We developed a microkinetic model to reveal the effects of plasma-generated radicals, intermediates, and vibrationally excited species on the catalytic hydrogenation of CO 2 to CH 3 OH on a Cu(111) surface. As a benchmark, we first present the mechanisms of thermal catalytic CH 3 OH formation. Our model predicts that the reverse water-gas shift reaction followed by CO hydrogenation, together with the formate path, mainly contribute to CH 3 OH formation in thermal catalysis. Adding plasma-generated radicals and intermediates results in a higher CH 3 OH turnover frequency (TOF) by six to seven orders of magnitude, showing the potential of plasma-catalytic CO 2 hydrogenation into CH 3 OH, in accordance with the literature. In addition, CO 2 vibrational excitation further increases the CH 3 OH TOF, but the effect is limited due to relatively low vibrational temperatures under typical plasma catalysis conditions. The predicted increase in CH 3 OH formation by plasma catalysis is mainly attributed to the increased importance of the formate path. In addition, the conversion of plasma-generated CO to HCO* and subsequent HCOO* or H 2 CO* formation contribute to CH 3 OH formation. Both pathways bypass the HCOO* formation from CO 2 , which is the main bottleneck in the process. Hence, our model points toward the important role of CO, but also O, OH, and H radicals, as they influence the reactions that consume CO 2 and CO. In addition, our model reveals that the H pressure should not be smaller than ca. half of the O pressure in the plasma as this would cause O* poisoning, which would result in very small product TOFs. Thus, plasma conditions should be targeted with a high CO and H content as this is favorable for CH 3 OH formation, while the O content should be minimized.

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