Highly Enhanced Chloride Adsorption Mediates Efficient Neutral CO₂ Electroreduction over a Dual-Phase Copper Catalyst

Abstract

Electrocatalytic carbon dioxide reduction (CO2R) in neutral electrolytes can mitigate the energy and carbon losses caused by carbonate formation but often experiences unsatisfied multicarbon selectivity and reaction rates because of the kinetic limitation to the critical carbon monoxide (CO)–CO coupling step. Here, we describe that a dual-phase copper-based catalyst with abundant Cu­(I) sites at the amorphous–nanocrystalline interfaces, which is electrochemically robust in reducing environments, can enhance chloride-specific adsorption and consequently mediate local *CO coverage for improved CO–CO coupling kinetics. Using this catalyst design strategy, we demonstrate efficient multicarbon production from CO2R in a neutral potassium chloride electrolyte (pH ∼6.6) with a high Faradaic efficiency of 81% and a partial current density of 322 milliamperes per square centimeter. This catalyst is stable after 45 h of operation at current densities relevant to commercial CO2 electrolysis (300 mA per square centimeter).

Alkaline Ionic Liquid Microphase Promotes Deep Reduction of CO2 on Copper

“…The catalytic stability of Cu@AIL was evaluated via constant current electrolysis at 0.6 A cm –2 for 18 h. There is a slight increase in the potential, and the C 2+ product FE remains almost constant during electrolysis (Figure S17). It might be caused by the reaction of CO 2 with OH – to form carbonate, which could block the gas diffusion electrode and lead to an increase in the resistance of the device . The Cu@AIL after the CO 2 RR was characterized by XRD and SEM.…”

“…Electrocatalytic CO 2 reduction reaction (CO 2 RR) powered by renewable energy sources is a promising route to both reduce greenhouse gas concentration in air and achieve renewable energy storage. − Among the various reduction products obtained from electrocatalytic CO 2 RR, multicarbon (C 2+ ) products are the most popular because of their high energy densities and industrial values. − Up to now, the electrochemical conversion of CO 2 to C 2+ products still presents many challenges, such as higher overpotential and lower product selectivity (especially at ampere-level current densities) than C 1 products. − The limitations are primarily restricted by the high energy barriers of CO 2 activation and CO dimerization. − Therefore, it is crucial to develop efficient electrocatalysts for facilitating CO 2 activation and promoting C–C coupling reaction for C 2+ products.…”

Linking Electric Double Layer Formation to Electrocatalytic Activity

“…As a specific example, classical models of electric double layer formation prohibit co-ions from being in the bound layer, as such an outcome would incur both electrostatic and entropic penalties. Yet, co-ion effects are common in electrochemistry and electrocatalysis. − …”

Conducting 2D Nanosheets: Photo Driven Crystallinity in Self-Assembled Cu (II) Metalated Porphyrin-Bispyridylquinoxaline

“…As known, transition metals possess excellent binding energy, electron affinity, ionization, and chemical hardness . Because copper has a higher binding energy with nitrogen atom in porphyrin than zinc metal, it assists anion binding formation in chloroform under UV light with a wavelength of 365 nm, while zinc based P-DPQ leads to demetalation. − These mechanisms influence the ground and excited state electronic properties of P-DPQs which facilitate an improvement of the bulk conductivity. In addition, light stimulated molecules show a substantial impact on molecular packing to direct the 0D and 2D self-assembled structures with amorphous and crystalline nature (Figure ).…”