Because of its potential value in efficient and scalable hydrogen production, water splitting via the electrochemical hydrogen evolution reaction (HER) has attracted considerable attention from industrial and scientific communities. Even though they are the heart of hydrogen evolution catalysis, catalysts with satisfactory performance are still rare, despite the tremendous effort that has been devoted to improving HER catalysts. Among various approaches, sulfur (S) vacancies and strain have been introduced to activate and optimize the basal plane of monolayer 2H–MoS₂, leading to the highest intrinsic HER activity among molybdenum–sulfide-based catalysts. A high concentration of strained metallic 1T WS₂sites, obtained by chemical exfoliation, led to WS₂nanosheets with enhanced catalytic activity. Ultrathin Pt nanowires on singlelayered Ni(OH)₂nanosheets with a unique hybrid nanostructure were also achieved, and exhibited unprecedented catalytic activity and stability toward HER. Nonetheless, in spite of these achievements, strategic exploration to improve the HER performance of catalysts is still a great challenge.

OnSeptember 6, 2019, the study entitled " Balancing hydrogen adsorption/desorption by orbital modulation for efficient hydrogen evolution catalysis" was published online in Nature Communications (https://www.nature.com/articles/s41467-019-12012-z).The research was completed by Prof. Yunfei Bugroup of Nanjing University of Information Engineering in cooperation with Ulsan National Institute of Science and Technology of South Korea, Chongqing University and University of Science and Technology of China.

In this study, we report the rational design of an efficient catalyst for hydrogen evolution, by balancing hydrogen adsorption/desorption via orbital modulation. Theoretical calculations suggested that the d orbitals of Ir sites can be manipulated through strong interactions with the p orbitals of C/N atoms. They suggested that orbital modulation would further balance the hydrogen adsorption/desorption behaviors of the surficial Ir sites, enabling efficient hydrogen evolution. Inspired by the theoretical results, IrHNC was prepared by anchoring a low content of IrNP on nitrogenated carbon matrixes. As expected, the IrHNC exhibited significantly enhanced reaction kinetics, mass activity and intrinsic activity for the hydrogen evolution. This work not only highlights the rational design of a catalyst for efficient hydrogen evolution, but also introduces an opportunity to achieve enhanced catalytic performance for diverse reactions via orbital modulation.

Professor Yunfei Bu from the School of Environmental Science and Engineering at Nanjing University of Information Science & Technology, Professor Zhengping Fu and Professor Yalin Lu from University of Science and Technology of China and Professor Jong-Beom Baek from Ulsan National Institute of Science and Technology of South Korea were the co-corresponding authors. Dr. Feng Li from Ulsan National Institute of Science and Technology of South Korea was the first author of the paper.