PbS@NiFe-LDH heterojunction: an efficient photo-assisted electrocatalyst for the OER

Abstract

Recently, photo-assisted electrocatalysis as an emerging catalytic approach that combines the technologies of photocatalysis and electrocatalysis has attracted great interest among researchers. Under this circumstance, the NiFe-LDH compounded with PbS based (PbS@NFHS) heterojunction with both photoactive and electrocatalytic properties was constructed for the first time through an ambient etching route and a subsequent low-temperature hydrothermal method. The as-prepared catalyst displayed a novel hierarchical 3D open structure based on nanosheets, which offered numerous electrochemically active sites, facilitated the swift diffusion of ions and enhanced both electrical conductivity and catalytic stability, thus significantly improving the catalytic performance. Furthermore, the charge redistribution in the p–n junction led to the formation of space-charge regions and a built-in electric field, which benefited the charge transfer and thereby enhanced the intrinsic activity. Under illumination, electrochemical tests showed that the overpotential was only 291 mV for the OER at 50 mA cm⁻² in 1 M KOH solution, which was 50 mV lower than that without illumination. Moreover, the catalyst can maintain stability for 40 hours at a current of 10 mA cm⁻² in 1 M KOH. Compared to the traditional electrocatalytic OER, this work employed a very promising photo-assisted electrocatalytic strategy, which could further broaden the wide application of NiFe-LDH.