Room-Temperature Nitrophenol Reduction over Ag–CeO2 Catalysts: The Role of Catalyst Preparation Method

Abstract

Ag–CeO2 catalysts (20 mol % Ag) were synthesized using different techniques (co-precipitation, impregnation, and impregnation of pre-reduced ceria), characterized by XRD, N2 sorption, TEM, H2-TPR methods, and probed in room-temperature p-nitrophenol reduction into p-aminophenol in aqueous solution at atmospheric pressure. The catalyst preparation method was found to determine the textural characteristics, the oxidation state and distribution of silver and, hence, the catalytic activity in the p-nitrophenol reduction. The impregnation technique was the most favorable for the formation over the ceria surface of highly dispersed silver species that are active in the p-nitrophenol reduction (the first-order rate constant k = 0.656 min−1).

Silver/silver halide supported on mesoporous ceria particles and photo-CWPO degradation under visible light for organic compounds in acrylonitrile wastewater

“…The loading of Ag does not change the mesoporous structure of CeO 2 . 25 From Fig. 1b , compared with the characteristic diffraction peaks of Ag (JCPDS no.…”

“…That's because only H 2 O 2 is added as oxidant in system (d), and the oxidation potential of H 2 O 2 is 1.78 eV, while the oxidation potential of ˙OH is 2.8 eV. 34 Therefore, the oxidizability of H 2 O 2 is weaker than that of ˙OH. The irradiation of visible light can not make H 2 O 2 produce enough ˙OH, moreover, visible light can decompose H 2 O 2 into H 2 O and O 2 , which reduces the utilization of H 2 O 2 and leads to the worst COD removal.…”

“…lowest. That's because only H 2 O 2 is added as oxidant in system (d), and the oxidation potential of H 2 O 2 is 1.78 eV, while the oxidation potential of cOH is 2.8 eV 34. Therefore, the oxidizability of H 2 O 2 is weaker than that of cOH.…”

Catalytic wet peroxide degradation of acrylonitrile wastewater by ordered mesoporous Ag/CeO2: synthesis, performance and kinetics

“…Also some scholars have successfully synthesized Ag/CeO 2 catalysts. [36][37][38] Most of them were prepared by hydrothermal or coprecipitation methods, and the Ag/CeO 2 prepared was used for catalytic degradation of p-nitrophenol, 36 naphthalene, 39 formaldehyde, 40 propene, 41 etc. Therefore, it is necessary to further study the application potential of Ag/CeO 2 in catalytic degradation of organic compounds.…”

“…The interaction between Ag and CeO 2 is that Ag species contribute valence electrons to CeO 2 as electron donors, and CeO 2 is reduced by electron acceptor, and oxygen on CeO 2 surface will also reverse ow to Ag nanoparticles. Ag doping increases the oxygen defects in CeO 2 lattice and increases the concentration of adsorbed oxygen on the surface 51. The oxygen defect of CeO 2 can stabilize the oxidation state of Ag species and improve the redox ability of Ag/CeO 2 .Catalytic wet peroxide performance 0.4-Ag/CeO 2 , 0.8-Ag/CeO 2 , 1.0-Ag/CeO 2 and CeO 2 were selected as catalyst to compare their catalytic performance.…”