Preparation of Cu2ZnSnS4@TiO2 nanotubes by pulsed electrodeposition for efficiently photoelectrocatalytic reduction of CO2 to ethanol

In this work, we reported a method of preparing Cu2ZnSnS4@TiO2 nanotubes (Cu2ZnSnS4/TiO2NTs) composite electrode by pulse electrodeposition and high-temperature vulcanization, which possesses high catalytic conversion efficiency for CO2 reduction and stable performance. In addition, the influence of pulse parameters on the morphology and photoelectrochemical properties of Cu2ZnSnS4/TiO2NTs composite electrode were studied in detail. The band gap of Cu2ZnSnS4/TiO2NTs is 1.39 eV, which is significantly reduced compared with TiO2NTs (3.27 eV). There are differences in the morphology, catalytic efficiency and product selectivity of the catalytic interface constructed by different pulse electrodeposition parameters. The photoresponse current of the composite electrode prepared by optimizing the parameters reaches −7 μA cm−2, and the ethanol yield is 7.0 μmol cm−2 after 5 h of photoelectrocatalytic reduction of CO2. No new phase was generated and the photocurrent density remained 33.2% of the original after the catalytic process, which indicated the Cu2ZnSnS4/TiO2NTs possess stable catalytic performance.