CO2-intensified dry reforming of methane over oxygen-defective Ni-CeO2 catalysts: Synergistic coupling with reverse water-gas shift reaction

• Ni-CeO 2 catalysts were synthesized using a cellulose-assisted combustion method. • 15 wt% Ni-CeO 2 catalyst showed optimal Ni dispersion and oxygen storage capacity. • SCDR combines DRM and RWGS to enhance CH 4 conversion and CO 2 utilization. • In DRM, catalytic activity is primarily governed by the number of Ni active sites. • In SCDR, the OSC facilitates CO 2 activation and improves catalytic performance. This study investigates the performance of Ni-CeO 2 catalysts synthesized via a cellulose-assisted combustion method (CACS) for the synergistic coupling of dry reforming of methane (DRM) and the reverse water–gas shift reaction (RWGS), referred to as SCDR. Among the catalysts with varying Ni loadings, the 15 wt% Ni-CeO 2 catalyst exhibited an optimal balance of Ni dispersion and oxygen vacancy formation, achieving superior CH 4 and CO 2 conversions. In DRM reaction, catalytic activity was primarily determined by the number of Ni active sites, with higher Ni dispersion enhancing CH 4 conversion. In contrast, under SCDR conditions, catalytic performance was significantly influenced by the oxygen storage capacity (OSC), which facilitated CO 2 activation and intermediate formation. The well-dispersed Ni and strong metal-support interaction at the Ni-O-Ce interface further promoted CO 2 activation, improving sintering resistance and enabling the formation of key intermediates such as bidentate carbonates and formates. These intermediates were essential for sustaining reaction turnover, with the Ni-O-Ce interface contributing to the rapid regeneration of active sites and maintaining catalytic activity under CO 2 -rich conditions. Additionally, the high CO 2 partial pressure in SCDR suppressed carbon deposition, enhancing stability and reaction rates compared to DRM.