Computational Design of Copper doped Indium for electrocatalytic Reduction of CO₂ to Formic Acid

Abstract

Electrochemical reduction of CO 2 to formic acid is crucial to achieve a low carbon cycle and mitigate the energy crisis. Density functional calculation is deemed to be an important method for designing highly efficient catalysts for CO 2 electrochemical reduction (CO 2 ER). CuÀ In alloy is mostly reported to show an increasing selectivity of reducing CO 2 to CO, however the performance of CO 2 ER over In with tiny amount of Cu doping and the influence of trace Cu to the reaction are rarely researched. Here, The CO 2 ER mechanism over In and trace Cu doped In (denoted as CuÀ In) catalysts are theoretically investigated. Additionally, the relative reduction pathways and Gibbs free energies of the key intermediates (*COOH and HCOO*) are calculated, which show that CuÀ In can produce formic acid more efficiently since CuÀ In surface prefers to adsorb HCOO* to form formic acid and decrease the production of CO. Additionally, the theoretical calculation is verified by experimental results. The designed CuÀ In catalyst (containing 1.55 wt % Cu) shows a high Faraday efficiency of 70 % for formate in CO 2 saturated 0.5 M NaHCO 3 electrolyte, which is much better than pure In (56 %).

Asymmetric Oxo‐Bridged ZnPb Bimetallic Electrocatalysis Boosting CO2‐to‐HCOOH Reduction

“…Among the expected ECR products, formate (a liquid fuel or fuel additive; HCOOH/HCOO ‐ ) is highly desirable because it has the highest energy values (current market price per energy unit) [ 6 ] having advantages in terms of handling, transportation, and storage, in addition, being non‐flammable and nontoxic supply for the electric energy generation. Metal‐based ECR electrocatalysts including In, [ 7 , 8 , 9 , 10 ] Sn, [ 11 , 12 , 13 , 14 ] Bi, [ 15 , 16 , 17 ] and Pb [ 13 , 18 , 19 ] are distinctive in their ability to selectively reduce CO 2 into formate reaching Faradic efficiency (FE HCOOH ) of >90%. [ 20 ] It is worth noting that for Pb‐based electrocatalysts, the CO 2 ‐to‐HCOOH activity performance still suffers from the relatively low partial current densities; j formate /j HCOO ‐ .…”

In Situ Carbon Encapsulation Confined Nickel-Doped Indium Oxide Nanocrystals for Boosting CO2 Electroreduction to the Industrial Level

“…To further shed light on the origin of the enhanced activity of CO 2 RR, we used the CP2K package for the DFT calculations (Figure S19). The In-based catalysts produce HCOOH or CO through two PCET steps, in which HCOOH is mainly generated through the OCHO* intermediate (protonation of carbon atom in CO 2 ) route, and CO is generated through the COOH* intermediate (protonation of the oxygen atom in CO 2 ) route . As illustrated in Figures a and S20, Ni-In 2 O 3 @C NFs show a lower Δ G (the difference of Gibbs free energy) for the formation of OCHO* (0.26 eV) than that of COOH* (0.97 eV), revealing that the Ni-In 2 O 3 @C NFs is more inclined to produce formate rather than CO. A lowest Δ G of OCHO* formation is observed for Ni-In 2 O 3 @C NFs (Figure a), suggesting that Ni-In 2 O 3 @C NFs is thermodynamically more favorable for the electrocatalytic reduction of CO 2 to formate, and in particular, the energy required for OCHO* formation was significantly reduced by nickel doping, which agrees well with the intrinsic activity obtained from the experimental results (Figure a).…”

Regulation Strategy of Nanostructured Engineering on Indium‐Based Materials for Electrocatalytic Conversion of CO2

“…first carried out a theoretical calculation of the CO 2 RR reaction mechanism for trace Cu‐doped In catalysts, and then prepared Cu‐In catalysts with a Cu content of 1.55 wt% to support the demonstration. [ 258 ] Cu‐In catalysts exhibit excellent performance with a maximum formate selectivity of 70%, which is higher than that of pure In catalysts with FE of 56%. The comparison of theoretical calculations with the free energy change shows that the performance of the Cu‐In catalyst does not depend on the adsorption of *COOH, but on the selective adsorption of HCOO*.…”