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Mechanism of UV ‐driven Photoelectrocatalytic Degradation of Berberine Chloride Form Using the ESR Spin‐trapping Method
Author(s) -
Liu Rong,
Zhang Yonggang
Publication year - 2018
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12907
Subject(s) - spin trapping , chemistry , radical , electron paramagnetic resonance , photocatalysis , photochemistry , anatase , catalysis , degradation (telecommunications) , chloride , reactive oxygen species , adduct , rutile , oxygen , organic chemistry , biochemistry , telecommunications , physics , nuclear magnetic resonance , computer science
Photoelectrocatalytic ( PEC ) system greatly improves the migration of photoexcited charges, retards the fast recombination of electron‐hole and increases the lifetime of photogenerated holes. In this article, we constructed a novel PEC system to degrade berberine chloride form ( BCF ). XRD patterns indicated aging time was an important condition for the crystal type of TiO 2, and the best proportion of anatase/rutile was 80/20. The band gap energy of the TiO 2 was 3.01 eV . We demonstrated that a synergistic effect existed between photocatalysis ( PC ) and electrocatalysis ( EC ). Besides, we discussed the influence of pH , current density, the amount of catalyst and initial BCF concentration on the degradation of BCF . Electron spin resonance ( ESR ) through spin trap 5, 5‐dimethyl‐1‐pyrroline‐N‐oxide ( DMPO ) and the scavenging experiments suggested that the reactive oxygen species ( ROS ) were superoxide radicals ( O 2 · − ), hydroxyl radicals (· OH ) and sulfate radical ( SO 4 · − ) in PEC system. Furthermore, we compared the two pathway of formation DMPO ‐ SO 4 adducts and found that SO 4 · −was the most major oxidized species in degrading BCF . We proposed a plausible reaction mechanism. Intriguingly, even under lower current and weaker light conditions, the PEC process maintained its effectiveness, demonstrating the feasibility of the PEC approach.