Reaction Characteristics of Precious-Metal-Free Ternary Mn–Cu–M (M = Ce, Co, Cr, and Fe) Oxide Catalysts for Low-Temperature CO Oxidation

Abstract

In this paper, we prepared binary Mn−Cu and M (M = Ce, Co, Cr, and Fe)-added ternary Mn−Cu−M oxide catalysts using the redox precipitation method, and their catalytic performances in low-temperature CO oxidation were investigated. The prepared catalysts were characterized using XRD, SEM, N 2 adsorption/desorption isotherms, XPS, and H 2 -TPR techniques. It was observed that the CO oxidation performance at low temperature improved significantly when Cu and other dopants were added. The optimum molar ratio of Mn to Cu in a binary oxide catalyst was 1.0/0.1. The Mn−Cu−Co oxide catalyst had the highest activity, which was converted 90% of the CO at the relatively low temperature of 75 °C, among the prepared catalysts. It was concluded that the improvement of oxygen mobility and textural properties for Mn−Cu−Co catalyst are more favorably influenced on the enhanced catalytic activity.

Mesoporous Co‐Al oxide nanosheets as highly efficient catalysts for CO oxidation

“…The oxidation of carbon monoxide (CO) over heterogeneous catalysts is of great importance due not only to the practical applications in automotive gas treatment, indoor air cleaning, and CO removal from H 2 feed gas for fuel cells, but also to its use as a model reaction in laboratory research . Up to now, many highly efficient catalysts for CO oxidation, mainly including supported noble metals (such as Au and Pt) and metal‐oxides (such as Co 3 O 4 and MnO 2 ) have been successfully developed . For example, TiO 2 ‐supported Au catalyst is very active for CO oxidation at the temperature of −70°C .…”

“…Metal oxides are less expensive compared with supported noble metals, which enhances their potential for practical applications. It has been reported that MnO 2 , CuO, CeO 2 , and Co 3 O 4 oxides exhibit good performances in low‐temperature CO oxidation and catalytic oxidation reactions . Among these materials, cobalt oxide catalysts show excellent performance, and the catalytic activities can be improved through various strategies.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Up to now, many highly efficient catalysts for CO oxidation, mainly including supported noble metals (such as Au and Pt) 8,9,11,12,[19][20][21][22][23][24][25] and metal-oxides (such as Co 3 O 4 and MnO 2 ) have been successfully developed. 7,[13][14][15][16][17][18][26][27][28][29][30][31][32][33] For example, TiO 2 -supported Au catalyst is very active for CO oxidation at the temperature of −70 C. 19-21 SiO 2 -supported Pt-Fe catalysts give almost 100% CO conversion and 100% CO selectivity at room temperature. 8 Metal oxides are less expensive compared with supported noble metals, which enhances their potential for practical applications.…”

“…performances in low-temperature CO oxidation and catalytic oxidation reactions. 7,13,[26][27][28][29][30][31][32][33][34][35] Among these materials, cobalt oxide catalysts show excellent performance, and the catalytic activities can be improved through various strategies. For example, Co 3 O 4 nanorods with higher exposure of (110) planes exhibit full conversion of CO at −77 C. 7 35 After the introduction of mesoporosity, the mesoporous Co 3 O 4 catalyst with enhanced surface area becomes more active than the bulk one, giving T 50 (temperature for 50% CO conversion) value of 4 C. 34 Upon doping In 3+ species into Co 3 O 4 , the catalyst can completely convert CO to CO 2 at temperatures as low as −105 C. 26 Clearly, the strategies for exposure of catalytically active sites such as inducing of mesoporosity is highly efficient.…”

The choice of precursors in the synthesizing of CuMnOx catalysts for maximizing CO oxidation

“…According to Hutching et al, the performance of CuMnOx catalysts very much depends upon the calcination conditions of the precursors and the subsequent pretreatment of the catalysts [26]. The high-temperature calcination causes sintering of the active crystallites with a consequent loss of surface area and subsequently adversely affects on the performance of the catalyst [27].…”