Transition Metal Ion Doping on ZIF‐8 Enhances the Electrochemical CO₂ Reduction Reaction

Abstract

The electrochemical reduction of CO2 to diverse value‐added chemicals is a unique, environmentally friendly approach for curbing greenhouse gas emissions while addressing sluggish catalytic activity and low Faradaic efficiency (FE) of electrocatalysts. Here, zeolite‐imidazolate‐frameworks‐8 (ZIF‐8) containing various transition metal ions—Ni, Fe, and Cu—at varying concentrations upon doping are fabricated for the electrocatalytic CO2 reduction reaction (CO2RR) to carbon monoxide (CO) without further processing. Atom coordination environments and theoretical electrocatalytic performance are scrutinized via X‐ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations. Upon optimized Cu doping on ZIF‐8, Cu0.5Zn0.5/ZIF‐8 achieves a high partial current density of 11.57 mA cm–2 and maximum FE for CO of 88.5% at –1.0 V (versus RHE) with a stable catalytic activity over 6 h. Furthermore, the electron‐rich sp2 C atom facilitates COOH* promotion after Cu doping of ZIF‐8, leading to a local effect between the zinc–nitrogen (Zn–N4) and copper–nitrogen (Cu–N4) moieties. Additionally, the advanced CO2RR pathway is illustrated from various perspectives, including the pre‐H‐covered state under the CO2RR. The findings expand the pool of efficient metal–organic framework (MOF)‐based CO2RR catalysts, deeming them viable alternatives to conventional catalysts.

Electrochromic electrically conductive Cu3(HHTP)2 films with adaptation to diverse and low-concentration water

“…The reasons for the slight differences in electrochemical behaviour are as follows: (1) steric resistance with the pathway induced by the radii of solvated species and (2) electrostatic interaction between the crystal framework and the ions induced by both the ion size and charges of the ions. 4,35 In contrast, films had slower colouration/bleaching time and less change in optical contrast in aqueous LiCl solution (Fig. S7, ESI†) and LiClO 4 /propylene carbonate solution (Fig.…”

MOF-derived transition metal-based catalysts for the electrochemical reduction of CO2to CO: a mini review

“…5a). 102 Therein, Cu 0.5 Zn 0.5 /ZIF-8 was found to have the largest partial current density of 11.57 mA cm À2 and the highest FE CO of 88.5% at À1 V vs. RHE. Cu doping was revealed to change the electronic properties of sp 2 carbon atoms and promoted the COOH* intermediate formation.…”

Prospects and Promises in Two-Electron Water Oxidation for Hydrogen Peroxide Generation

“…Doping engineering is a critical strategy in the enhancement of the activity of pristine catalysts, which involves the introduction of impurity atoms into a material to modify its properties. , Within the context of the competitive dynamics of 4e – and 2e – WOR, elemental doping possesses the potential to modify the electronic structure, which effectively improves the selectivity of H 2 O 2 production . Doping can also contribute to the stability of the catalysts under harsh operating conditions.…”