Hydrogen-bonds bridged biomass-assisted S-scheme junction boosts proton-coupled electron transfer for H2O2 photosynthesis

Artificial photosynthesis offers a sustainable route for hydrogen peroxide (H 2 O 2 ) production, yet its practical efficacy is heavily constrained by two pivotal challenges: the photogenerated charges undergo rapid recombination and oxidation reaction (ORR) proceeds with sluggish kinetics. S-scheme heterojunctions address the first challenge by enhancing charge separation, but their H 2 O 2 production remains limited by inefficient proton transfer that restricts the critical proton-coupled electron transfer (PCET), process underlying ORR. To overcome this remaining limitation, the introduction of carboxyl-functionalized cellulose nanofibril (f-CNF), synergizes the intrinsic merits of biomass-derived materials with enhanced proton-donating capability and tailored interfacial interactions, thereby promoting PCET and resolving the inefficient proton supply of S-scheme heterojunctions. Herein, we exhibit a hydrogen-bonding network via engineering CdS/g-C 3 N 4 (CdS/PCN) S‐scheme heterojunction with f-CNF molecular for non-sacrificial H 2 O 2 production through accelerated PCET process. In pure water systems, the catalyst presents an exceptional photocatalytic activity of 2867 μmol L −1 h −1 , which is superior to state-of-the-art photocatalysts. The impressive performance is primarily ascribed to the synergistic effect arising from the CdS/PCN S-scheme mechanism and the molecular engineering of biomass-derived CNFs, which collectively boost the supplement and combination of electrons and protons, lower the reaction energy barrier of *OOH intermediate, and accelerate the conversion of superoxide conversion. This significantly accelerates the PCET process for further superior H 2 O 2 photosynthesis. This breakthrough supplies a perspective to markedly elevate photocatalytic performance and bears substantial implications for the sustainable, large-scale photosynthetic production of H 2 O 2 . • A hydrogen-bonding network was constructed by engineering CdS/PCN with f-CNF. • The catalyst exhibited a high photocatalytic activity of 2867 μmol L −1 h −1 in pure water. • The synergistic effect arises from the CdS/PCN S-scheme mechanism and molecular engineering of CNFs. • Synergistic effect accelerates PCET process, enabling superior H 2 O 2 photosynthesis.