High-efficiency photoelectrochemical seawater splitting by tuning the semi-embedded surface of SMSI systems

Strong Metal-Support Interactions (SMSI) are recognized as a crucial aspect of tuning catalytic activity. Here we report the remarkable effectiveness of SMSI between Mn:BiVO 4 supports and semi-embedded Pt nanoparticles (NPs) (Pt/Mn:BiVO 4 -SMSI) in enhancing photoelectrochemical (PEC) water splitting. The incorporation of Mn greatly reduces the polaron jumping barriers and passivates the surface trap states. Due to the SMSI, electrons are transferred from the V 4+ to the Pt NPs, resulting in the construction of electron-rich Pt species (Pt δ– ) and semi-embedded interfaces (Pt δ– –O V –VO x ), which contributes to the extraction of photoinduced holes and shorten the charge transport distances. Benefiting from the SMSI effect, the as-obtained Pt/Mn:BiVO 4 -SMSI composite photoelectrode shows an excellent photocurrent density of 4.47 mA‧cm −2 at 1.23 versus the reversible hydrogen electrode in conventional electrolytes. Importantly, for PEC seawater splitting, VO x Lewis acid protective layer can tune the surface micro-catalytic environment. It enables the capture of OH − ions and resists surface Cl − to inhibit the chlorine attack on the photoelectrode. Such an in-situ generated microenvironment avoids the formation of precipitates. As a result, the Pt/Mn:BiVO 4 -SMSI exhibits an superior stability in both simulated seawater and natural seawater, respectively. This work sheds new light on the design of efficient photoanodes for PEC seawater splitting.