Optimizing CO2 reduction conditions to increase carbon atom conversion using a Pt-RGO||Pt-TNT photoelectrochemical cell

Abstract This study aimed to determine the optimum conditions required to increase the carbon atom conversion rate in a Pt-RGO||Pt-TNT photoelectrochemical cell. The effects of Pt-RGO reduction time on CO 2 conversion, voltage applied through the cell, catholyte pH, and pore size of nickel foam as a catalyst support were investigated. The conversion rate of C atoms initially increased and then decreased with increasing Pt-RGO reduction time, increasing electrolyte pH, and decreasing nickel foam pore size. Although carbon atom conversion showed sustainable growth as the applied voltage increased, the current efficiency of CO 2 reduction products decreased because of enhanced proton interference when the voltage applied through the cell exceeds 2 V. A maximum carbon atom conversion rate of 1500 nmol/(cm 2  h) was obtained by Pt-RGO reduction for 24 h when a 2 V voltage was applied through the cell, the catholyte pH was 8.8, and nickel foam with an average pore size of 160 μm was used as a support. Under optimum conditions, the liquid product selectivity of CO 2 reduction reached 99%. The results of the study indicate that RGO-based catalysts have potential use as blueprints for CO 2 reduction.