Photoelectrochemical Reduction of Carbon Dioxide on Quantum-Dot-Modified Electrodes by Electric Field Directed Layer-by-Layer Assembly Methodology.

The photoelectrocatalytic reduction of CO2 on ITO-modified electrodes, with electrostatic assemblies (polycations/quantum dots) (polycations=poly diallyldimethylammonium, PDDA, and poly(2-trimethylammonium)ethyl methacrylate, PMAEMA)), is described in the present work. Nanoparticles of CdTe (5.6 nm) were incorporated through an electric field directed layer-by-layer assembly method on ITO electrodes. Modified surfaces were active toward the reduction of CO2 at -400 mV vs Ag/AgCl; the activity of ITO-(PMAEMA/QDs)6 electrodes was enhanced by 300 mV under irradiation conditions. The photoelectrocatalytic effect was associated with the structure of the polycation and its influence in the assembly. Reaction products at -450 mV were H2, CO, CH3OH, and HCOH.