Selective CO 2 electroreduction to C 2 H 4 on porous Cu films synthesized by sacrificial support method

Carbon-Supported Nano-Dispersed Metallic Copper Derived From Carbonization of MOF-199 for Electrocatalytic CO2 Reduction

CO2 emissions and accumulation in the ecosystem have exacerbated climate change and increased the global temperature. This study focused on the activation of hydrothermally synthesized Cu metal-organic framework (MOF-199) with potassium citrate (C6H5K3O7) to produce MOF-derived carbon incorporated with nano-dispersed metallic Cu and oxidative Cu species to facilitate electrochemical CO2 reduction. Among all MOF samples, the resulting MOF-derived carbon, activated by C6H5K3O7, demonstrated the highest electrocatalytic current and lowest charge transfer resistance, achieving a Faradaic efficiency exceeding 50% for the production of acetic acid (CH3COOH) at an applied potential of - 1.1 V (vs RHE). The addition of C6H5K3O7 during preparation endowed the MOF-derived C with a mesoporous structure, thereby enhancing CO2 adsorption and activation. A proposed reaction pathway suggested that the generation of nano-dispersed metallic Cu is critical for forming Cu─C bonds for producing CH3COOH. This study indicates that Cu-containing MOF-derived carbon with beneficial properties for electrocatalytic applications owing to its nanoispersed Cu features could be readily synthesized.

Strategies for Improved Electrochemical CO2 Reduction to Value-added Products by Highly Anticipated Copper-based Nanoarchitectures

Uncontrolled CO₂ emission from various industrial and domestic sources is a considerable threat to environmental sustainability. Scientists are trying to develop multiple approaches to not only reduce CO₂ emissions but also utilize this potent pollutant to get economically feasible products. The electrochemical reduction of CO₂ (ERC) is one way to effectively convert CO₂ to more useful products (ranging from C1 to C5). Nevertheless, this process is kinetically hindered and less selective towards a specific product and, consequently, requires an efficient electrocatalyst with characteristics like selectivity, stability, reusability, low cost, and environmentally benign. Owing to specified commercial features, copper (Cu)-based materials are highly anticipated and widely investigated for the last two decades. However, their non-modified polycrystalline Cu forms usually lack selectivity and lower overpotential of CO₂ reduction. Therefore, extensive research is in progress to induce various alterations ranging from morphological and surface chemistry tuning to structural and optoelectrical characteristics modifications. This review provides an overview of those strategies to improve the CO₂ conversion efficiency through Cu-based ERC into valuable C1, C2_, and higher molecular weight hydrocarbons. The thermodynamics and kinetics of CO₂ reduction via Cu-based electrocatalysts are discussed in detail with the support of the first principle DFT-based models. In the last portion of the review, the reported mechanisms for various products are summarized, with a short overview of the outlook. This review is expected to provide important basics as well as advanced information for experienced as well as new researchers to develop various strategies for Cu and related materials to achieve improved ERC.

Development of self-supported 3D microporous solder alloy electrodes for scalable CO2 electroreduction to formate

The overpotential decreased by 0.1 V for self-supported 3D micro-porous electrodes as compared to the flat surface electrodes for the CO₂RR to formate.

High Selectivity Toward C2H4 Production over Cu Particles Supported by Butterfly-Wing-Derived Carbon Frameworks

Converting carbon dioxide to useful C2 chemicals in a selective and efficient manner remains a major challenge in renewable and sustainable energy research. Herein, we adopt butterfly wings to assist the preparation of an electrocatalyst containing monodispersed Cu particles supported by nitrogen-doped carbon frameworks for an efficient reduction of CO₂. Benefiting from structure advantages and the synergistic effect between nitrogen dopants and stepped surface-rich Cu particles, the resulting catalyst exhibited a high faradic efficiency of 63.7 ± 1.4% for ethylene production (corresponding to an ethylene/methane products' ratio of 57.9 ± 5.4) and an excellent durability (∼100% retention after 24 h). This work presents some guidelines for the rational design and accurate modulation of metal heterocatalysts for high selectivity toward ethylene from CO₂ electroreduction.

Tailoring gas-phase CO2 electroreduction selectivity to hydrocarbons at Cu nanoparticles

Copper-based surfaces appear as the most active catalysts for CO₂ electroreduction to hydrocarbons, even though formation rates and efficiencies still need to be improved. The aim of the present work is to evaluate the continuous gas-phase CO₂ electroreduction to hydrocarbons (i.e. ethylene and methane) at copper nanoparticulated-based surfaces, paying attention to particle size influence (ranging from 25-80 nm) on reaction productivity, selectivity, and Faraday efficiency (FE) for CO₂ conversion. The effect of the current density and the presence of a microporous layer within the working electrode are then evaluated. Copper-based gas diffusion electrodes are prepared by airbrushing the catalytic ink onto carbon supports, which are then coupled to a cation exchange membrane (Nafion) in a membrane electrode assembly. The results show that the use of smaller copper nanoparticles (25 nm) leads to a higher ethylene production (1148 μmol m^-2 s^-1) with a remarkable high FE (92.8%), at the same time, diminishing the competitive hydrogen evolution reaction in terms of FE. This work demonstrates the importance of nanoparticle size on reaction selectivity, which may be of help to design enhanced electrocatalytic materials for CO₂ valorization to hydrocarbons.