Nanostructure With Piezo-phototronics Effect And Application In Photocatalysis

With the rapid development of economy,energy and environmental problems have become increasingly prominent.The accumulation of organic and inorganic toxic compounds caused by industrialization leads to deterioration of water,air and soil quality.These toxic compounds are dangerous that affect ecosystems and,in turn,human health.Nowadays,clean water,air and soil are important for improving human living conditions.Among various environmental remediation methods,the utilization of photocatalytic semiconductor materials and renewable solar energy to degrade pollutants is considered as a most promising green technology.During this process,low carrier mobility,high photogenerated electron-hole(PEH)recombination rate,and low solar energy utilization severely limit the photocatalytic activity of semiconductors.Here,we combine the piezo-phototronics(PPs)effect and the localized surface plasmon resonance(LSPR)effect to improve the photocatalytic activity of semiconductors.We designed an Au/Zn O/Pt nanorod array co-loaded with Au and Pt nanoparticles(NPs),where Au is mainly located on top of Zn O nanorods in the form of larger nanoparticles,and Pt is uniformly distributed on Zn O in the form of smaller nanoparticles.When Au/Zn O/Pt is excited by light,hot electrons generate from Au NPs with LSPR effect,which cross the potential barrier and reach the conduction band of Zn O.At the same time,Zn O photogenerated electrons transition from the valence band to the conduction band and migrate to the smaller Pt NPs.Pt NPs loaded on Zn O surface act as electron acceptors,trapping electrons and promoting the separation and migration of photogenerated electron-hole pairs.Since the work function of Pt is larger than that of Au,that is,the Fermi level of Pt is lower than that of Au,electron will transfer from Au to Pt via Zn O.In addition,piezo-potential of Zn O is triggered under the stimulation of ultrasound.It promotes the separation of photo-generated holes-electrons and their transport along the direction of the piezo-potential,which further promotes the oxidation-reduction reaction.Under the synergy of PPs effect and LSPR effect,the Au/Zn O/Pt realized 97.5% dye degradation in 60 min,which was 1.2,1.36,and 1.79 folds of that with Au/Zn O/Au,Pt/Zn O/Pt,and Zn O,respectively.The unique plasmonic bimetallic heterostructure with PPs effect and guided Fermi level alignment can guide the directional migration of carriers and provides useful instruction for the design of high-efficiency catalysts.