Uses the power of the sun to mimic underwater photosynthesis to generate hydrogen.
A team of international researchers, affiliated with UNIST has recently engineered a new artificial leaf that can convert sunlight into fuel with groundbreaking efficiency.
The research results achieved by Professor Jae Sung Lee and Professor Ji-Wook Jang of Energy and Chemical Engineering at UNIST in collaboration with Professor Roel van de Krol at the Helmholtz-Zentrum Berlin, Germany was published in the December issue of the renowned scientific journal, Nature Communications.
In the study, the research presented a hetero-type dual photoelectrodes, in which two photoanodes of different bandgaps are connected in parallel for extended light harvesting. Their new artificial leaf mimics the natural process of underwater photosynthesis of aquatic plants to split water into hydrogen and oxygen, which can be harvested for fuel.
This study is expected to contribute greatly to the reduction and treatment of carbon dioxide emissions in accordance with the recent Paris Agreement on climate change. Because using hydrogen produced by artificial leaf as fuel, does not generate carbon dioxide emissions. In addition, it can be used as a cheap and stable hydrogen fuel for hydrogen fuel cell vehicles.
Just like any other plants, marine plants also generate energy from the sun through photosynthesis. However, it is difficult to receive the full sunlight deep under the sea. Therefore, they are subjected to various types of photosynthesis that selectively utilize wavelengths reaching their depths.
“We aim to achieve 10% enhanced light harvesting efficiency within three years,” says Professor Lee. “This technology will greatly contribute to the establishment of the renewable-energy-type hydrogen refueling station by supplying cheap fuel for hydrogen fuel cell vehicles.
Osaka University researchers develop efficient “green” hydrogen production system that operates at room temperature in air.
Hydrogen gas is a promising alternative energy source to overcome our reliance on carbon-based fuels, and has the benefit of producing only water when it is reacted with oxygen. However, hydrogen is highly reactive and flammable, so it requires careful handling and storage. Typical hydrogen storage materials are limited by factors like water sensitivity, risk of explosion, difficulty of control of hydrogen-generation. Hydrogen gas can be produced efficiently from organosilanes, some of which are suitably air-stable, non-toxic, and cheap. Catalysts that can efficiently produce hydrogen from organosilanes are therefore desired with the ultimate goal of realizing safe, inexpensive hydrogen production in high yield. Ideally, the catalyst should also operate at room temperature under aerobic conditions without the need for additional energy input.
A research team led by Kiyotomi Kaneda and Takato Mitsudome at Osaka University have now developed a catalyst that realizes efficient environmentally friendly hydrogen production from organosilanes. The catalyst is composed of gold nanoparticles with a diameter of around 2 nm supported on hydroxyapatite. The catalyst was synthesized from chloroauric acid using glutathione as a capping agent to prevent nanoparticle aggregation, resulting the formation of small size of gold nanoparticles. Glutathione-capped gold nanoparticles were then adsorbed on hydroxyapatite and glutathione was removed by subsequent calcination.
The team then added the nanoparticle catalyst to solutions of different organosilanes to measure its ability to induce hydrogen production. The nanoparticle catalyst displayed the highest turnover frequency and number attained to date for hydrogen production catalysts from organosilanes. For example, the nanoparticle catalyst converted 99% of dimethylphenylsilane to the corresponding silanol in just 9 min at room temperature, releasing an equimolar amount of hydrogen gas at the same time. Importantly, the catalyst was recyclable without loss of activity. On/off switching of hydrogen production was achieved using the nanoparticle catalyst because it could be easily separated from its organosilane substrate by filtration. The activity of the catalyst increased as the nanoparticle size decreased.
A prototype portable hydrogen fuel cell containing the nanoparticle catalyst and an organosilane substrate was fabricated. The fuel cell generated power in air at room temperature and could be switched on and off as desired. Images of the catalyst after use in the fuel cell resembled those of the unused catalyst, indicating that the hydroxyapatite-supported nanoparticle catalyst readily resisted aggregation.
Generation of hydrogen from inexpensive organosilane substrates under ambient conditions without additional energy input represents an exciting advance towards the goal of using hydrogen as a green energy source.
Simpler process and higher efficiency creates great expectations for consumer market
Waseda University researchers have developed a new method for producing hydrogen, which is fast, irreversible, and takes place at much lower temperature using less energy. This innovation is expected to contribute to the spread of fuel cell systems for automobiles and homes.
