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Copper-modified mesoporous MCM-41 silica: FTIR and catalytic study

“…They differ essentially in their thermodynamics [30,78] and could be favored to different extents depending on the catalyst peculiarities [17,19,[21][22][23][24][27][28][29][30]34,44]. The catalyst preparation method is a promising way of regulating different reaction pathways but more information on the nature of the active sites and their specific catalytic behavior is needed.…”

“…In the case of copper-containing catalysts the literature data concerning the role of various copper species in this process are rather controversial. Usually the participation of metallic copper is reported [11][12][13]16,[18][19][20][23][24][25][26]32,33,42,45,46] but the role of copper ions in this process is not completely clear [12,14,17,21,22,28,29,31,43,44,47,48]. In our previous studies [79][80][81][82][83][84], the nature of a catalytic active complex (CAC) of copper modified activated carbon in methanol decomposition has been discussed.…”

“…However, despite the great number of papers dealing with the mechanism of methanol dehydrogenation [36][37][38][39][40][41][42][43][44][45][46][47][48], the problem concerning its selectivity regulation is not fully solved. The selectivity is essentially affected by the acid-basic properties of the support [21][22][23][24]27], copper oxidation state and dispersion [19,29,42] and the type of copper precursor used [15,27]. Higher MF selectivity is usually observed with lower methanol conversion, but a significant selectivity decrease with temperature rise and flow rate decrease is also established [9,13,26,30,35,42,46,49].…”

Phase composition and catalytic properties in methanol decomposition of iron–ruthenium modified activated carbon

“…Obviously, the proper choice of a catalyst is of utmost importance for the process. Copper containing materials are usually proposed as suitable catalysts for methanol decomposition to CO, MF and H 2 [7][8][9][10][11][12][13][14][15]. Our previous studies revealed that the activity, stability and selectivity of methanol decomposition to CO or MF on catalysts of such as copper oxide supported activated carbon (AC) or mesoporous molecular sieves are strongly dependent on the method of catalyst preparation [16][17][18][19][20].…”

“…Our previous studies revealed that the activity, stability and selectivity of methanol decomposition to CO or MF on catalysts of such as copper oxide supported activated carbon (AC) or mesoporous molecular sieves are strongly dependent on the method of catalyst preparation [16][17][18][19][20]. Attempts have been made to elucidate the nature of the active sites in these systems [16][17][18][19] as far as the problem is still discussed in the literature [7][8][9][10][11][12][13][14][15][21][22][23][24][25][26][27][28][29][30]. It has been shown as well that the nanoparticles of iron or iron oxide supported on mesoporous molecular sieves could considerably change the reaction selectivity, at that methane being the main product of the methanol decomposition [31][32][33].…”