Search

Catalytic conversion of CO2 to produce fuels and chemicals is of great importance, and the electrocatalytic CO2 reduction reaction (eCO2RR) is considered one of the most attractive pathways. Multi-carbon (C2+) products are more desirable in many cases. To date, Cu-based catalysts, especially Cu+ sites, have been found to be the most efficient for the production of C2+ products. However, the retention of Cu+ sites at high cathodic potentials in the eCO2RR remains a great challenge. In this study, we designed and synthesized CuAl-oxide-derived (CuxAly-OD, x and y are the mass percentages of Cu and Al) catalysts for the eCO2RR to C2+ products. During the eCO2RR process, the predominant Cu species changed to Cu+, and the resulting electrocatalyst showed a high faradaic efficiency (FE) of 81.6% for C2+ products in alkaline aqueous solutions. Experimental studies showed that the presence of a stable amorphous Al2O3 phase stabilized the Cu+ sites by oxidation state control, leading to high selectivity and activity for the production of C2+ products. This work provides a strategy for improving the stability of Cu+ in the catalyst to enhance the performance of the eCO2RR. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO2 by renewable electricity offers a promising way to settle excessive greenhouse gases and achieve carbon neutrality under a mild environment. Cu-based catalysts have a unique catalytic activity towards multicarbon (C2+) products in the CO2 electroreduction reaction and are widely studied to promote the corresponding selectivity and activity. Here we report a F-doped Cu (F–Cu) catalyst to improve C2+ products in CO2 electroreduction. A high C2+ product (mainly ethylene and ethanol) faradaic efficiency of 70.4% was achieved on the F–Cu catalyst with a high current density (above 400 mA cm−2) in the flow-cell system. The in situ surface enhanced Raman spectroscopy results and electrochemical performance analysis demonstrated that CO2 could be reduced into CO at low potentials and the adsorption of CO could be strengthened on F–Cu, which is beneficial to the subsequent C–C coupling step and formation of the C2+ products. [ABSTRACT FROM AUTHOR]

It is very interesting to synthesize high value-added chemicals from CO2 under mild conditions with low energy consumption. Here, we report that a novel catalyst, Zn(betaine)2Br2, can efficiently promote the cycloaddition of CO2 with epoxides to synthesize cyclic carbonates under ambient conditions (30 °C, 1 atm). DFT calculations provide important insights into the mechanism, particularly the unusual synergistic catalytic action of Zn2+, Br− and NR4+, which is the critical factor for the outstanding performance of Zn(betaine)2Br2. The unique features of the catalyst are that it is cheap, green and very easy to prepare. [ABSTRACT FROM AUTHOR]

Superamphiphilic carbon from sawdust was directly prepared in oxygen/argon. The C element is responsible for the hydrophobic nature and the O element in anhydride and carboxyl groups endows carbon with hydrophilicity. Furthermore, in the oxidation of benzyl alcohol, conversion and yield could reach 94% doubled those of blank experiments in Pickering emulsion due to superamphiphilicity of carbon. [ABSTRACT FROM AUTHOR]

Electrochemical CO 2 reduction reaction (CO 2 RR) to multicarbon (C 2+ ) products faces challenges of unsatisfactory selectivity and stability. Guided by finite element method (FEM) simulation, a nanoreactor with cavity structure can facilitate C-C coupling by enriching *CO intermediates, thus enhancing the selectivity of C 2+ products. We designed a stable carbon-based nanoreactor with cavity structure and Cu active sites. The unique geometric structure endows the carbon-based nanoreactor with a remarkable C 2+ product faradaic efficiency (80.5%) and C 2+ -to-C 1 selectivity (8.1) during the CO 2 electroreduction. Furthermore, it shows that the carbon shell could efficiently stabilize and highly disperse the Cu active sites for above 20 hours of testing. A remarkable C 2+ partial current density of-323 mA cm -2 was also achieved in a flow cell device. In situ Raman spectra and density functional theory (DFT) calculation studies validated that the *CO atop intermediates are concentrated in the nanoreactor, which reduces the free energy of C-C coupling. This work unveiled a simple catalyst design strategy that would be applied to improve C 2+ product selectivity and stability by rationalizing the geometric structures and components of catalysts., Competing Interests: The authors declare no competing interests., (This journal is © The Royal Society of Chemistry.)

The electrochemical reduction of carbon dioxide (CO 2 RR) holds great promise for sustainable energy utilization and combating global warming. However, progress has been impeded by challenges in developing stable electrocatalysts that can steer the reaction toward specific products. This study proposes a carbon shell coating protection strategy by an efficient and straightforward approach to prevent electrocatalyst reconstruction during the CO 2 RR. Utilizing a copper-based metal-organic framework as the precursor for the carbon shell, we synthesized carbon shell-coated electrocatalysts, denoted as Cu- x-y , through calcination in an N 2 atmosphere (where x and y represent different calcination temperatures and atmospheres: N 2 , H 2 , and NH 3 ). It was found that the faradaic efficiency of ethanol over the catalysts with a carbon shell could reach ∼67.8%. In addition, the catalyst could be stably used for more than 16 h, surpassing the performance of Cu-600-H 2 and Cu-600-NH 3 . Control experiments and theoretical calculations revealed that the carbon shell and Cu-C bonds played a pivotal role in stabilizing the catalyst, tuning the electron environment around Cu atoms, and promoting the formation and coupling process of CO*, ultimately favoring the reaction pathway leading to ethanol formation. This carbon shell coating strategy is valuable for developing highly efficient and selective electrocatalysts for the CO 2 RR., Competing Interests: The authors declare no competing interests., (This journal is © The Royal Society of Chemistry.)

