Nanomaterial could speed up hydrogen fuel production
Image credit: Dreamstime
Researchers from Lawrence Berkeley National Laboratory in the US have created a relatively inexpensive and stable material which speeds up the extraction of hydrogen from alcohols, potentially accelerating the production of hydrogen fuel.
There is increasing interest in using hydrogen – a sustainable and clean source of energy – to replace polluting fuels in aviation, power generation and other industries. However, traditional means of storage and transport are expensive and susceptible to contamination. Low-cost and efficient hydrogen-delivery systems would benefit many applications, rendering the hydrogen economy more viable.
Now, researchers have designed and synthesised a catalyst for speeding up one of the limiting steps in extracting hydrogen atoms from a liquid carrier. The material is made from tiny clusters of nickel metal anchored on a 2D substrate. While existing catalysts of high performance and stability are made from precious metals, this catalyst does not require such expensive raw materials.
“We present here not merely a catalyst with higher activity than other nickel catalysts that we tested, for an important renewable energy fuel, but also a broader strategy toward using unaffordable metals in a broad range of reactions,” said Jeff Urban, who led the work.
Urban and his colleagues modified an existing strategy which focuses on tiny, uniform clusters of nickel metal. These tiny clusters maximise the exposure of reaction surface in a given mass of material. However, they tend to clump together, restricting their reactivity.
The researchers tried combatting this clumping by depositing 1.5nm nickel clusters on a 2D substrate made of boron and nitrogen, which was designed to host a grid of atomic-scale “dimples”. This allowed the nickel clusters to disperse and anchor evenly. This design not only prevented clumping, but its thermal and chemical properties also greatly improved the catalyst’s overall performance by directly interacting with the nickel clusters.
“The role of the underlying surface during the cluster formation and deposition stage has been found to be critical, and may provide clues to understanding their role in other processes,” Urban said.
The researchers’ observations led them to propose that the material forms while metal clusters occupy pristine regions of the sheets and interact with nearby edges, preserving the tiny size of the clusters. These clusters facilitated the action in the processes through which hydrogen is separated from its carrier, boosting the selectivity, productivity, and stability of the catalyst.
The size of the catalyst was key to this improvement in performance; exposed metal atoms on the clusters are more readily attracted to the liquid carrier than larger metal particles. These exposed atoms also eased the chemical reaction that strips hydrogen from the carrier, while preventing the formation of contaminants that may clog the surface of the cluster.
Introducing these catalytic and anti-contamination properties ultimately helped the researchers keep the cluster size so small.
“Contamination can render possible non-precious metal catalysts unviable,” said Urban. “Our platform here opens a new door to engineering those systems.”
The research was part of the US Department of Energy’s Hydrogen Materials Advanced Research Consortium, which aims to address the scientific gaps blocking the advancement of solid hydrogen storage materials.
Meanwhile in the UK, the government is planning to work with industry to generate 5GW of low-carbon hydrogen production capacity by 2030, (targeting industry, transport, power generation and domestic heating, and to develop the first town heated entirely by hydrogen.
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