Hydrogen has normally been extracted from methane and steam using a nickel catalyst at temperatures of over 700°C. However, the high temperature creates major challenges for widespread use.
The group led by Professor Yasushi Sekine, Waseda University Faculty of Science and Engineering, developed a method which allows hydrogen extraction at temperatures as low as 150~200°C. This shift greatly reduces energy input needed to produce hydrogen fuel, extends catalyst life, reduces the cost of construction materials, and reduces complexity of heat-management (cooling) systems.
Although the research group had already seen that a fast reaction would be possible even in the range of 150~200°C by applying a weak electric fields (surface protonics), the mechanism had not been fully understood.
In this research, the group is the first to explain the mechanism by observing the catalyst during reaction. Protons move quickly through water adsorbed on the catalyst’s surface, and protons’ surface “hopping” allows reaction to proceed at low temperatures. Furthermore, the collision of the protons and the adsorbents prevents reversal of the reaction.
As momentum grows for the commercialization of hydrogen, this research is not only applicable to hydrogen production, but also to many consumer products since the same mechanism makes it possible to lower the temperature for various reactions involving hydrogen or water. The process is already being applied to research for improving energy efficiency in automobiles by creating reactions between exhaust gases and fuel at low temperature.
A team of UK researchers, including experts from Cardiff University’s Cardiff Catalysis Institute, have shown that significant amounts of hydrogen can be unlocked from fescue grass with the help of sunlight and a cheap catalyst.
It is the first time that this method has been demonstrated and could potentially lead to a sustainable way of producing hydrogen, which has enormous potential in the renewable energy industry due to its high energy content and the fact that it does not release toxic or greenhouse gases when it is burnt.
Co-author of the study Professor Michael Bowker, from the Cardiff Catalysis Institute, said: “This really is a green source of energy.
“Hydrogen is seen as an important future energy carrier as the world moves from fossil fuels to renewable feedstocks, and our research has shown that even garden grass could be a good way of getting hold of it.”
KTH researchers have opened a route to large-scale hydrogen production by discovering a better way to split water without relying on precious metals.
If a cheap, stable and efficient way could be found to produce hydrogen from water, a hydrogen-fuel economy could finally become a reality.
Scientists at KTH Royal Institute of Technology in Stockholm now report that they have unlocked one major barrier to exploiting this renewable energy source.
Because the best-performing catalysts for electrochemical oxidation, or “water splitting”, are expensive precious metals, the research team led by KTH Professor Licheng Sun is one of many worldwide searching for cheaper alternatives. Sun had earlier developed molecular catalysts for water oxidation () with an efficiency approaching that of natural photosynthesis.
Last week his teamthat it has discovered that a new material composed of common earth-abundant elements could be used as a catalyst for water splitting, which could help change the economics of large scale hydrogen fuel production.
The team headed by Dr Jens Noth and Prof Dr Thomas Happe at the Ruhr-Universität Bochum report the results in the journal “Angewandte Chemie”. The researchers intend to lay the foundation for artificial, hydrogen-producing enzymes that will one day be manufactured on an industrial level. Hydrogenases are very efficient producers of the potential energy carrier and can do without the expensive precious metal platinum which is currently required for hydrogen synthesis.
Scientists synthesize what could be a low-cost, earth-abundant material that splits water to make hydrogen fuel.
Storing energy from sunlight or wind inside the bonds of a hydrogen (H2) molecule would let intermittent renewable energy power fuel cells, providing electricity on demand. The scalable production of H2, created by splitting apart water (H2O), depends on how well the catalysts drive the reaction. Thus far, platinum catalysts are the best, but the metal’s scarcity and cost is problematic. A layered material shows great promise as a low-cost alternative. Scientists showed that a microwave synthesis technique helps create the new material, a nanostructured molybdenum disulfide, and gives the catalyst an improved ability to produce hydrogen.
Microwave-prepared molybdenum disulfide material has the potential to be an affordable alternative to the expensive platinum catalysts that are currently used. The performance exceeds that of MoS2 materials made via other synthetic methods.
Rice University catalyst holds promise for clean, inexpensive hydrogen production
Graphene doped with nitrogen and augmented with cobalt atoms has proven to be an effective, durable catalyst for the production of hydrogen from water, according to scientists at Rice University.
The Rice lab of chemist James Tour and colleagues at the Chinese Academy of Sciences, the University of Texas at San Antonio and the University of Houston have reported the development of a robust, solid-state catalyst that shows promise to replace expensive platinum for hydrogen generation.