Polyoxometalate-based hybrid materials with electronic interaction boosting photocatalytic H2 evolution coupled with alcohol oxidation

Efficient separation of the mixed H2 and O2 products is a crucial step in the photocatalytic overall water splitting process, often hindered by the slow kinetics of the O2-producing half-reaction. One effective approach is to employ organic substrates that can capture the holes, thereby enhancing the overall reaction rate and yielding valuable alcohol oxidation products in parallel. Enhance electronic structure advantages through electrostatic interactions and intermolecular hydrogen bonding, thereby facilitating accelerated electron transfer and boosting the intrinsic photocatalytic activity. This is the first study that demonstrates the successful implementation of Ru oxo cluster-based hybrid materials with electronic interaction and intermolecular hydrogen bonding, NaH[Ru(bpy)3][Ru8(CO3)4(CO)16Cl4]·EtOH·5H2O. The triethanolamine sacrificial reaction system has a remarkable 15-fold increase in H2 evolution, alongside concurrent H2 production coupled with 1-(4-chlorophenyl)ethanol oxidation reactions (with a selectivity of 99 %). This observed enhancement is three times higher (HER = 1.60 mmol⋅g−1⋅h−1) than a discrete catalyst NaH2(TPA)[Ru8(CO3)4(CO)16Cl4]·EtOH·5H2O (HER = 0.48 mmol⋅g−1⋅h−1). Activity contrast experiments were conducted to gain insights into the photocatalytic reaction pathways, enabling the proposal of potential mechanisms that further elucidate the process. This research presents a significant expansion in the realm of designing and developing novel multifunctional artificial photocatalysts based on polyoxometalate (POMs) with enhanced electronic interactions. These advancements open up exciting possibilities for diverse economic and ecological photoredox applications.