An integrated photocatalytic/enzymatic system for the reduction of CO2 to methanol in bioglycerol-water

A hybrid enzymatic/photocatalytic approach for the conversion of CO2 into methanol is described. For the approach discussed here, the production of one mol of CH3OH from CO2 requires three enzymes and the consumption of three mol of NADH. Regeneration of the cofactor NADH from NAD(+) was achieved by using visible-light-active, heterogeneous, TiO2-based photocatalysts. The efficiency of the regeneration process is enhanced by using a Rh(III)-complex for facilitating the electron and hydride transfer from the H-donor (water or a water-glycerol solution) to NAD(+). This resulted in the production of 100 to 1000 mol of CH3OH from one mol of NADH, providing the possibility for practical application.