Efficient, Light-Driven Reduction of CO₂ to CO by a Carbon Monoxide Dehydrogenase-CdSe/CdS Nanorod Photosystem

The solar conversion of CO₂ to low carbon fuels has been heralded as a potential solution to combat the rise in greenhouse gas emissions. Here we report the first light-driven activation of [NiFe] CODH II from Carboxydothermus hydrogenoformans for the reduction of CO₂ to CO. To accomplish this, a hybrid photosystem composed of CODH II and CdSe/CdS dot-in-rod nanocrystals was developed. By incorporating a low-potential redox mediator to assist electron transfer, quantum yields up to 19% and turnover frequencies of 9 s^-1 were achieved. These results represent a new standard in efficient CO₂ reduction by an enzyme-based photocatalytic systems. Furthermore, successful photoactivation of CODH II allows for future exploration into the enzyme's not fully understood mechanism.