Boosting acetone oxidation performance over mesocrystal MxCe1-xO2 (M = Ni, Cu, Zn) solid solution within hollow spheres by tailoring transition-metal cations

Abstract

Developing mesocrystal bimetal oxide solid solutions with distinctive architectures applied for VOCs elimination is of significant importance towards environmental catalysis. Herein, mesocrystal MxCe1-xO2 (M = Ni, Cu, Zn) solid solution within hollow spheres has been readily synthesized via a facile solvothermal strategy, primarily aiming to boost catalytic acetone oxidation performance by tailoring transition-metal cations. The physicochemical properties of the synthesized mesocrystal catalysts have been analyzed using various means of characterizations and correlated with their catalytic acetone oxidation performances. Research results evidence that the catalytic acetone oxidation performance ranked in the order of CeO2 < Ni0.015Ce0.985O2 < Zn0.015Ce0.985O2 < Cu0.015Ce0.985O2, in which Cu0.015Ce0.985O2 indeed acted as the optimal catalyst that completely achieved 100% CO2 selectivity and 100% acetone conversion at 210 °C under test conditions of 20 vol%O2, 80 vol%N2 as the balance gas, WHSV = 90,000 mL/gcat·h and 1000 ppm acetone. This fact can be mainly credited to the intrinsic discrepancy of transition-metal cations that resulted in different numbers of defective sites and active oxygen species together with varied reducible capabilities. Meanwhile, all synthesized mesocrystal catalysts exhibit both excellent long-term stabilities and strong water tolerances, mainly due to the integrated factors of the mesocrystal feature together with stable crystal phase meliorating thermal stability and the robust hollow spherical architecture suppressing structural collapse, demonstrating great potentials towards VOCs elimination.