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-C 3 N 4 ) through the amidation reaction. The hybrid catalyst of g-C 3 N 4 -CNTs with well-defined and stable structure exhibits efficient catalytic performance (32.6 μmol h −1 ) for photocatalytic H 2 O 2 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-C 3 N 4 -CNTs (n = 1.96) is higher than that for g-C 3 N 4 (n = 1.29), suggesting that the CNTs covalent combined with g-C 3 N 4 can promote the electrons generation. The p -benzoquinone (PBQ) scavenger experiments, the electron spin resonance (ESR) signal and quantitative experiment of O 2 − results reveal that the negative shifts of the conduction band (CB) level from g-C 3 N 4 to g-C 3 N 4 -CNTs can enhance the single-electron reduction of O 2 to O 2 − and further promote the sequential two-step single-electron O 2 reduction reaction to H 2 O 2 . [ABSTRACT FROM AUTHOR]