NO reduction with CO on alumina-modified silica-supported palladium and molybdenum-palladium catalysts

Palladium and Molybdenum Mono and Bimetallic Catalysts on Modernite for Direct NO Decomposition Reaction

“…Comparing with previous work on NaY [20], mordenite catalysts has analogous activities than the catalyst supported on NaY (1.26% Pd prepared by dry impregnation) but better selectivities to N 2 and O 2 , since the selectivities to N 2 O were lower than in the NaY catalyst. The role of Mo was related previously to the metal capability of adsorbing and dissociating NO [12]. In this work, this second metal acts in a different way in the two catalysts: when this metal is present in lower amounts and was incorporated before Pd, the activity of the catalyst increases but not the selectivity.…”

“…It is worth mentioning that Pd is not only active for NO x reduction, but also for CO and hydrocarbons oxidation. In previous works, we have prepared mono-and bimetallic palladium catalysts using different materials as supports such as alumina [19], MCM-41 [11,12] and zeolite NaY [20]. Furthermore, we have studied mordenite as a support for Pd and Cu catalysts [13,14].…”

“…The selective reduction of NO x using CO [7], CH 4 [8] and C 3 H 6 [9] as reducting agents, and the direct NO decomposition reaction [10][11][12][13][14], represent a suitable alternative for the decomposition of these contaminant gases; in particular the direct NO decomposition since the process does not require a reducing agent. After the finding that a Cu-ZSM-5 catalyst was able to directly decompose NO, the study of different metals and supports has expanded with the ultimate goal of understanding and improving the catalytic performance [6,10].…”

A DFT study of the NO dissociation on gold surfaces doped with transition metals

“…Furthermore, other catalysts based on noble metals dispersed on a support were also tested for the NO x elimination 6,7 as those based on Ru, 8 Rh, 9 Ir, [10][11][12] Pd, [13][14][15] Pt, [16][17][18][19][20][21][22] Au, [23][24][25][26] Ag, [27][28][29][30] and also on alloys of these metals with cheaper metals. 8,9,20,22,31,32 In some cases the noble metal was successfully replaced by other elements. [33][34][35][36][37] Two general methods are used for the elimination of the NO x species from the exhaust gas emissions employing solid catalysts, (i) the Selective Catalytic Reduction (SCR) 38 and (ii) the NO x Storage-Reduction (NSR), 39,40 respectively, used for stationary and for non-stationary NO x sources.…”

“…Fax: +351 234 401 470. the catalyst's nature. 6,8,13,25,26 Formation of N 2 O during the NO x reduction reaction is also possible, and catalysts are optimized to minimize its formation, 19,31,41,42 or its reduction to molecular nitrogen. 10,17,29,43 One of the intermediates observed in the reduction of NO with CO is NCO, suggesting NO dissociation followed by reaction of an N adatom with CO. Interestingly, the NCO intermediate was not observed during the NO adsorption on Au/TiO 2 ; [44][45][46][47] but the formation of dinitrosyl complexes attached to the same Au atom, e.g., Au(NO) 2 species, either in the presence or in the absence of CO, 44,45 was detected.…”