Activity Origins of Graphdiyne Based Bifunctional Atom Catalysts for Hydrogen Evolution and Water Oxidation

Graphdiyne(GDY) based atom catalysts(ACs) show extraordinary electrocatalytic activities towards hydrogen evolution reaction(HER) and water oxidation reaction(OER), which have attracted wide attention of scientists. However, a precise understanding on the activities trends and origins of ACs is still under exploration. We investigate the electrocatalytic performance of a series of ACs in this work. Density functional theory(DFT) calculations reveal that the half reactions of OER and HER are site-dependent on ACs, which are preferentially proceeded on the metal site and the nearby bonded carbon site, respectively. Besides, the d-band center of metal atoms is the most important descriptor, which can perfectly correlate the high activities of ACs towards the two half reactions. Especially for HER, the deeper d-band position of metal atoms corresponds to much stronger d-px(py) orbital coupling in ACs, which activate more obvious charge transfer between the metal site and the nearby bonded carbon site, resulting in the HER activity enhancement of ACs. These results are of great significance in guiding the precise synthesis of highly efficient bifunctional metal atom catalysts supported by GDY in future.