Engineering lattice oxygen mobility and optimizing reaction pathway via tuning Cu-Co interactions for efficient elimination of volatile organic compounds: A metal–organic framework template approach

Abstract

Incorporating a secondary metal into individual cobalt oxides has been viewed as an efficacious approach in creating intermetallic interactions. Nonetheless, the processes involved in the construction of intermetallic interactions, as well as the underlying mechanisms that contribute to catalytic activity, remain largely elusive in current scientific understanding. In this work, a range of Cu-Co bimetallic oxides were synthesized through various preparation methods, employing MOFs as templates. Notably, the hydrothermally-synthesized Cu/Co-HT catalyst exhibited impressive catalytic qualities for toluene combustion, with T50 = 229 °C and T90 = 239 °C, alongside exceptional stability and moisture resistance (under 10 vol. % of water) for at least 100 h. The optimal catalyst Cu/Co-HT is attributed to the stronger Cu-Co interaction, which leading to larger specific surface area and weaker Co-O bond strength. And it also affects the chemical properties, such as get more Co3+ and lattice oxygen species by a redox (Co2++Cu2+→Co3++Cu+), better electron transfer performance and low-temperature reducibility. In addition, the reaction mechanism of toluene over the surface of Cu/Co-HT was also revealed by in-situ DRIFTS. It was observed that the bimetallic catalyst, characterized by robust Cu-Co interactions, optimized the reaction pathway for toluene oxidation compared to pure Co3O4. This facilitation led to the direct conversion of benzyl alcohol into benzoate and carboxylate, thereby bypassing the intermediate step involving benzaldehyde, which enhancing the reaction speed, yielding a long-term stable and efficient operational performance. This study reveals that optimize the physicochemical properties of catalytic by enhancing bimetallic interactions is an effective strategy for improving catalytic behavior.