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Effect of the V4+(3+)/V5+ ratio on the denitration activity for V2O5–WO3/TiO2 catalysts

“…NH 3 -TPD results of V 2 O 5 -WO 3 /TiO 2 catalysts were tested in order to investigate the influence of the oxygen amount on surface acidity in the calcination process. 34 For V3W8Ti(a) catalysts, these two kinds of desorption peaks were mainly due to the presence of low valence vanadium (V 4+ , V 3+ ) on the catalyst surface. 6(a) and Table 4, the desorption peaks in the range of 100-300 1C can be ascribed to the weak acidic sites which correspond to physisorbed ammonia and partially ionic NH 4 + bound to Brønsted acid sites.…”

“…32 In Fig. 15,34 The ammonia desorption peak at high temperature was assigned to Lewis acid sites from surface Ti-OH. 33 Desorption peaks appearing in the range of 400-500 1C are ascribed to the desorption of coordinated NH 3 bounded to Lewis acid sites.…”

“…[33][34][35] The rate equation is r = kc NO and the rate constant can be described as follows. To avoid the external diffusion effect, the steady-state condition experiments were carried out at a high space velocity of 300 000 h À1 in the temperature range of 100 to 300 1C.…”

Ammonia and water sorption properties of the mineral-layered nanomaterials used as the catalysts for NOx removal from exhaust gases

“…Additionally, the acidity of samples A-Zr, AH-Zr and AZrMnS9 was compared with the data published by Chmielarz et al [19]. The authors used the temperature programmed desorption of ammonia (the TPD method) after the NH 3 adsorption at 343 K.…”

Influence of calcination temperature on iron titanate catalyst for the selective catalytic reduction of NOx with NH3

“…As the NH 3 -TPD results shown in Fig. S4A, there were three groups of NH 3 desorption peaks detected over all samples, among which the peaks between 50 and 80 • C were attributed to the desorption of physisorbed NH 3 , the peaks between 100 and 130 • C to the desorption of NH 4 + bound to weak Brønsted acid sites [34,35], and the peaks above 200 • C to the multiple desorption of NH 4 + bound to strong Brønsted acid sites plus coordinated NH 3 bound to Lewis acid sites [36]. With the increasing of calcination temperature, the total desorption amount of NH 3 over FeTiO x serial catalysts showed an obvious and monotonic decrease, and the desorption ratio of NH 4 + bound to Brønsted acid sites also showed some decrease to a certain extent.…”