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2021 2

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Benzaldehyde 1

Graphitic carbon nitride 1

Heteropolyacids 1

Photocatalysis 1

carbonylation 1

density functional theory 1

dimethyl ether 1

heteropolyacids 1

mechanism 1

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A density functional theory study on the mechanism of Dimethyl ether carbonylation over heteropolyacids

Kai Cai, Ying Li, Hongbao Shen, Zaizhe Cheng, Shouying Huang, Yue Wang, Xinbin Ma

Frontiers of Chemical Science and Engineering 2021, Volume 15, Issue 2, Pages 319-329 doi: 10.1007/s11705-020-1957-2

Abstract: Heteropolyacids (HPAs) are proved to be efficient catalysts for DME carbonylation.

Keywords： dimethyl ether carbonylation mechanism heteropolyacids density functional theory

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Heteropolyacids-Immobilized Graphitic Carbon Nitride: Highly Efficient Photo-Oxidation of Benzyl Alcohol Article

Lifu Wu, Sai An, Yu-Fei Song

Engineering 2021, Volume 7, Issue 1, Pages 94-102 doi: 10.1016/j.eng.2020.07.025

Abstract:

Benzaldehyde is a highly desirable chemical due to its extensive application in medicine, chemical synthesis 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 benzaldehyde production is of paramount importance. Herein, we report the preparation of a photocatalyst (PW₁₂-P-UCNS, where PW₁₂ is H₃PW₁₂O_40·xH₂O and P-UCNS is phosphoric acid-modified unstack graphitic 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 alcohol photo-oxidation reaction to produce benzaldehyde in H2O, at room temperature (20 °C). The asprepared PW₁₂-P-UCNS photocatalyst showed excellent photocatalytic performance with 58.3% conversion and 99.5% selectivity within 2 h. Moreover, the catalyst could be reused for at least five times without significant activity loss. Most importantly, a proposed Z-scheme mechanism of the PW₁₂-P-UCNScatalysed model reaction was revealed. We carefully investigated its transient photocurrent and electrochemical impedance, and identified superoxide radicals and photogenerated holes as the main active species 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.