated inside solar cells to split water by means of electrolysis, in the process yielding hydrogen that can be used for a storable fuel. Researchers at the HZB Institute for Solar Fuels have modified so called superstrate solar cells with their highly efficient architecture in order to obtain hydrogen from water with the help of suitable catalysts. This type of cell works something like an “artificial leaf.”

This complex solar cell is coated with two different catalysts and works like an “artificial leaf”, using sunlight to split water and yield hydrogen gas.

But the solar cell rapidly corrodes when placed in the aqueous electrolyte solution. Now, Ph.D. student Diana Stellmach has found a way to prevent corrosion by embedding the catalysts in an electrically conducting polymer and then mounting them onto the solar cell’s two contact surfaces, making her the first scientist in all of Europe to have come up with this solution. As a result, the cell’s sensitive contacts are sealed to prevent corrosion with a stable yield of approx. 3.7 percent sunlight.

Hydrogen stores chemical energy and is highly versatile in terms of its applicability potential. The gas can be converted into fuels like methane as well as methanol or it can generate electricity directly inside fuel cells. Hydrogen can be produced through the electrolytic splitting of water molecules into hydrogen and oxygen by using two electrodes that are coated with suitable catalysts and between which a minimum 1.23 volt tension is generated. The production of hydrogen only becomes interesting if solar energy can be used to produce it. Because that would solve two problems at once: On sunny days, excess electricity could yield hydrogen, which would be available for fuel or to generate electricity at a later point like at night or on days that are overcast.

New approach with complex thin film technologies

At the Helmholtz Centre Berlin for Materials and Energy (HZB) Institute for Solar Fuels, researchers are working on new approaches to realizing this goal. They are using photovoltaic structures made of multiple ultrathin layers of silicon that are custom-made by the Photovoltaic Competence Centre Berlin (PVcomB), another of the HZB’s institutes. Since the cell consists of a single – albeit complex – “block,” this is known as a monolithic approach. At the Institute for Solar Fuels, the cell’s electrical contact surfaces are coated with special catalysts for splitting water. If this cell is placed in dilute sulphuric acid and irradiated with sun-like light, a tension is produced at the contacts that can be used to split water. During this process, it is the catalysts, which speed up the reactions at the contacts, that are critically important.

Protection against corrosion

The PVcomB photovoltaic cells’ main advantage is their “superstrate architecture”: Light enters through the transparent front contact, which is deposited on the carrier glass; there is no opacity due to catalysts being mounted onto the cells, because they are located on the cell’s back side and are in contact with the water/acid mixture. This mixture is aggressive, that is to say, it is corrosive, so much so that Diana Stellmach had to first replace the usual zinc oxide silver back contact with a titanium coat approximately 400 nanometers thick. In a second step, she developed a solution to simultaneously protect the cell against corrosion with the mounting of the catalyst: She mixed nanoparticles of RuO₂ with a conducting polymer (PEDOT:PSS) and applied this mixture to the cell’s back side contact to act as a catalyst for the production of oxygen. Similarly, platinum nanoparticles, the sites of hydrogen production, were applied to the front contact.

Stable H₂-Production

In all, the configuration achieved a degree of efficacy of 3.7 percent and was stable over a minimum 18 hours. “This way, Ms. Stellmach is the first ever scientist anywhere in Europe to have realized this kind of water-splitting solar cell structure,” explains Prof. Dr. Sebastian Fiechter. And just maybe anywhere in the World, as photovoltaic membranes with different architectures have proved far less stable.

Yet the fact remains that catalysts like platinum and RuO₂ are rather expensive and will ultimately have to give way to less costly types of materials. Diana Stellmach is already working on that as well; she is currently in the process of developing carbon nanorods that are coated with layers of molybdenum sulphide and which serve as catalysts for hydrogen production.

Watch the “artificial leaf” in action: http://www.helmholtz-berlin.de/aktuell/pr/mediathek/video/energieversorgung/superstratzelle_de.html

Source: http://www.helmholtz-berlin.de/

Nanotechnology Simplifies Hydrogen Production for Clean Energy

Stony Brook University, · 310 Admin · Stony Brook, NY 11794-0701

SBU-Led Research Reveals Nanotechnology Simplifies Hydrogen Production for Clean Energy
Researcher says project is first ever demonstration of the potential of using metal nanoparticles to make fuel from water
Nov 20, 2012 – 3:30:00 PM

STONY BROOK, NY, November 20, 2012– In the first-ever experiment of its kind, researchers have demonstrated that clean energy hydrogen can be produced from water splitting by using very small metal particles that are exposed to sunlight. In the article, “Outstanding activity of sub-nm Au clusters for photo-catalytic hydrogen production,” published in the journal Applied Catalysis B: Environmental,  Alexander Orlov, PhD, an Assistant Professor of Materials Science & Engineering at Stony Brook University, and his colleagues from Stony Brook and Brookhaven National Laboratory, found that the use of gold particles smaller than one nanometer resulted in greater hydrogen production than other co-catalysts tested.

“This is the first ever demonstration of the remarkable potential of very small metal nanoparticles [containing fewer than a dozen atoms] for making fuel from water,” said Professor Orlov. Using nanotechnology, Professor Orlov’s group found that when the size of metal particles are reduced to dimensions below one nanometer, there is a tremendous increase in the ability of these particles to facilitate hydrogen production from water using solar light. They observed a “greater than 35 times increase” in hydrogen evolution as compared to ordinary materials.

Experimental and theory predicted optical properties of supported sub-nanometer particles.

In order to explain these fascinating results, Professor Orlov collaborated with Brookhaven National Lab computational scientist Dr. Yan Li, who found some interesting anomalies in electronic properties of these small particles.  Professor Orlov noted that there is still a tremendous amount of work that needs be done to understand this phenomenon. “It is conceivable that we are only at the beginning of an extraordinary journey to utilize such small particles [of less than a dozen atoms in size] for clean energy production,” he said.

“In order to reduce our dependence on fossil fuels it is vital to explore various sustainable energy options,” Professor Orlov said. “One possible strategy is to develop a hydrogen-based energy economy, which can potentially offer numerous environmental and energy efficiency benefits. Hydrogen can conceivably be a promising energy source in the future as it is a very clean fuel, which produces water as a final combustion product. The current challenge is to find new materials, which can help to produce hydrogen from sustainable sources, such as water.”

Professor Orlov also serves as a faculty member of the Consortium for Inter-Disciplinary Environmental Research at Stony Brook University. Members of his research team include Peichuan Shen and Shen Zhao from the Department of Materials Science and Engineering at Stony Brook and Dr. Dong Su of the Center for Functional Nanomaterials at Brookhaven National Laboratory.

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Editors’ Note: This project was partially funded by an $80,500 exploratory grant from the National Science Foundation.