Cobalt-doped CdS quantum dots enhanced photoelectroreduction of CO2 to formic acid with high selectivity

Excessive carbon dioxide (CO2) emission has caused problems associated with environmental pollution and climate deterioration. As a consequence, the selective conversion of CO2 into liquid fuels by artificial photosynthesis has gained increasing attention. However, the rational design of photocathode to achieve selective CO2 photoelectroreduction is challenging. Here, we sensitized cuprous oxide (p-nCu2O) loaded on hydroxyl iron oxide (FeOOH) with cobalt-doped cadmium sulfide (Co:CdS) quantum dots to prepare a novel photocathode FeOOH/p-nCu2O/Co:CdS by sequential electrodeposition and chemical bath deposition. The composite photocathode exhibited a larger photovoltage, which is 1.9 times higher than the pristine counterpart, and was efficient for CO2 reduction to produce formic acid with high selectivity of up to 82.9