Piezoelectric polarization field tuning Schottky barrier of Ni/Mn0.2Cd0.8S composite for hot electrons transfer to enhance photocatalytic hydrogen evolution

Abstract

Coupling piezoelectric effect with local surface plasmon resonance (LSPR) for visible-light-driven photocatalytic hydrogen evolution is of great significance to realize the high-efficiency solar energy conversion. In this work, Ni/Mn0.2Cd0.8S plasmon piezo-photocatalysts were constructed by combining plasma metal Ni with structural distortion-enhanced Mn0.2Cd0.8S for piezo-photocatalytic hydrogen evolution. The influence of integrating plasma Ni with piezoelectric Mn0.2Cd0.8S on the photocatalytic performance was investigated together with the wavelength dependent experiments. Under simultaneous illumination and ultrasound, the optimized 1.5 wt%-Ni/Mn0.2Cd0.8S displayed ultrahigh piezo-photocatalytic hydrogen evolution rate of 72.38 mmol g−1 h−1, which was approximately 11.8 and 25.0-fold that of Mn0.2Cd0.8S and CdS, respectively. The significantly enhanced performance was assigned to the coupling of piezoelectric and LSPR effect, through which the internal piezoelectric polarization field generated by Mn0.2Cd0.8S could change the local contact characteristics of Mn0.2Cd0.8S and Ni interface, decreasing the degree of upward bending of the band and reducing the Schottky barrier height, thus promoting the interfacial transfer of plasmon hot electrons for photocatalytic hydrogen evolution. This work provides a reliable reference for developing high-performance plasmonic piezo-photocatalysts materials based on piezoelectric and LSPR effect.