Photochemical Carbon Dioxide Reduction on Mg-Doped Ga(In)N Nanowire Arrays under Visible Light Irradiation

The photochemical reduction of carbon dioxide (CO 2 ) into energy-rich products can potentially address some of the critical challenges we face today, including energy resource shortages and greenhouse gas emissions. Our ab initio calculations show that CO 2 molecules can be spontaneously activated on the clean nonpolar surfaces of wurtzite metal nitrides, for example, Ga(In)N. We have further demonstrated the photoreduction of CO 2 into methanol (CH 3 OH) with sunlight as the only energy input. A conversion rate of CO 2 into CH 3 OH (∼0.5 mmol g cat –1 h –1 ) is achieved under visible light illumination (>400 nm). Moreover, we have discovered that the photocatalytic activity for CO 2 reduction can be drastically enhanced by incorporating a small amount of Mg dopant. The definitive role of Mg dopant in Ga(In)N, at both the atomic and device levels, has been identified. This study reveals the potential of III-nitride semiconductor nanostructures in solar-powered reduction of CO 2 into hydrocarbon fuels.