Multi-metal composite layered materials derived from ZIF-67 for enhanced toluene oxidation

Amidst the increasing concerns regarding the emission of volatile organic compounds (VOCs), the pressing task at hand is the development of effective and environmentally benign technologies for catalytic VOC reduction. In the context of this research endeavor, the distinct attributes of zeolite imidazoline framework (ZIF-67), known for its high yield, absence of deleterious by-products, and rapid synthesis, are harnessed. In pursuit of this goal, a series of ZIF-67-derived layered double oxides (LDO) multimetallic composite shell materials for toluene combustion were successfully synthesized: CoNi-LDO and CoNiM-LDO (M = Ce, Cu, Mn and Fe).The experimental results show that due to the uniform dispersion of Co, Ni, and Cu atoms within the CoNiCu-LDO catalyst, the prevalence of oxygen vacancies, a significant specific surface area, and robust interactions among these constituents, a synergistic formation involving Ov - Cu2+ - O2 - Co3+ - O2 - Ni3+ emerges, the CoNiCu-LDO exhibits an excellent catalytic efficiency. Furthermore, through Density Functional Theory (DFT), the adsorption energies and the projected density of states (PDOS) for toluene, O2, H2O, and SO2 on the catalysts have been meticulously computed. Ultimately, the intricate mechanism underpinning the catalytic oxidation of toluene on CoNiCu-LDO has been unveiled through in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS).