Selective catalytic oxidation of ammonia to nitrogen over CuO-CeO2 mixed oxides prepared by surfactant-templated method

Copper as promoter of the NiO–CeO 2 catalyst in the preferential CO oxidation

“…These applications include solid electrolytes in solid oxide fuel cells, oxygen sensors, ultraviolet absorbers, automotive three-way catalysts and catalytic support [2]. Many studies have shown that these redox properties can be considerably enhanced if other metals are introduced into the CeO 2 lattice by forming solid solution [3][4][5][6][7][8]. In addition, CeO 2 still shows oxygen vacancies in the ceria crystal structure after Ni doping as well as to the presence of highly dispersed nickel species on its surface [13,14].…”

“…However, Ni-containing catalysts have a tendency to catalyze undesired reaction of hydrogenation of CO 2 and CO with consequent formation of methane, besides being prone to coke formation [15]. Importantly, some studies have shown that both the deactivation by coke deposition and the suppression of undesired side reactions can be considerably enhanced if a promoter is introduced along with Ni-based ceria systems [4,16]. Among them, copper (Cu) atoms have a great advantage mainly because of its qualities, such as: catalytic stability, low cost and excellent catalytic performance [8,[17][18][19][20].…”

Copper based catalysts for the selective ammonia oxidation into nitrogen and water vapour—Recent trends and open challenges

“…This type of catalysts showed higher selectivity to N2, however, they need significantly higher operation temperatures as high as 300-500C, than noble metal catalysts. For pure rare earth oxides, such as ceria, the catalytic activity was quite poor, with not satisfying selectivity to N2 [97,100]. Better results were achieved over cerium composite catalysts, but still operating at temperatures above 400C is necessary [e.g.…”

“…In this line, CuO-CeO2 mixed metal oxides have been selected and applied in ammonia oxidation [97,101,139], mainly due to the high efficiency of cerium based materials in various other environmental catalytic processes, such as NO reduction [e.g. 140], CO oxidation [e.g.…”

Influence of attrition milling on V/Ti catalysts for the selective oxidation of ammonia

“…Kwon et al [20] reported an increase in the V/Ti ratio of the catalyst surface due to milling, which means that the acid sites increase as vanadium becomes more highly dispersed on the catalyst surface due to attrition milling. Wang et al [29] demonstrated that a high intensity peak is generated in the NH 3 -TPD profile of finely dispersed metal oxide species on the catalyst surface, and that the finely dispersed metal oxide species are the main sites of adsorption of NH 3 molecules. The amount of ammonia adsorbed is related to the active sites exposed on the surface and the surface area of the catalyst.…”