Insights into the contribution of oxygen vacancies on CO2 activation for dry reforming of methane over ceria-based solid solutions

•Catalytic performance of ceria-based materials is improved by doping trivalent ions.•Oxygen vacancies on the surface and in the bulk of solid solutions are quantitated.•Dynamic redox properties of catalysts are revealed via in-situ Raman characterization.•CO2 activation rate is identified as a descriptor for predicting catalytic stability.