Synthesis of TiO_2/RGO with plasmonic Ag nanoparticles for highly efficient photoelectrocatalytic reduction of CO_2 to methanol toward the removal of an organic pollutant from the atmosphere

摘要

The synergistic photoelectrochemical (PEC) technology is a robust process for the conversion of CO2 into fuels. However, designing a highly efficient UV-visible driven photoelectrocatalyst is still challenging. Herein, a plasmonic Ag NPs modified TiO2/RGO photoelectrocatalyst (Ag-TiO2/RGO) has been designed for the PEC CO2 reduction into selective production of CH3OH. HR-TEM analysis revealed that Ag and TiO2 NPs with average sizes of 4 and 7 nm, respectively, were densely grown on the few-micron-sized 2D RGO nanosheets. The physicochemical analysis was used to determine the optical and textural properties of the Ag-TiO2/RGO nanohybrids. Under VU-Vis light illumination, Ag-TiO2/RGO photocathode possessed a current density of 23.5 mA cm(-2) and a lower electrode resistance value of 125 Omega in CO2-saturated 1.0 M KOH-aqueous electrolyte solution. Catalytic studies showed that the Ag-TiO2/RGO photocathode possessed a remarkable PEC CO2 reduction activity and selective production of CH3OH with a yield of 85 timol L-1 cm(-2), the quantum efficiency of 20% and Faradic efficiency of 60.5% at onset potential of -0.7 V. A plausible PEC CO2 reduction mechanism over Ag-TiO2/RGO photocathode is schematically demonstrated. The present work gives a new avenue to develop high-performance and stable photoelectrocatalyst for PEC CO2 reduction towards sustainable liquid fuels production. (C) 2021 Elsevier Ltd. All rights reserved.