Extended H-bonds/π-bonds networks for boosting electron transfer over polydopamine-covered nanocellulose/g-C3N4 toward efficient photocatalytic H2O2 production

Photocatalytic hydrogen peroxide production (PHP) from H2O and O2 is a promising solar-to-chemical conversion technology. However, conventional doping, heterojunction and defect engineering of catalyst modification for enhanced PHP process is unable to meet the highly requirements of efficient oxygen reduction reaction (ORR), while also damaging the intrinsic crystal structure of the catalysts. Herein, we demonstrate a rationally extended H-bonds/π-bonds intermolecular networks between carbon nitride (g-C3N4, CN) and carboxylated cellulose nanofibers (CNF) with a small quantity of polydopamine (PDA) for solar H2O2 production. Ultimately, CN/CNFP exhibits an extraordinary PHP of 130.7 μmol·L−1·h−1, surpassing CN/CNF (75.2 μmol·L−1·h−1) and pure CN (20.1 μmol·L−1·h−1). Experimental and density function theory (DFT) have validated that CNFP increases the adsorption capabilities of O2, enhancing the efficiency of photogenerated charge transfer and separation via multiple hydrogen bonding/π-π stacking with g-C3N4, thereby facilitating the superior PHP via a two-step single-electron ORR pathway. This work offered a viable route to modulate directed transfer of photogenerated charges with multiple intermolecular interactions and presented an encouraging strategy to obtain high-efficient PHP. [Display omitted] •Polydopamine-covered cellulose nanofibers/g-C3N4 hybrid photocatalyst is prepared.•The CN/CNF composite photocatalyst enables efficient photocatalytic H2O2 generation.•PDA bridges CNF and CN leading to the formation of multiple hydrogen bonding and π-π stacking effect.•Rapid and smooth charge flow over the unique channels of hydrogen bonding/π-π stacking is thoroughly demonstrated.