Precisely modifying Co2P/black TiO2 S-scheme heterojunction by in situ formed P and C dopants for enhanced photocatalytic H2 production

Abstract

The construction of S-scheme heterojunction catalysts is promising for efficient photocatalytic hydrogen production, but the conscious modulation of S-scheme charge transfer has remained largely underdeveloped. Herein, P and C modified Co2P/black TiO2 S-scheme heterojunction photocatalyst (Co2P/PC-b-TiO2) is prepared by pyrolyzing a mixture of cobalt phosphonate and TiO2 under H2 atmosphere. The in situ formed P and C dopants can not only enhance the ratio of surface active O species to bulk O defects but also inhibit anatase-to-rutile phase transformation, thereby ensuring the high intrinsic activity. More importantly, the S-scheme heterojunction between PC-b-TiO2 and Co2P is modified by the incorporation of P and C, wherein the intimately coupled heterointerface and strong internal electric field can accelerate charge separation and migration and optimize the available redox potential. Accordingly, Co2P/PC-b-TiO2 displays dramatically ascendant photocatalytic hydrogen evolution performance and outstanding stability. This study provides guidance for elaborately modifying S-scheme heterojunctions through heteroatom doping and heralds a new paradigm for engineering advanced heterojunction catalysts.