Synergistic Generation of Radicals by Formic Acid/H₂O₂/g-C₃N₄ Nanosheets for Ultra-efficient Oxidative Photodegradation of Rhodamine B

Abstract

Water pollution is a global challenge endangering people's health. In this work, an ultra-efficient photodegradation system of Rhodamine B (RhB) has been established using a graphitic carbon nitride nanosheet (CNNS) as the semiconductor photocatalyst, from which energy is harvested on both the conduction band and valence band by formic acid and hydrogen peroxide, respectively. The optimized FA/H 2 O 2 /CNNS system increases the apparent photodegradation rate of RhB by 25 folds, from 0.0198 to 0.4975 min −1 . Through a comprehensive investigation with reactive oxygen species scavengers, electron paramagnetic resonance, high-performance liquid chromatography−mass spectrometry, etc., an oxidative mechanism for RhB photodegradation has been proposed, which combines enhanced charge carrier migration and synergistic generation of multiple radicals. Comparable performance improvements have also been observed for similar systems with different semiconductors, suggesting that such a catalytic system could afford a general approach to enhance semiconductor−catalyzed photodegradation.

Nanoarchitectonics of g-C3N4 Nanosheets with a AuCu Enhancement Effect for Superior Photo- and Electrochemical Activity

“…Mott− Schottky plots were also measured to obtain the band gap structures, as shown in Figure S5. 52 The flat potentials of samples were CN = −1.05 eV, Cu/CN = −1.12 eV, Au/CN = −1.13 eV, and AuCu/CN-1% = −1.18 eV, respectively. Thus, the conduction band (CB) positions were obtained by the equation of a normal hydrogen electrode…”

“…On the other hand, the separation efficiency of photoinduced carriers was enhanced to promote the photocatalytic reaction. Mott–Schottky plots were also measured to obtain the band gap structures, as shown in Figure S5 . The flat potentials of samples were CN = −1.05 eV, Cu/CN = −1.12 eV, Au/CN = −1.13 eV, and AuCu/CN-1% = −1.18 eV, respectively.…”