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

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) kTNT 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.