Hybrid Molecular Photoanodes for Water Oxidation Based on Electropolymerized Cu Macrocyclic Complexes on BiVO4-WO3

The conversion of sunlight into chemical energy provides a sustainable alternative to fossil fuels that can significantly contribute to the mitigation of climate change. In this regard, water splitting with sunlight using semiconductors coupled with redox catalysts emerges as a potential pathway to generate green hydrogen. Here, the performance of molecular hybrid materials composed of inorganic semiconductors, WO3-BiVO4, combined with molecular water oxidation catalysts based on Cu macrocyclic complexes is described. It is found that the charge transfer from BiVO4 to the molecular catalyst occurs on a similar time scale to the direct interfacial hole transfer to water, with a concomitant 62% decrease in the recombination rate because recombination centers are passivated upon deposition of the Cu molecular catalyst on the WO3-BiVO4 junction. Overall, this results in an improvement of the photocurrent as well as long-term stability of the new hybrid materials generated.