Low-temperature deep oxidation of N,N-dimethylformamide (DMF) over CeCu binary oxides

Abstract

A binary oxide of ceria–copper was fabricated via the sol–gel technique for converting N,N-dimethylformamide (DMF) to harmless gases. The structure-chemical morphology, redox properties and bandgap energies of the synthesized oxides were comprehensively analyzed using XRD, BET, TEM, HRTEM, EDS-HAADF, XPS, TPR/TPO and UV-vis. XRD and BET spectra reveal that the increment in Cu content reduces the crystallite size and increases the pore volume of the nanopowder catalysts. The difference in O_Lat, Cu²⁺/Cu⁺, and Ce³⁺/Ce⁴⁺ at the surface with Cu loading significantly affects the catalytic activity. The TPR/TPO results indicate that doping CeO_x with Cu improved the redox properties at lower temperatures. The incorporation of Cu shifts the light-off curves towards low temperatures. According to the XPS results, the increased catalytic performance and stability are ascribed to the oxygen vacancies' abundance in the doped oxides. Ce₁₀Cu₉₀ binary oxide unveiled the best DMF conversion of ∼98% because of its low E_a and E_g, as well as the largest amount of Cu²⁺, and Ce³⁺ species. A proposed mechanism was developed to explain the decomposition of DMF to produce NO₂ and CO₂. These findings suggest that Ce₁₀Cu₉₀ is an efficient and stable catalyst for industrial applications.