Reduction of CO2 and its direct entry into organic chemistry is achieved efficiently and in a highly visible way using a metal oxide electrode in which two enzyme catalysts, one for electrochemically regenerating NADPH, the other for assimilating CO2 and converting pyruvate (C3) to malate (C4) are entrapped within its nanopores. The resulting reversible electrocatalysis is exploited to construct a solar CO2 reduction/water splitting device producing O2 and C4 with high faradaic efficiency.
