Toward rational design of dual-metal-site single atom electrocatalysts for hydrogen and oxygen evolution reactions

Abstract

Dual-metal-site catalysts (DMSCs) have emerged as a frontier in the field of heterogeneous catalysis due to they can improve the original structure catalytic performances of water splitting, including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). However, the effective DMSCs for HER and OER is still lacking due to their limited activity and complex electronic interactions of metal sites. Here, the HER and OER activities of 12 DMSCs and 6 single-metal-site catalysts (SMSCs) are investigated by density functional theory (DFT) calculations. It is found that N4-coordinated DMSCs and SMSCs exhibit better OER performance than that with N3-coordinated structures, in which Fe/Co-N4-a-Fe-Gr and Co/Ni-N4-a-Ni have the best OER and HER performances, with the corresponding ηOER and ΔGH* are 0.32 V and −0.02 eV, respectively. In addition, strong linear relationships are found between ΔG*O and ΔG*OH, ΔG*OOH and ΔG*OH (correlation coefficient, R2 almost equal to 1). There is a significant volcanic curve and a strong linear relationship between the metal-loaded d-band center (εd) and ηOER, εd and ΔG*OH in N4-coordinated DMSCs, respectively. The dynamics simulations results indicated that most of DMSCs are dynamically stable at reaction temperature.