Au modified TiO2 nanowires prepared by photodeposition for selective and efficient electrochemical reduction of CO2

Electrocatalytic CO2 reduction (CO2ER) to produce formic acid (HCOOH) would be an attractive means for carbon neutralization. In order to realize efficient CO2ER and economical conversion of CO2, the applying of metal active sites on surface of semiconductor has emerged as a promising strategy. Herein, we report the preparation of alkaline modified TiO2 nanowires (NWs) as the substrate for Au photodeposition. The as-fabricated Au/TiO2 NWs exhibits high activity and selectivity towards HCOOH production compared with traditional catalysts. The key factors including deposition time, solution, and etc. And their effects on CO2ER performance have been systematically investigated. At −0.8 V vs RHE, the Faraday efficiency of the HCOOH can reach to 86.49 %, while the current density is 15.94 mA cm−2. In addition, Au/TiO2 NWs also exhibited good stability after 18 h electrocatalytic CO2RR under the voltage of −0.8 V vs RHE. Electrochemical tests indicated that Au/TiO2 NWs process favorable intrinsic electrochemical properties, high ESCA and accelerating charge transfer process make Au/TiO2 NWs obtain abundant active sites and kinetically favorable. This work provides a convenient fabrication strategy of Au/TiO2 based catalyst, which can guide the design and modification of gold for CO2ER into formic acid.