Polyoxometalate derived p-n heterojunction for optimized reaction interface and improved HER

MoS2is a typical electrocatalyst for hydrogen evolution reaction(HER),but the HER activity is spoilt by intensive adsorption towards H*,which requires further improvement.For n-type MoS2,the construction of p-n heterojunction with p-type MoO3can reverse this situation,because inner electronic field in p-n heterojunction can facilitate H*desorption.Based on this hypothesis,p-n heterojunction is built between MoS2and MoO3with polyoxometalate compound as precursor.The obtained MoO3/MoS2exhibits excellent HER activity,which only requires 68 mV to obtain 10 mA/cm2.With MoO3/MoS2as cathode material and Zn slice as anode,Zn-H+battery is assembled.Its open circuit voltage achieves 1.11 V with short circuit current 151.4 mA/cm2.The peak power density of this Zn-H+battery reaches 47.6 mW/cm2.When discharge at 10 mA/cm2,the specific capacity and energy density reach 728 mAh/g and 759 Wh/kg.In this process,H2production rate of Zn-H+battery achieves 364μmol/h with Faradic efficiency 97.8%.It realizes H2production and electricity generation simultaneously.