Selective solar-driven reduction of CO₂ to methanol using a catalyzed p-GaP based photoelectrochemical cell

With rising atmospheric CO₂ levels, there has been increasing interest in artificial photosynthetic schemes for converting this greenhouse gas into valuable fuels and small organics. Photoelectrochemical schemes for activating the inert CO₂ molecule, however, operate at excessive overpotentials and thus do not convert actual light energy to chemical energy. Here we describe the selective conversion of CO₂ to methanol at a p-GaP semiconductor electrode with a homogeneous pyridinium ion catalyst, driving the reaction with light energy to yield faradaic efficiencies near 100% at potentials well below the standard potential.