Low-temperature CO oxidation over Co3O4-based catalysts: Significant promoting effect of Bi2O3 on Co3O4 catalyst

Integrated Cobalt Oxide Based Nanoarray Catalysts with Hierarchical Architectures: In Situ Raman Spectroscopy Investigation on the Carbon Monoxide Reaction Mechanism

“…[10,15,50,51] In contrast, some researchers revealed that the CO oxidation reactionm echanism can follow the LH mechanism, which includes the main four steps in CO oxidation:1 )COa dsorption on the cationic metal sites, 2) the formation of active oxygen that resultsf rom O 2 molecules adsorbed on oxygen vacancies, 3) the reaction of CO with active oxygen, and 4) CO 2 desorption from the catalyst surface. According to previous studies, [9,10,15] the choice of as uitable doping cation can create structurald efects and residual stress as well as oxygen vacancies. These previous studies suggested that there are no clear reaction mechanisms on certain catalysts for CO oxidation and that tuningt he surface structurald efects (CO adsorption and the formation of active oxygen) of am aterial should be an efficient method to design new catalysts.…”

“…[1,2] Nevertheless, there are still some inevitable disadvantages that need to be overcome,s uch as the requirement of ah igh temperature (300-400 8C) to catalyze the exhaust gas at nearly 100 %c onversion, ai nhomogeneous distribution of active species, and an increasingly high cost. [7,[9][10][11][12][13][14] For instance, Xie et al [13] reported that Co 3 O 4 nanorods with predominantly exposed (110)p lanes calcined at 450 8Cc ould catalyze CO oxidation at temperatures as low as À77 8Ca taspace velocity (SV) of 15 000 mL h À1 g cat À1 . [3][4][5][6][7][8] These studies on the design and synthesis of catalysts are divided into two types:p owder catalysts and monolithic catalysts.…”

“…Lou et al [9,10] reported that Bi 2 O 3 -Co 3 O 4 and In 2 O 3 -Co 3 O 4 promote the catalytic performancef or CO oxidation significantly and showed ac atalytic activityf or CO oxidation at as low as À89 and À105 8C, respectively.I na ddition, commercial powdered catalysts such as Pt-Pd-Rh coated on am onolithic ce-Herein, af acile strategy for the in situ growth of aC o 3 O 4 -based precursor with unique hierarchicala rchitectures oriented diagonal or perpendicular to Ni surfaces is reported. This strategy to prepare grafted ZIF-67@Co 3 O 4 and MOF-199@Co 3 O 4 precursor structures is based on as imple hydrothermals ynthesis methodt oo btain the Co 3 O 4 precursor and the subsequent in situ growth of ZIF-67 and MOF-199, respectively.T he morphologies of the Co 3 O 4 products can be tailoredb yc ontrolling the solvent polarity and concentration of precipitants.…”

Enhancing Catalytic CO Oxidation over Co3O4 Nanowires by Substituting Co2+ with Cu2+

“…In this regard, Cu 2+ is an ideal candidate for substituting Co 2+ in the Co 3 O 4 lattice because the Cu 2+ cation not only is active for CO oxidation, 1,15,16 but also has an ionic radius that is similar to that of the Co 2+ cation (Figure 1). In addition, replacing Co 2+ with Cu 2+ could also modify the intrinsic activity of Co 3+ by changing the bonding environment surrounding Co. 8,[17][18][19][20][21] In this study, we show that replacing Co 2+ with Cu 2+ cations in polycrystalline Co 3 O 4 nanowires greatly enhances their catalytic activity for CO oxidation. The Co 2+ cation…”

Hydrothermal Synthesis of a Novel Double‐Sided Nanobrush Co3O4 Catalyst and Its Catalytic Performance for Benzene Oxidation

“…As is known, lattice defects can promote the formation of oxygen vacancies, further benefitting the activation of oxygen species. [37][38][39] The surface elemental compositions and chemical states of the synthesized Co 3 O 4 catalysts were analyzed by XPS. Figure 4 shows the Co 2p and O 1s XPS spectra of the Co 3 O 4 catalysts, and the resulting ratios of Co 3 + /Co 2 + and O latt /O ads on the surface, determined by integrating the fit curve peaks, are illustrated in Table 1.…”