ABSTRACT Coupling photocatalytic H 2 evolution with biomass valorization offers a sustainable route to simultaneously produce clean fuel and high‐value chemicals, yet realizing efficient charge separation and precise redox stoichiometry remains a formidable challenge. Herein, a robust 0D/2D S‐scheme heterojunction is orchestrated by anchoring Mn 0.3 Cd 0.7 S nanoparticles onto KNCN (K‐doped and cyano‐deficient carbon nitride) nanosheets via a self‐assembly strategy. Experimental and theoretical investigations reveal that the synergistic introduction of alkali‐metal dopants and cyano defects modulates the Fermi level of the carbon nitride matrix, significantly enlarging the work function difference at the heterointerface. Kelvin probe force microscopy (KPFM) spatially visualizes a fortified built‐in electric field (IEF), which acts as a powerful driving force to steer charge kinetics through an efficient S‐scheme pathway. Consequently, the optimal heterojunction delivers a remarkable H 2 evolution rate of 291.43 µmol g −1 h −1 (6.2‐fold enhancement over the pristine counterpart) coupled with the selective oxidation of vanillyl alcohol to vanillin (> 94% selectivity). Notably, a near‐unity (1:1) stoichiometric ratio of H 2 to vanillin is achieved, highlighting superior atom economy. This work not only unravels the origin of the enhanced IEF, but also provides a paradigm for designing precise dual‐functional photocatalytic systems for solar‐to‐chemical conversion.
Dai et al. (Fri,) studied this question.