Highlights

Hybrid Photoanodes for solar fuels: when molecular catalysis makes the difference

18.05.2026 | Catalysis, Energy

Turning sunlight into fuel is one of the most compelling challenges in modern energy research. Photoelectrochemical (PEC) cells aim to do that, converting solar energy into hydrogen – a clean fuel with exceptional energy density – by splitting water. Among the most promising materials for this task are metal oxide semiconductors such as BiVO₄ and WO₃, valued for their stability and affordability. However, their performance is often limited by inefficient charge transport and rapid recombination of photogenerated carriers. 

Federico Boscherini, Alberto Piccioni, Luca Pasquini, Raffaello Mazzaro (University of Bologna) and colleagues tackles this problem by integrating a molecular copper-based water oxidation catalyst (WOC) into a BiVO₄–WO₃ heterojunction. The catalyst, based on a robust tetra-amidomacrocyclic ligand framework, is electropolymerized onto the semiconductor surface, forming a hybrid material. As demonstrated by state-of-the art spectroscopic analyses, partly performed at the LISA X-ray absorption spectroscopy beamline at CNR@ESRF (CERIC Associated Facility), this molecular system retains its integrity under operating conditions that mimic real-life operations. 

The result is a marked improvement in device performance: charge recombination is reduced by 62%, while the catalyst actively mediates hole transfer to water, enhancing both efficiency and stability during prolonged operation. Rather than acting as a passive coating, the copper complex plays a dynamic role in facilitating the oxygen evolution reaction. 

ORIGINAL ARTICLE

Hybrid Molecular Photoanodes for Water Oxidation Based on Electropolymerized Cu Macrocyclic Complexes on BiVO4-WO3
Bellido C.G., Mazzanti M., Ranu K., Piccioni A., Mazzaro R., Boscherini F., Salomón F.F., Grau S., Sala X., Pasquini L., Llobet A., Caramori S., Advanced Energy Materials, 2025