Effective Screening of Metal Dopants for In₂O₃ Catalyst to Tune Catalytic Performance of CO₂ Hydrogenation to Formic Acid

Abstract The metal doping is an effective strategy to adjust catalytic performance for indium oxide catalyst in CO 2 hydrogenation. In current work, a series dopant, Co, Fe, Ni, Pd, Pt, Rh, and Ru, are selected and examined in CO 2 hydrogenation to formic acid by DFT based microkinetic simulation. It is found that substitutional doping is local effect, which mainly promotes the reactivity of adjacent oxygen atoms. The calculations of both CO 2 adsorption and hydrogen molecule dissociation certify the positive effects induced by doping, and the adsorption energy of CO 2 has a linear relation with the transferred charges for all investigated catalysts which helps to explain the C─O bond activation mechanism. Two pathways, formate and carboxyl, are investigated under same footing. It is noted that doping significantly reduces the hydrogenation barriers on two pathways compared with undoped surfaces. Moreover, the calculated TOF of formic acid formation is greatly increased on doped surfaces and Pt, Pd, and Ru are identified as the most active dopants. In the end, it is concluded that reaction obeys carboxyl mechanism and a valid descriptor of trans‐HCOOH* and H* formation energy is proposed for the screening of effective dopants.