Effect of oxygen vacancy of lignite-char-supported Co catalysts doped with In on efficient dry reforming of methane

[Display omitted] •In2O3 doping boosts oxygen vacancies, enhancing catalyst performance.•2 wt% In doped Co/C catalyst shows improved initial activity and stability.•The shorter induction time is due to the promotion of oxygen vacancies.•In2O3 doping accelerates the rate of carbon removal.•Increased oxygen vacancies inhibit deep methane dissociation for long-term reforming. In this study, a series of catalysts rich in oxygen vacancies were prepared through the introduction of indium (In) for application in the dry reforming of methane. Among these catalysts, one doped with 2 wt% In, named as Co-2In/C, showcases a higher surface area (417 m2/g) and smaller particle size (4.21 nm). The stability assessment for Co-2In/C catalysts conducted under conditions of 800 °C, 0.5 MPa and a flow rate of 30,000 mL·h−1·g-1cat over 100 h resulted in CH4 and CO2 conversions of 73 % and 83 %, respectively, and a ratio of H2/CO is 0.65 without evident deactivation. The generation of more oxygen vacancies balances the redox capability of the catalyst and prevents excessive metal agglomeration. Moreover, an increase in oxygen vacancy concentration accelerates carbon elimination and extends the catalyst life.