Excellent HER and OER Catalyzing Performance of Se‐Vacancies in Defects‐Engineered PtSe2: From Simulation to Experiment

Abstract Faced with grave climate change and enormous energy demands, effective catalysts have become more and more important due to their significant effects on reducing fossil fuels consumption. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) by water splitting are feasible ways to produce clean sustainable energy. Here, atomic structures and related scanning tunneling microscope images of Se defects in PtSe 2 are systematically explored. The equilibrium fractions of vacancies under variable conditions are predicted in detail. In addition, it is found that the vacancies are highly kinetically stable, without recovering or aggregation. The Se vacancies in PtSe 2 can dramatically enhance the HER performance, comparing to Pt(111). It is also revealed that a PtSe 2 monolayer with Se vacancies is also a good OER catalyst. The excellent bipolar catalysis of Se vacancies is further confirmed by experimental measurements. A defective PtSe 2 made via direct selenization of Pt foil at 773 K using a chemical vapor deposition process is produced. It is shown that the HER and OER performance of defective PtSe 2 is much more efficient than Pt foils by a series of measurements. This work, with its compelling theoretical and experimental studies indicates PtSe 2 with Se defects is an ideal bipolar candidate for HER and OER.