Influence of preparation method on catalytic performance of three-dimensionally ordered macroporous NiO–CuO for CO oxidation

A series of three-dimensionally ordered macroporous (3DOM) nickel−copper mixed oxides (with the NiO/CuO molar ratios of 3 : 3, 3 : 2, and 3 : 1) calcined at various temperatures (450, 550, and 650 ​°C) were prepared using the dual-templating (Pluronic P123 and polymethyl methacrylate (PMMA)) method in a mixed solution of ethylene glycol and methanol with different volumetric ratios (1 : 2, 1 : 1.5, and 1 : 1). The sample obtained after the use of P123 and PMMA exhibited a much higher catalytic activity for CO oxidation, over which a complete CO conversion was achieved at 138 ​°C, CO/O2 volumetric ratio ​= ​2 : 5, and space velocity ​= ​60,000 mL/(g h), and this catalyst possessed good stability in the presence of water vapor in the feed stream. The large surface area, high oxygen adspecies concentration, good low-temperature reducibility, and unique nanovoid 3DOM structure were accountable for the superior catalytic performance of the sample prepared by the dual P123- and PMMA-templating method.