Silicomolybdic acid intercalated graphene oxide-based solid acid: catalytic activity and investigation of structural stability by DFT analysis

Silicomolybdic acid supported graphene oxide (GO-SMA) was synthesized via a simple impregnation method and demonstrated as an active catalyst for the efficient synthesis of biologically important molecule (isoxazoles) under green and efficient microwave condition. The structural and morphological variation of the catalyst was investigated by a number of sophisticated characterization techniques. For the detection of acidic sites on GO-SMA surface, NH3-TPD and pyridine IR spectroscopic studies were carried out and revealed the presence of a significant amount of acidic sites (0.62 mmol g(-1)) which are essential for heterogeneous acid catalysis. A Density Functional Theory (DFT) method had revealed that our catalyst is thermodynamically stable as the binding energy was found to be (-56.28 kcal/ mol). Also, it was found that reactant molecules were efficiently adsorbed on the catalyst surface which enhanced the catalytic activity. Besides high catalytic activity and a wide variety of substrate scope this catalyst showed good recyclability up to five successive cycles with minimum loss of activity.

Automated summary

In this study, a silica-supported graphene oxide catalyst was synthesized and found to exhibit high catalytic activity, wide substrate scope, and good recyclability for the efficient synthesis of isoxazoles under green and efficient microwave conditions.