On June 7, 2022, the research work entitled "Controlling the Valence-Electron Arrangement of Nickel Active Centers for Efficient Hydrogen Oxidation Electrocatalysis" was published online in Angewandte Chemie International Edition (DOI: 10.1002/anie.202206588). This work was conducted by Prof. Wang Deli and Prof. Zhao Xu from the School of Chemistry and Chemical Engineering at Huazhong University of Science and Technology.

To achieve carbon neutrality goals, alkaline membrane fuel cells (AMFCs) have achieved much attention to be one of the representative hydrogen-conversion technologies. Nevertheless, there is still a bottleneck in developing high-performance and low-cost AMFCs, mainly due to the low activity of nickel-based catalysts for the anodic hydrogen oxidation reaction (HOR). Accordingly, the replacement of precious metal catalysts by nickel-based catalysts at the anode in AMFCs cannot be achieved, which seriously restricts the cost and efficiency of alkaline fuel cells.

To this end, Prof. Wang Deli and Prof. Zhao Xu proposed a unique strategy of controlling the valence-electron arrangement of nickel-based catalysts for high-performance HOR. Benefiting from the fabricated Ni vacancies, the electrons delocalization or missing were well-managed in the ultrathin Ni₃N nanosheets, leading to the well-regulated adsorption behaviors of key intermediates and thus significantly reduced energy barrier of alkaline HOR. Experimental results demonstrated that these Ni-vacancy-enriched Ni₃N nanosheets showed comparable activity relative to commercial Pt catalysts with suitable loading, as well as the good stability even after 2000 potential cycles. In addition, these catalysts also exhibited remarkably enhanced ability against CO poisoning for practical utilization. This work shines new lights on developing highly-efficient HOR catalysts through tuning the valence-electron arrangement.

Figure 1. The effect of introduced nickel vacancies on regulating the valence-electron arrangement of catalysts and corresponding alkaline HOR process.

This work was conducted at Huazhong University of Science and Technology by Prof. Zhao Xu as the first author and Prof. Wang Deli as the corresponding author. Meanwhile, this work was also co-authored by the researchers of DFT calculations from the University of Science and Technology of China and the researcher of XAS analysis from the Institute of High Energy Physics of the Chinese Academy of Sciences. This work was funded by the National Natural Science Foundation of China and the Fundamental Research Funds of Huazhong University of Science and Technology.

Source: School of Chemistry and Chemical Engineering

Edited by: Luo Xin, Jiang Jing