Influence of Co addition on Ni-Co mixed oxide catalysts toward the deep oxidation of low-rank unsaturated hydrocarbons

Investigation of the effect of thermal annealing of Ni-cobaltite nanoparticles on their structure, electronic properties and performance as catalysts for the total oxidation of dimethyl ether

“…6a display significant peaks centered at binding energies (BE) of ∼780.3 and ∼796.2 eV, which are assigned to the Co 2p 3/2 and Co 2p 1/2 core shells, respectively, in agreement with previously reported data. 13,49 The Gaussian fitting analysis displays two signals that could be segregated into two spin–orbit doublets, implying the presence of both Co 2+ and Co 3+ in the matrix of the entire NiCo 2 O 4 . The signals located at ∼780.96 and ∼797.24 eV are associated with Co 3+ whereas the peaks at ∼779.43 and ∼793.80 eV are assigned to Co 2+ species in NiCo 2 O 4 .…”

“…Recently, we reported the deep oxidation of low-rank unsaturated hydrocarbons including acetylene and propene over rock-salt NiCoO 2 and spinel NiCo 2 O 4 thin films, with outstanding performance, stability, durability, and reusability for the latter. 13 Mihai et al 44 likewise later described the unravelling effects of the electrical conductivity on the total oxidation of methane over coprecipitated MCo 2 O 4 (M = Ni, Cu, Mn) nanoparticle (NP) catalysts with NiCo 2 O 4 operating via a suprafacial process. Having demonstrated the catalytic applicability of NiCo 2 O 4 , it is important to investigate some aspects that can influence the performance.…”

“…Two types of catalyst have been developed for the lowtemperature oxidation, namely supported precious metals (Ag, Au, Pt and Pd) [6][7][8][9] and mixed metal oxides. [10][11][12][13][14] Several studies on the total oxidation of DME over Au, Pt, Pd, Rh, and Ru catalysts supported on different oxides including Al 2 O 3 , ZrO 2 , TiO 2 and CeO 2 have been performed 6,[15][16][17][18][19] and the results revealed that Ru and Pt catalysts supported on Al 2 O 4 exhibit total oxidation of DME to CO 2 and H 2 O within the temperature range from 400 to 600 °C, which is not satisfactory for low-temperature activity. In addition, the disadvantages of noble metals are their higher cost, poor availability, poisoning tendency and unsuitable and expensive investment for industrial applications.…”

“…20,21 Therefore, TMOs have received much attention in the total oxidation of volatile organic compounds (VOCs) and exhaust gases. [9][10][11][12][13][14]22,23 Of the single metal oxides, Co 3 O 4 has gained increasing attention as an effective, inexpensive and active catalyst with comparable performance to supported precious metal catalysts. 24,25 However, it is well-established that the incorporation of a second metal in the matrix of normal spinel Co 3 O 4 induces metal-metal or metal-oxygen-metal interactions with notable effects on the metallic radii.…”

“…As far as doping is concerned, pertinent investigations into the combination of Co and Ni to achieve highly dispersed catalytic active NiCo 2 O 4 NPs have been reported recently. 13,44 However, systematic studies on the effect of NiCo 2 O 4 thermal treatment on the physicochemical properties and the catalytic activity have not yet been reported. Thermal annealing is commonly used to remove surface contaminants and favour the elementals redistribution in the metal oxide matrix.…”