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 Cu 2 ZnSnS 4 @TiO 2 nanotubes (Cu 2 ZnSnS 4 /TiO 2 NTs) composite electrode by pulse electrodeposition and high-temperature vulcanization, which possesses high catalytic conversion efficiency for CO 2 reduction and stable performance. In addition, the influence of pulse parameters on the morphology and photoelectrochemical properties of Cu 2 ZnSnS 4 /TiO 2 NTs composite electrode were studied in detail. The band gap of Cu 2 ZnSnS 4 /TiO 2 NTs is 1.39 eV, which is significantly reduced compared with TiO 2 NTs (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 CO 2. No new phase was generated and the photocurrent density remained 33.2% of the original after the catalytic process, which indicated the Cu 2 ZnSnS 4 /TiO 2 NTs possess stable catalytic performance. [Display omitted] • A new method was developed to prepare self-assembled composite electrode for catalytic reduction of CO 2. • Cu 2 ZnSnS4/TiO 2 NTs electrode exhibited good photoelectrocatalytic ability and high selectivity of ethanol. • The p-n junction Cu 2 ZnSnS 4 /TiO 2 NTs was obtained by optimizing pulse parameters. • The high temperature sulfidation enabled the Cu 2 ZnSnS 4 /TiO 2 NTs electrode stable in performance. [ABSTRACT FROM AUTHOR]