Transition metal single-atom anchored g-CN monolayer for constructing high-activity multifunctional electrocatalyst

Abstract Exploring highly efficient, economical and environment-friendly multifunctional electrocatalysts is an essential precondition for the development of renewable energy conversion and storage technology. Herein, a systematic computation based on the density functional theory (DFT) was conducted to examine the potentiality of the isolated transition metal (TM) atom anchored on g-CN, expressed as TM@CN (TM = Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt and Au), as multifunctional electrocatalysts toward HER, OER and ORR. Among these candidates, Rh@CN and Pd@CN are predicted to be the promising trifunctional catalysts, being capable of driving HER/OER/ORR with the ultralow overpotentials of 0.21/0.33/0.64 V and 0.14/0.58/0.48 V, respectively, which can compete with or even outperform the currently well-developed catalysts. Importantly, the d-band center of TM atom can serve as an ideal descriptor for the adsorption energy of oxygenated intermediates. Such superb catalytic activity can be ascribed to the synergistic effect of TM and g-CN, which can effectively guarantee outstanding conductivity and electron transfer, thus tuning the interaction strength of adsorbates and optimizing the catalytic performance. The tunable catalytic activity of TM@CN would open a new perspective for optimizing catalytic performances and stimulate the developments of promising multifunctional electrocatalysts for renewable energy applications.