Investigation on the mechanism of different valence states of copper-based catalysts to regulate catalyst ignition at low temperature

Abstract

Carbon monoxide (CO) emissions from vehicle exhaust pose a serious threat to both environmental ecology and human health. Copper-based oxides (CuO_x) have demonstrated remarkable potential during the cold-start phase of automobiles by catalytically oxidizing CO to CO₂. In this study, we focused on the low-temperature oxidation performance of copper-based catalysts and investigated the effects of calcination temperature and precipitant concentration on catalyst performance. At a Cu²⁺/Cu⁺ ratio of 1.44, a precipitant concentration of 0.3 mol/L, and a calcination temperature of 280 °C, the catalysts exhibited a cubic structure, with an enhancement in specific surface area, a larger pore volume, and an increase in the oxygen concentration of the lattice. The ignition temperature was optimized (T₅₀ = 130 °C), during which the catalyst primarilyd follows the Mars-Van Krevelen (MvK) mechanism and the Eley-Rideal (ER) mechanism occurs under oxygenation.