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 Ω 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 μmol 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.
Keywords: CO(2) reduction; Heterogeneous electrocatalysts; Methanol; Photocathode; Plasmonics; Sustainable liquid fuels.
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