Carbon nanotubes covalent combined with graphitic carbon nitride for photocatalytic hydrogen peroxide production under visible light

The carbon nanotubes (CNTs) have been combined with graphitic carbon nitride (g-C3N4) through the amidation reaction. The hybrid catalyst of g-C3N4-CNTs with well-defined and stable structure exhibits efficient catalytic performance (32.6 mu mol h(-1)) for photocatalytic H2O2 production in the presence of formic acid under visible light. The value of electron transfer during the oxygen reduction reaction (ORR) process obtained from the Koutecky-Levich plot for g-C3N4-CNTs (n = 1.96) is higher than that for g-C3N4 (n = 1.29), suggesting that the CNTs covalent combined with g-C3N4 can promote the electrons generation. The p-benzoquinone (PBQ) scavenger experiments, the electron spin resonance (ESR) signal and quantitative experiment of center dot O-2(-) results reveal that the negative shifts of the conduction band (CB) level from g-C3N4 to g-C3N4-CNTs can enhance the single electron reduction of O-2 to center dot O-2(-) and further promote the sequential two-step single-electron O-2 reduction reaction to H2O2.