Piezo-phototronic effect boosted catalysis in plasmonic bimetallic ZnO heterostructure with guided fermi level alignment

Abstract

High photo-induced carriers (PCs) recombination rate, low PC mobility, and limited solar energy utilization rate are the three main roadblocks that severely limit the photocatalytic activity of semiconductors. In this work, we designed a plasmonic bimetallic ZnO nanorod array (Au/ZnO/Pt) with Au nanoparticles (NPs) located on top of ZnO nanorods and Pt NPs evenly distributed on the ZnO nanorods for improving catalysis through the piezo-phototronic effect. With the rational design of guided Fermi level alignment, the photoinduced hot electrons of Au NPs with localized surface plasmon resonance effect can transfer to Pt NPs through ZnO to promote the separation and migration of PC. More importantly, under the stimulation of ultrasound, ZnO with piezo-phototronic effect generates an interfacial piezo-potential, thereby further promoting the separation and transport of carriers in compliance with the direction of piezo-potential to promote the surface redox reaction. Under the synergy of piezo-phototronic effect and localized surface plasmon resonance effect, the Au/ZnO/Pt realized 97.5% dye degradation in 60 min, which was 1.2, 1.36, and 1.79 folds of that with Au/ZnO/Au, Pt/ZnO/Pt, and ZnO, respectively. The unique plasmonic bimetallic heterostructure with piezo-phototronic effect and guided Fermi level alignment can guide the directional migration of carriers and provides useful instruction for the design of high-efficiency catalysts.