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

Abstract

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.