Anchoring Active Pt /Pt Hybrid Nanodots on g-C N Nitrogen Vacancies for Photocatalytic H Evolution.

A Pt /Pt hybrid nanodot-modified graphitic carbon nitride (CN) photocatalyst (CNV-P) was fabricated for the first time using a chemical reduction method, during which nitrogen vacancies in g-C N assist to stabilize Pt species. It is elucidated that the coexistence of metallic Pt and Pt species in the Pt nanodots loaded on g-C N results in superior photocatalytic H evolution performance with very low Pt loadings. The turnover frequencies (TOFs) are 265.91 and 116.38 h for CNV-P-0.1 (0.1 wt % Pt) and CNV-P-0.5 (0.5 wt % Pt), respectively, which are much higher than for other g-C N -based photocatalysts with Pt co-catalyst reported previously. The excellent photocatalytic H evolution performance is a result of i) metallic Pt facilitating the electron transport and separation and Pt species preventing the undesirable H backward reaction, ii) the strong interfacial contact between Pt /Pt hybrid nanodots and nitrogen vacancies of CNV facilitating the interfacial electron transfer, and iii) the highly dispersed Pt /Pt hybrid nanodots exposing more active sites for photocatalytic H evolution. Our findings are useful for the design of highly active semiconductor-based photocatalysts with extremely low precious metal content to reduce the catalyst cost while achieving good activity.