DYE-CATALYST INTERACTIONS IN A WATER-SPLITTING SYSTEM: A FIRST-PRINCIPLES INVESTIGATION OF INTERFACIAL STRUCTURES BASED ON COUMARIN343/[FeFe](mcbdt)(CO) 6 /NiO

Organic dyes and molecular catalysts co-adsorbed on a metal oxide substrate are widely employed for water-splitting photoelectrodes. In this manuscript, we employ first-principles calculations to investigate interactions between a coumarin dye and a molecular catalyst on the nickel oxide substrate in an experimentally verified water-splitting photocathode. The nanoscopic interfacial structures and interfacial charge transfer properties of dye/catalyst/metal oxide hybrid systems in the water-splitting photocathode are elucidated. In particular, the intermolecular hydrogen bond and the substrate-to-catalyst electron transfer stabilize the interfacial structure. The present study helps the fundamental understanding of water-splitting photoelectrodes co-adsorbed with organic dyes and molecular catalysts.