Ceria-supported niobium oxide catalyst for low-temperature oxidation of 1,3-butadiene

Low-temperature oxidation represents an economically efficient way to convert spinoff hydrocarbons such as butadiene into nontoxic species. This study investigates the catalytic oxidation of 1,3-butadiene over ceria-supported niobium oxide, exploring the synthesis routes and catalytic performances. Experimental characterization techniques, including X-ray spectroscopy and diffractometry, microscopy, and other micro-characterisations, elucidate the structure of the catalysts as corroborated by the density functional theory (DFT) method. DFT calculations constructed the underlying oxidative reaction mechanisms that ensue through accessible activation energies in steps that feature subsequent C[sbnd]C bond fissions, H transfer reactions, CO desorption, and formation of CO₂ molecules. The results show that, the niobium oxide assumes mainly the form of Nb₂O₅ on ceria supports, and plays a significant role in switching the physicochemical nature of ceria and the resulting catalysts. Despite a relatively lower surface area, the NbO_x/CeO₂ catalysts exhibit superior performances in the conversion of butadiene compared to pure ceria. The catalyst prepared with 10 wt.% of Nb has the best catalytic performance with 82% conversion of butadiene, highest reaction rate, and selectivity towards CO₂ of 95% at the temperature range of 300 – 400 °C and a gas hourly space velocity (GHSV) of 34,600 h⁻¹. Obtained results entail practical environmental implications in the catalytic destruction of stable hydrocarbon species.