DFT assisted study on activation of surface acidic –COOH debris in graphene oxide supported catalyst for benzyl alcohol oxidation

Abstract

This study is aimed to elucidate the deep intuitive understanding of whether carboxyl groups of graphene oxide (GO) are worth modifying for the selective oxidation of benzyl alcohol (BzA) to benzaldehyde (BzH). In this work, for the first time, Cu-salen complex (Where Salen = N,N’-bis(4-hydroxysalicylaldehyde)ethylenediamine) was grafted on chloro- modified GO nanosheets forming a heterogeneous catalyst (Cu-f-GO). First principles-based density functional theory (DFT) has been performed to inspect structural and electronic properties, binding mechanism of SOCl2 with each available functional group of GO. Besides, other parameters like HOMO, LUMO, energy bandgap (Eg), adsorption energy (Ead), electronegativity (χ), chemical potential (μ), and global electrophilicity were also calculated. The catalytic results show that the as-prepared catalyst demonstrated petite performance. This poor performance might be due to lesser acidic sites available on the surface of the catalyst. Hence, it was decided to substantiate the hypothesis, we have conducted the catalytic reaction using a few drops of concentrated H2SO4 as a precursor. The use of precursor had resulted in optimal activity with 100% conversion and 98.64% selectivity to BzH within 1 h.