A Cu foam cathode used as a Pt–RGO catalyst matrix to improve CO2 reduction in a photoelectrocatalytic cell with a TiO2 photoanode

Abstract

Cu foam combined with Pt-modified reduced graphene oxide (Pt–RGO) was investigated as an efficient cathode for CO₂ reduction in a photoelectrocatalytic (PEC) cell with a TiO₂ nanotube (TNT) photoanode. The synergistic catalytic mechanisms between photocatalysis and electrocatalysis in such a photoanode driven 2-electrode PEC cell were experimentally verified and theoretically analyzed. The dual functional Cu foam, as a cathode electrode and a Pt-RGO catalyst matrix, markedly increased the carbon atom conversion rate because of its well-defined porosity, large specific surface area, and in particular its affinity for CO₂ reduction to hydrocarbons. Combination of the Cu foam matrix and Pt–RGO catalysts resulted in synergistic CO₂ reduction in the (Pt–RGO/Cu foam)‖TNT PEC cell. The carbon atom conversion rate markedly increased to 4340 nmol (h⁻¹ cm⁻²) by optimizing CO₂ reduction conditions in the PEC cell, including voltage applied through the cell, Pt loading amount on RGO, and Pt–RGO loading amount on Cu foam.