Multiple covalent/hydrogen bonds bridging electron transfer in polymeric carbon nitride for efficient photocatalytic H2O2 production.

[Display omitted] • Aldehyded cellulose nanofibers/g-C 3 N 4 composite photocatalyst is fabricated. • The MCN-CNF A composite photocatalyst enables efficient photocatalytic H 2 O 2 production. • The multiple covalent/hydrogen bonds between MCN and CNF A is formed. • The electron transfer over the unique bridges of the multiple covalent/hydrogen bonds is thoroughly demonstrated. Photo-driven H 2 O 2 production by graphitic carbon nitride (g-C 3 N 4) using H 2 O and O 2 is a sustainable alternative to fossil fuels, but pristine g-C 3 N 4 is typically limited by inefficient charge transfer and separation. Many research works have focused on the construction of catalyst heterojunction, doping and defect engineering with electron migration for enhanced H 2 O 2 synthesis, while also damaging the intrinsic crystal structure of the catalysts. Herein, a "living" aldehyded cellulose nanofibers (CNF A) are anchored onto g-C 3 N 4 with multiple hydrogen and covalent bonding. Moreover, the CNF A incorporation is found to dominantly increase the wettability of g-C 3 N 4 and promote the adsorption of molecular oxygen. Batch experiments and DFT calculations further confirm that high-quality interfacial hydrogen and covalent bonding between CNF A and g-C 3 N 4 with boosting transfer of photogenerated electrons, leading enhanced single-electron oxygen reduction reaction (ORR) for H 2 O 2 generation. The optimized photocatalytic H 2 O 2 of resultant MCN-CNF A is 67.44 μmol/L, surpassing four-folds of pristine MCN. This work provides an eco-friendly design of active cellulose nanofibers, which efficiently tunes the intramolecular charge transfer of g-C 3 N 4 -based photocatalysts for H 2 O 2 generation. [ABSTRACT FROM AUTHOR]