Modulation of *CH_xO Adsorption to Facilitate Electrocatalytic Reduction of CO₂ to CH₄ over Cu-Based Catalysts

Abstract

Copper (Cu) can efficiently catalyze the electrochemical CO2 reduction reaction (CO2RR) to produce value-added fuels and chemicals, among which methane (CH4) has drawn attention due to its high mass energy density. However, the linear scaling relationship between the adsorption energies of *CO and *CH x O on Cu restricts the selectivity toward CH4. Alloying a secondary metal in Cu provides a new freedom to break the linear scaling relationship, thus regulating the product distribution. This paper describes a controllable electrodeposition approach to alloying Cu with oxophilic metal (M) to steer the reaction pathway toward CH4. The optimized La5Cu95 electrocatalyst exhibits a CH4 Faradaic efficiency of 64.5%, with the partial current density of 193.5 mA cm–2. The introduction of oxophilic La could lower the energy barrier for *CO hydrogenation to *CH x O by strengthening the M–O bond, which would also promote the breakage of the C–O bond in *CH3O for the formation of CH4. This work provides a new avenue for the design of Cu-based electrocatalysts to achieve high selectivity in CO2RR through the modulation of the adsorption behaviors of key intermediates.

A Surfactant-Free and General Strategy for the Synthesis of Bimetallic Core–Shell Nanocrystals on Reduced Graphene Oxide through Targeted Photodeposition

“…(c) CH 4 FEs at −1.18 V (vs RHE) on Pd, Pd 7 @Cu 1 , Pd 7 @Cu 2 , Pd 7 @Cu 3 , and Cu. (d) Comparison of this work with previous studies on the electrocatalytic CO 2 -to-CH 4 reaction in 1 M KOH by a flow cell device (refs − ). (e) Potential versus time of Pd 7 @Cu 2 at a constant current density of 100 mA·cm –2 and the corresponding CH 4 FE.…”

Atomically inner tandem catalysts for electrochemical reduction of carbon dioxide

“…2(a)) have been successfully demonstrated as CO 2 RR catalysts in the experiment, the Co–N–M dual sites may enable the adsorbed *CHO at the Co site to facilely migrate to the M site with or without PCET via a short-distance bridge bonding style or assisted bonding with bridge-N, thereby promoting the *OCH 2 formation through an inner tandem reaction. 34–36 Considering that the binding affinity of the O atom in *OCH 2 is closely related to the metal d electrons, we chose six 3d metals (Cr, Mn, Fe, Co, Ni, and Cu) with various d electron numbers to construct Co–N–M dual sites. According to the previous report on the experimental synthesis of Co–N–M dual sites, the geometric structures of Co–N–M catalysts were built as Co–N–M–N 6 moieties into the superlattice of graphene.…”

Electronic and geometric modulations of catalysts for electrochemical CO2 reduction reaction

“…117 Zhao et al reported that the oxophilic metal (La) was able to modulate the catalytic activity of Cu, improving the CH 4 selectivity (up to 64.5%), which was approximately 7.8 times higher than for Cu. 118 Infrared spectroscopy and DFT theoretical calculations showed that the presence of La would lead to stronger *CH x O adsorption and promote the cleavage of C–O for *CH 3 O, thus increasing the proportion of CH 4 in the products.…”