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

Photo-driven H2O2 production by graphitic carbon nitride (g-C3N4) using H2O and O2 is a sustainable alternative to fossil fuels, but pristine g-C3N4 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 H2O2 synthesis, while also damaging the intrinsic crystal structure of the catalysts. Herein, a "living" aldehyded cellulose nanofibers (CNFA) are anchored onto g-C3N4 with multiple hydrogen and covalent bonding. Moreover, the CNFA incorporation is found to dominantly increase the wettability of g-C3N4 and promote the adsorption of molecular oxygen. Batch experiments and DFT calculations further confirm that high-quality interfacial hydrogen and covalent bonding between CNFA and g-C3N4 with boosting transfer of photogenerated electrons, leading enhanced single-electron oxygen reduction reaction (ORR) for H2O2 generation. The optimized photocatalytic H2O2 of resultant MCN-CNFA 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-C3N4-based photocatalysts for H2O2 generation.