Efficient Ag/CeO2 catalysts for CO oxidation prepared with microwave-assisted biosynthesis

•Rapid biosynthesis of Ag NPs employing leaf extract and microwave was developed.•Ag/CeO2 catalyst in this work exhibited comparable activity to reported ones.•Active components in leaf extract were identified and validated.•Effect of biomass on catalytic activity was investigated and discussed.

In this paper, we report a microwave-assisted biosynthesis method with Cinnamomum camphora (CC) leaf extract for the green and rapid synthesis of Ag nanoparticles (NPs). The as-produced Ag nanoparticles were immobilized onto CeO2 as supported Ag/CeO2 catalyst, which proved to be efficient for carbon monoxide (CO) oxidation. Active components in the plant extract were identified by FTIR analysis and later on validated through simulated experiments. The results revealed that polyphenols and proteins were the reducing and protecting agents, respectively. The optimum preparation conditions for the catalyst were irradiation time of 140 s, Ag loadings of 5 wt.%, CC extract concentration of 25 g L−1 and sintering temperature of 300 °C. Since biomolecules adsorbed over the surface of catalyst was detrimental to its catalytic activity, calcination to remove the biomolecules was critical to the enhanced activity. Considering the trade-off between particle size and biomass removal extent, the optimum calcination temperature was determined to be 300 °C.

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