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

The synergistic photoelectrochemical (PEC) technology is a robust process for the conversion of CO into fuels. However, designing a highly efficient UV-visible driven photoelectrocatalyst is still challenging. Herein, a plasmonic Ag NPs modified TiO/RGO photoelectrocatalyst (Ag-TiO/RGO) has been designed for the PEC CO reduction into selective production of CHOH. HR-TEM analysis revealed that Ag and TiO 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-TiO/RGO nanohybrids. Under VU-Vis light illumination, Ag-TiO/RGO photocathode possessed a current density of 23.5 mA cm and a lower electrode resistance value of 125 Ω in CO-saturated 1.0 M KOH-aqueous electrolyte solution. Catalytic studies showed that the Ag-TiO/RGO photocathode possessed a remarkable PEC CO reduction activity and selective production of CHOH with a yield of 85 μmol L cm, the quantum efficiency of 20% and Faradic efficiency of 60.5% at onset potential of -0.7 V. A plausible PEC CO reduction mechanism over Ag-TiO/RGO photocathode is schematically demonstrated. The present work gives a new avenue to develop high-performance and stable photoelectrocatalyst for PEC CO reduction towards sustainable liquid fuels production.