Synergetic effect of non-thermal plasma and supported cobalt catalyst in plasma-enhanced CO2 hydrogenation

Non-thermal plasma can provide an alternative to CO2 utilization under mild conditions. Understanding the effect of plasma on catalysis is highly desired. Herein, a comparative study was performed on CO2 hydrogenation under thermal-catalytic and plasma-catalytic conditions using an alumina-supported cobalt catalyst. Significant plasma-catalyst synergy was attained at the low-temperature range between 423 K and 498 K where the CO2 conversion increased up to approximately 3.6 times of the sum of that using plasma or catalyst individually. The plasma-catalytic reaction showed a significantly lower activation energy (-40 kJ/mol), which is only half of that in the thermal catalytic reaction (-80 kJ/mol). Kinetic analysis and DRIFTS results indicate that CO2 activation is promoted by plasma with the assistance of active H species from gas phase. Furthermore, the total H-2 adsorption capacity and the coverage of irreversible adsorbed H species on the metal surface were decreased under plasma. The promotion effect is very likely due to a new reaction pathway introduced by plasma on the 15Co/Al2O3 catalyst under the conditions studied. No obvious difference in the structure and morphology changes was observed between the spent catalysts after thermal and plasma reactions.

Automated summary

This study compared CO2 hydrogenation under thermal-catalytic and plasma-catalytic conditions. The results showed significant synergy between plasma and catalyst at low temperatures, leading to increased CO2 conversion. The plasma-catalytic reaction had lower activation energy and promoted CO2 activation.