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

Abstract

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 O₂ 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 μmol g⁻¹ h⁻¹, which are higher than that of pristine CNF (72.3 μmol 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.