A team of researchers has developed an innovative way to accelerate oxygen evolution reactions to increase hydrogen production efficiency in electrocatalytic water splitting systems. Oxygen evolution reactions are currently the only real-world use of electrocatalytic water splitting used for hydrogen fuel cell production.
In the research, published in Nature Energy, the team demonstrated that the spin-orbit coupling that is inherent in these materials can be exploited to boost activity and facilitate accelerated electrocatalytic water splitting.
"Our research was driven by the pressing need for clean and sustainable energy solutions," said Xia Wang, first author of the paper. "Specifically, we aimed to address the challenge of improving electrocatalytic water splitting for hydrogen production, with a focus on the OER, a critical step often hindered by sluggish kinetics. The inspiration came from the distinctive electron transport properties of topological chiral semimetals, which offered a promising pathway to address the limitations of traditional catalysts."
To accomplish their goal of harnessing the quantum properties of chiral semimetals to enhance OER efficiency the researchers synthesized Rh-based topological chiral semimetals with a variety of SOC strengths.
"These materials feature both highly ordered geometrical chirality and electronic chirality, which enable the generation of spin-polarized carriers critical for enhancing catalytic activity," explained Wang. "By benchmarking their performance against achiral reference materials, we demonstrated that the chiral crystals significantly outperform state-of-the-art catalysts, such as RuO2, achieving up to two orders of magnitude higher specific activity in alkaline electrolytes."
The results of their study demonstrate a direct link between SOC strength of the semimetals, spin polarization, and the catalytic activity of the material. These findings could guide the future of water splitting electrocatalysts design.
"The most notable achievement of our study is the experimental validation of a direct link between SOC and OER performance, establishing a robust design principle for spin-dependent catalysts," said Wang. "Among the materials we studied, RhBiS emerged as a standout performer, demonstrating remarkable OER activity, with specific activity far exceeding that of conventional catalysts."