Facile synthesis of O-doped carbon nitride nanofibers for two-step single-electron oxygen reduction to H₂O₂

Elemental doping is an effective and attractive method for improving the photocatalytic performance. Here we synthesized three types of O-doped carbon nitride nanofibers (ACN, CCN, and LCN) through a one-pot simple solvothermal process by using l-arginine, l-cysteine and l-lysine as O dopants into pristine carbon nitride nanofibers (CNF). The three O-doped samples exhibited enhanced light harvesting capacity and satisfactory O-2 adsorption and activation ability, which is beneficial for the following H2O2 generation process. The photocatalytic H2O2 generation rates of the optimal ACN, CCN, and LCN samples are 156.9, 166.2 and 107.2 mu mol g(-1) h(-1), which are higher than that of pristine CNF (72.3 mu mol g(-1) h(-1)). Especially, CCN shows an apparent quantum efficiency of 4.66% at 420 nm. The results of photocurrent measurements and photoluminescence spectra indicate that the charge carrier recombination was effectively inhibited in the O-doped samples. Our research provides an effective and environmentally friendly strategy to improve the H2O2 generation performance by using common compounds in human life.