Anchoring active Pt2+/Pt0 hybrid nanodots on g-C3N4 nitrogen vacancies for photocatalytic H2 evolution

Abstract

A Pt2+/Pt0 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‐C3N4 assist to stabilize Pt2+ species. It is elucidated that the coexistence of metallic Pt0 and Pt2+ species in the Pt nanodots loaded on g‐C3N4 results in superior photocatalytic H2 evolution performance with very low Pt loadings. The turnover frequencies (TOFs) are 265.91 and 116.38 h−1 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‐C3N4‐based photocatalysts with Pt co‐catalyst reported previously. The excellent photocatalytic H2 evolution performance is a result of i) metallic Pt0 facilitating the electron transport and separation and Pt2+ species preventing the undesirable H2 backward reaction, ii) the strong interfacial contact between Pt2+/Pt0 hybrid nanodots and nitrogen vacancies of CNV facilitating the interfacial electron transfer, and iii) the highly dispersed Pt2+/Pt0 hybrid nanodots exposing more active sites for photocatalytic H2 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.