It is not enough to develop an ideal hydrogen evolution reaction (HER) electrocatalysts by single strategy. Here, the HER performances are significantly improved by the combined strategies of P and Se binary vacancies and heterostructure engineering, which is rarely explored and remain unclear. As a result, the overpotentials of MoP/MoSe2 -H heterostructures rich in P and Se binary vacancies are 47 and 110 mV at 10 mA cm-2 in 1 m KOH and 0.5 m H2 SO4 electrolytes, respectively. Especially, in 1 m KOH, the overpotential of MoP/MoSe2 -H is very close to commercial Pt/C at the beginning and even better than Pt/C when current density is over 70 mA cm-2 . The strong interactions between MoSe2 and MoP facilitate electrons transfer from P to Se. Thus, MoP/MoSe2 -H possesses more electrochemically active sites and faster charge transfer capability, which are all in favor of high HER activities. Additionally, Zn-H2 O battery with MoP/MoSe2 -H as cathode is fabricated for simultaneous generation of hydrogen and electricity, which displays the maximum power density of up to 28.1 mW cm-2 and stable discharging performance for 125 h. Overall, this work validates a vigorous strategy and provides guidance for the development of efficient HER electrocatalysts.
Keywords: MoP/MoSe 2; Zn-H 2O batteries; hydrogen evolution reaction; phosphorus vacancies; selenium vacancies.
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