Rational design of ZnO–CuO–Au S-scheme heterojunctions for photocatalytic hydrogen production under visible light

Abstract

An integration of S-scheme heterojunction catalyst with surface plasmon resonance effect is the prime focus of current research activites in the field of visible light driven photocatalytic hydrogen (H2) evolution. Herein, a sol-gel route is used to design a heterojunction of ZnO–CuO–Au. The effect of process parameters, including irradiation time, catalyst dose, and sacrificial reagents on the hydrogen evolution is studied. The S-scheme ZnO–CuO–Au heterojunction catalyst demonstrated high surface area, better optical absorption response in the visible part of light spectrum, and improved separation and transportion of charge carriers as verified by DRS, PL, and photoelectrochemical studies. The maximum H2 evolution rateof ZnO–CuO–Au reaches 4655 μmolh−1g−1, which is 5 and 3.2 times higher than ZnO–CuO and Au–ZnO catalysts, respectively. A possible reason of this increase in H2 evolution rate is inhibited recombination of charge carriers because of the S-scheme design to increase electrons with strong reduction potential and prolong lifetime, Au serves as an SPR source and conductive channel to swift the transfer of electrons and high density of active sites. This work offers innovative insight into designing plasmonic metals-modified S-scheme systems for solar fuel production.