To realize commercial CO 2 electrochemical reduction to C 2+ alcohols, the selectivity and production rate should be further improved. Establishing controllable surface sites with a favorable local environment is an interesting route to guide the C 2+ pathway. Herein, we report a room-temperature one-step synthetic strategy to fabricate a highly stable Cu aerogel as an efficient CO 2 reduction electrocatalyst. Controlling crystal growth kinetics using different reductants is an efficient strategy to modulate the nucleation and growth rate of Cu aerogels, enabling the creation of efficient surface sites for the C 2+ pathway. Over the Cu aerogel obtained by reducing Cu 2+ using a weak reductant (NH 3 ·BH 3 ), the faradaic efficiency of C 2+ products could reach 85.8% with the current density of 800 mA cm -2 at the potential of -0.91 V vs. reversible hydrogen electrode, and the C 2+ alcohol selectivity was 49.7% with a partial current density of 397.6 mA cm -2 , while the Cu aerogel prepared using a strong reductant (NaBH 4 ) was favorable to generating CO. Experimental and theoretical studies showed that the selectivity of the reaction depended strongly on the desorption and dimerization of *CO intermediates on the catalysts. The strong reductant induced a defective Cu surface that could facilitate the desorption of the *CO intermediate, subsequently producing CO, whereas the low defect Cu produced using a weak reductant could significantly enhance the selectivity for the C 2+ product by improving *CO adsorption and the C-C coupling on the catalyst. This work opens a new way for constructing efficient electrocatalysts for CO 2 electroreduction to C 2+ alcohols., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Current techno-economic evaluation manifests that the electrochemical CO 2 reduction reaction (eCO 2 RR) to CO is very promising considering its simple two-electron transfer process, minimum cost of electricity, and low separation cost. Herein, we report a Sn-modification strategy that can tune the local electronic structure of Cu with an appropriate valence. The as-prepared catalysts can alter the broad product distribution of Cu-based eCO 2 RR to predominantly generate CO. CO faradaic efficiency (FE) remained above 96% in the wide potential range of -0.5 to -0.9 V vs. the reversible hydrogen electrode (RHE) with CO partial current density up to 265 mA cm -2 . The catalyst also had remarkable stability. Operando experiments and density functional theory calculations demonstrated that the surface Cu δ + sites could be modulated and stabilized after introducing Sn. The Cu δ + sites with low positive valence were conducive to regulating the binding energy of intermediates and resulted in high CO selectivity and maintained the stability of the catalyst. Additionally, scaling up the catalyst into a membrane electrode assemble system (MEA) could achieve a high overall current of 1.3 A with exclusive and stable CO generation., Competing Interests: The authors declare no competing financial interests., (This journal is © The Royal Society of Chemistry.)

The electroreduction of CO 2 to CH 4 has attracted extensive attention. However, it is still a challenge to achieve high current density and faradaic efficiency (FE) for producing CH 4 because the reaction involves eight electrons and four protons. In this work, we designed Cu nanoparticles supported on N-doped carbon (Cu-np/NC). It was found that the catalyst exhibited outstanding performance for the electroreduction of CO 2 to CH 4 . The FE toward CH 4 could be as high as 73.4% with a high current density of 320 mA cm -2 . In addition, the mass activity could reach up to 6.4 A mg Cu -1 . Both experimental and theoretical calculations illustrated that the pyrrolic N in NC could accelerate the hydrogenation of *CO to the *CHO intermediate, resulting in high current density and excellent selectivity for CH 4 . This work conducted the first exploration of the effect of N-doped species in composites on the electrocatalytic performance of CO 2 reduction., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

It is very interesting to synthesize high value-added chemicals from CO 2 under mild conditions with low energy consumption. Here, we report that a novel catalyst, Zn(betaine) 2 Br 2 , can efficiently promote the cycloaddition of CO 2 with epoxides to synthesize cyclic carbonates under ambient conditions (30 °C, 1 atm). DFT calculations provide important insights into the mechanism, particularly the unusual synergistic catalytic action of Zn 2+ , Br - and NR 4+ , which is the critical factor for the outstanding performance of Zn(betaine) 2 Br 2 . The unique features of the catalyst are that it is cheap, green and very easy to prepare.

Powered by a renewable electricity source, electrochemical CO 2 reduction reaction is a promising solution to facilitate the carbon balance. However, it is still a challenge to achieve a desired product with commercial current density and high efficiency. Herein we designed quasi-square-shaped cadmium hydroxide nanocatalysts for CO 2 electroreduction to CO. It was discovered that the catalyst is very active and selective for the reaction. The current density could be as high as 200 mA cm -2 with a nearly 100% selectivity in a commonly used H-type cell using the ionic liquid-based electrolyte. In addition, the faradaic efficiency of CO could reach 90% at a very low overpotential of 100 mV. Density functional theory studies and control experiments reveal that the outstanding performance of the catalyst was attributed to its unique structure. It not only provides low Cd-O coordination, but also exposes high activity (002) facet, which requires lower energy for the formation of CO. Besides, the high concentration of CO can be achieved from the low concentration CO 2 via an adsorption-electrolysis device., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)