Heteropolyacids-Immobilized Graphitic Carbon Nitride:Highly Efficient Photo-Oxidation of Benzyl Alcohol in the Aqueous Phase

• 作者: Lifu Wu Sai An Yu-Fei Song
• 来源期刊: 工程（英文）
• 年，卷（期）: 2021,（1）
• 所属期刊栏目: Frontiers of Chemical Engineering-Article
• 页码范围: 94-102
• 页数: 9页
• 语种: 英文

摘要

Benzaldehyde is a highly desirable chemical due to its extensive application in medicine,chemical syn-thesis and food sector among others.However,its production generally involves hazardous solvents such as trifluorotoluene or acetonitrile,and its conversion,especially selectivity in the aqueous phase,is still not up to expectations.Hence,developing an environmentally benign,synthetic process for benzalde-hyde production is of paramount importance.Herein,we report the preparation of a photocatalyst(PW12-P-UCNS,where PW12 is H3PW12O40·xH2O and P-UCNS is phosphoric acid-modified unstack graphi-tic carbon nitride)by incorporating phosphotungstic acid on phosphoric acid-functionalised graphitic carbon nitride(g-C3N4)nanosheets.The performance of PW12-P-UCNS was tested using the benzyl alco-hol photo-oxidation reaction to produce benzaldehyde in H2O,at room temperature(20℃).The as-prepared PW12-P-UCNS photocatalyst showed excellent photocatalytic performance with 58.3％conver-sion and 99.5％selectivity within 2 h.Moreover,the catalyst could be reused for at least five times with-out significant activity loss.Most importantly,a proposed Z-scheme mechanism of the PW12-P-UCNS-catalysed model reaction was revealed.We carefully investigated its transient photocurrent and electro-chemical impedance,and identified superoxide radicals and photogenerated holes as the main active spe-cies through electron spin-resonance spectroscopy and scavenger experiments.Results show that the designed PW12-P-UCNS photocatalyst is a highly promising candidate for benzaldehyde production through the photo-oxidation reaction in aqueous phase,under mild conditions.