Carbon‐Dot‐Mediated Highly Efficient Visible‐Driven Photocatalytic Hydrogen Evolution Coupled with Organic Oxidation

Abstract

AbstractPhotocatalytic hydrogen evolution coupled with organic oxidation reaction is a promising alternative to water splitting, where the efficiency is limited due to the weak correlation between charge separation and surface redox reactions. Here, employing nickel phthalocyanine (NiPc) for hole extraction, NiPc‐modified carbon dots (CDs) are combined with Cu–In–Zn–S quantum dots (CIZS QDs) toward a profound understanding of electron/hole extraction and surface proton generation and reduction. The optimal hydrogen evolution rate reaches 4.10 mmol g−1 h−1 for CIZS/NiPc–CDs with l‐ascorbic acid for hole consumption, 8.10 times to that of CIZS QDs, which is further promoted to 11.12 mmol g−1 h−1 under electron/hole coextraction with Ni2+ introduction. For benzyl‐alcohol‐oxidation‐coupled H2 evolution, this strategy shows a more dramatic activity enhancement (19.54 times), which is also appliable to methanol‐ or furfuryl‐alcohol‐oxidation coupling systems with state‐of‐the‐art activities. Transient photovoltage spectroscopy and apparent kinetics analysis indicate, for the first time, a light‐induced electrocatalysis effect consistent with the Volmer–Heyrovsky process, which establishes a quasiquantitative basis for balancing charge extraction and surface reactions.