posted on 2021-08-25, 07:30authored bySifan Jia, Xin Shu, Hongyan Song, Zhe An, Xu Xiang, Jian Zhang, Yanru Zhu, Jing He
Selective dehydrogenation of ethanol
under mild conditions is of
great significance for the conversion of ethanol into high-value chemicals.
This work reports Au/anatase–rutile TiO2 photocatalysts
for the targeted activation of O–H and α–H bonds
and provides deep insights into the ethanol photocatalytic mechanism.
In situ EPR, in situ FT-IR, and XPS were performed on Au/anatase–rutile
TiO2 to explore the photocatalytic selective dehydrogenation
process of ethanol. Under UV irradiation, O–H and α–H
bonds of ethanol can be activated on TiO2 at the same time.
Detailed investigations verified that Au/rutile TiO2 dominates
the activation of O–H and facilitates the generated CH3CH2O• and CH3CH(OH)• diffused in the liquid phase for their subsequent
reaction to 1,1-diethoxyethane (DEE). While radicals formed on Au/anatase
TiO2 can not only react directly for DEE formation, they
can also further dehydrogenate to acetaldehyde due to the strong adsorption
on the surface of the catalyst and then produce DEE by condensation
with ethanol. Au nanoparticles distributed at the anatase–rutile
TiO2 interface show a significant electron–hole
separation efficiency; therefore, the photocatalytic activity of ethanol
selective dehydrogenation was improved. This study is of vital importance
to the understanding of the reaction mechanism of photocatalytic ethanol
conversion.