Zirconium oxide@N-doped porous carbons with oxygen vacancies, derived from zirconium chloride embedded metal-azolate framework-6: A new oxidative desulfurization catalyst

ZrO₂ supported on porous N-doped carbon (ZrO₂@CN), with oxygen vacancy was firstly prepared via carbonization of a composite of the metal-azolate framework (MAF-6) and zirconium chloride (ZrCl₄), termed ZrCl₄(x)@MAF-6. The derived ZrO₂@CN was investigated as a catalyst to remove thiophenics from fuels via an oxidation reaction with H₂O₂ oxidant. A selected catalyst, ZrO₂(2)@CN, showed a noticeable turnover frequency (19 h⁻¹) and activation energy (32.0 kJ mole^-1) in oxidative desulfurization (ODS) with good recyclability. The high activity of ZrO₂@CN in ODS is due to •OH species, which might be effectively produced via a synergy between Zr atom with O vacancy and N of carbon support for H₂O₂ activation. Moreover, our calculation also supported the beneficial role of an oxygen vacancy of ZrO₂ in the H₂O₂ activation. Therefore, ZrO₂, especially ZrO₂@CN with oxygen vacancy, could be first suggested as an ODS catalyst although ZrO₂ was earlier used as a support of catalysts.