Synergistic CO2 hydrogenation with DBD plasma over a Ni-based catalyst prepared at low temperature

The integration of non-thermal plasma (NTP) with supported metal catalysts presents a promising strategy for the conversion of carbon dioxide under mild conditions. This study prepared catalysts at relatively low temperatures and employed dielectric barrier discharge (DBD) plasma to drive CO 2 hydrogenation under low-temperature reaction conditions. The optimization effect of CeO 2 loading on the performance of Ni/ZSM-5 catalysts was systematically investigated. The results indicate that the 15Ni-15Ce/ZSM-5 catalyst exhibits the most optimal performance. At a specific energy input (SEI) of 21.65 kJ/L, the CO 2 conversion rate reaches 88.6%, representing a more than fourfold improvement over the 15Ni/ZSM-5 catalyst. The selectivities for CH 4 , C 2 H 6 , and C 3 H 8 are 90.4%, 6.8%, and 2.0%, respectively. Characterization revealed that optimized low-temperature preparation conditions successfully generated highly dispersed metallic Ni 0 active sites. The introduction of CeO 2 further reduced Ni 0 particle size and created abundant oxygen vacancies. The 15Ni-15Ce/ZSM-5 catalyst enhances CO 2 adsorption and activation through oxygen vacancy-enhanced mechanisms, while NTP generates active H atoms from H 2 . Both processes synergistically drive efficient reaction progress. In situ DRIFTS analysis of surface species on 15Ni/ZSM-5 and 15Ni-15Ce/ZSM-5 catalysts under NTP conditions revealed the mechanism of NTP-catalyzed CO 2 methanation. Results indicate that hydrogenation on 15Ni/ZSM-5 primarily follows the CO pathway. After the introduction of CeO 2 , the reaction pathway changes, with the 15Ni-15Ce/ZSM-5 catalyst achieving highly selective hydrogenation mainly through the b-HCOO pathway.