Theoretical Insights into Enhancing Catalytic Performance of Al-Cu Alloy for CO2 Electroreduction toward Ethene Production

The understanding of the reaction mechanism of CO2 electroreduction (CO2RR) is essential for the precise design of catalysts for specific products with high selectivity. In this work, combined with the computational hydrogen electrode model and kinetic energy barrier calculations, CO2RR pathways on Cu(100) and Al1Cu3(100) are intensively investigated. The free energy barrier of the rate-determining step of ethylene formation is reduced from 1.08 eV for *CCOH formation on Cu(100) to 0.51 eV for *CH2OCHOH formation on Al1Cu3(100) and enhances the catalytic activity. The reaction free energy of *CO-*CO coupling is remarkably reduced from 0.86 eV on Cu(100) to -0.43 eV on Al1Cu3(100) and the coupling barrier is reduced from 0.97 to 0.37 eV, suppressing the production of gas phase CO and enhancing the production of C2 products. Furthermore, the selectivity toward C-O breaking of *CH2CHOH on Cu(100) and *CH2CH2OH on Al1Cu3(100) ensures high selectivity toward ethene rather than ethanol.

Research Progress of Copper-Based Bimetallic Electrocatalytic Reduction of CO2

Fossil fuels are still the main source of energy in today’s society, so emissions of CO2 are inevitable, but when the CO2 level in the atmosphere is too high, many environmental problems will arise, such as the greenhouse effect, among others. Electrocatalytic reduction of CO2 is one of the most important methods that one can use to reduce the amount of CO2 in the atmosphere. This paper reviews bimetallic catalysts prepared on the basis of copper materials, such as Ag, Au, Zn and Ni. The effects of different ratios of metal atoms in the bimetallic catalysts on the selectivity of CO2RR were investigated and the effects of bimetallic catalysts on the CO2RR of different ligands were also analysed. Finally, this paper points out that the real reaction of CO2RR still needs to be studied and analysed, and the effect of the specific reaction environment on selectivity has not been thoroughly studied. This article also describes some of the problems encountered so far.

Boosting CO2 electroreduction on a Zn electrode via concurrent surface reconstruction and interfacial surfactant modification

Herein, we report an effective strategy for improving the electrocatalytic CO₂ reduction reaction (CO₂RR) performance of a Zn foil electrode via concurrent surface reconstruction and interfacial surfactant modification. The oxide-derived and CTAB-modified Zn electrode (OD-Zn-CTAB) prepared by electrochemically reducing the air-annealed Zn foil electrode in the presence of CTAB exhibits high electrocatalytic activity and selectivity for CO production with a CO partial current density (j_CO) of 8.2 mA cm^-2 and a CO faradaic efficiency (FE_CO) of 90% at -1.0 V vs. the reversible hydrogen electrode (RHE), greatly outperforming the pristine Zn foil (FE_CO = 32.0%; j_CO = 0.5 mA cm^-2) and OD-Zn (FE_CO = 77.6%; j_CO = 5.0 mA cm^-2) obtained by electroreduction of annealed Zn. The greatly enhanced CO₂RR performance of OD-Zn-CTAB can be attributed to the increased number of active sites originating from the surface reconstruction and the formation of a favorable CTAB-modified electrode/electrolyte (E/E) interface that can efficiently adsorb and activate CO₂ while inhibiting the competitive H₂ evolution reaction.

Integrated carbon capture and conversion: A review on C2+ product mechanisms and mechanism-guided strategies

The need to reduce atmospheric CO₂ concentrations necessitates CO₂ capture technologies for conversion into stable products or long-term storage. A single pot solution that simultaneously captures and converts CO₂ could minimize additional costs and energy demands associated with CO₂ transport, compression, and transient storage. While a variety of reduction products exist, currently, only conversion to C₂₊ products including ethanol and ethylene are economically advantageous. Cu-based catalysts have the best-known performance for CO₂ electroreduction to C₂₊ products. Metal Organic Frameworks (MOFs) are touted for their carbon capture capacity. Thus, integrated Cu-based MOFs could be an ideal candidate for the one-pot capture and conversion. In this paper, we review Cu-based MOFs and MOF derivatives that have been used to synthesize C₂₊ products with the objective of understanding the mechanisms that enable synergistic capture and conversion. Furthermore, we discuss strategies based on the mechanistic insights that can be used to further enhance production. Finally, we discuss some of the challenges hindering widespread use of Cu-based MOFs and MOF derivatives along with possible solutions to overcome the challenges.

Controlling C-C coupling in electrocatalytic reduction of CO2 over Cu1-xZnx/C

From the perspective of sustainable environment and economic value, the electroreduction of CO₂ to higher order multicarbon products is more coveted than that of C₁ products, owing to their higher energy densities and a wider applicability. However, the reduction process remains extremely challenging due to the bottleneck of C-C coupling over the catalyst surfaces, and therefore designing a suitable catalyst for efficient and selective electrocatalytic reduction of CO₂ is a need of the hour. With the target of producing C₃₊ products with higher selectivity, in this study we explored the nano-alloys of Cu_1-xZn_x as electrocatalysts for CO₂ reduction. The nano-alloy Cu_1-xZn_x synthesized from the corresponding bimetallic metal organic framework materials demonstrated a gradual enhancement in the selectivity of acetone upon CO₂ electroreduction with higher doping of Zn. The Cu_1-xZn_x alloy opened up a wide possibility of fine-tuning the electronic structure by shifting the position of the d-band centre and modulating the interaction with intermediate CO and thus enhanced the selectivity of desirable products, which might not have been accessible otherwise. The postulated molecular mechanism of CO₂ electroreduction involving the desorption of the poorly adsorbed intermediate CO due to the presence of Zn and spilling over of free CO to Cu sites in the nano-alloy Cu_1-xZn_x for further C-C coupling to yield acetone was corroborated by the first principles studies.