LAUSR

Significance Single-atom or single-site catalysts have received considerable research interest in photocatalysis and many other heterogeneous catalytic processes. However, the single metal sites did not obviously change the charge transportation process of the photocatalyst and thus hardly contributed to the enhancement of charge separation and transfer. Inspired by the synergy between metal species in classical catalytic reactions, this research presents a strategy of constructing a Pt-Au binary single-site catalyst. Pt-Au binary single sites not only functioned as the catalytic reactive sites but also modulated the charge distribution and enhanced the internal electric field. The concept and the strategy of this work are expected to provide a novel perspective for improving photocatalytic charge transportation dynamics. Solar water splitting is regarded as holding great potential for clean fuels production. However, the efficiency of charge separation/transfer of photocatalysts is still too low for industrial application. This paper describes the synthesis of a Pt-Au binary single-site loaded g-C3N4 nanosheet photocatalyst inspired by the concept of the dipole. The existent larger charge imbalance greatly enhanced the localized molecular dipoles over adjacent Pt-Au sites in contrast to the unary counterparts. The superposition of molecular dipoles then further strengthened the internal electric field and thus promoted the charge transportation dynamics. In the modeling photocatalytic hydrogen evolution, the optimal Pt-Au binary site photocatalysts (0.25% loading) showed 4.9- and 2.3-fold enhancement of performance compared with their Pt and Au single-site counterparts, respectively. In addition, the reaction barrier over the Pt-Au binary sites was lowered, promoting the hydrogen evolution process. This work offers a valuable strategy for improving photocatalytic charge transportation dynamics by constructing polynary single sites.