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The composition of the catalyst layer plays an important role in the carbon dioxide reduction reaction (CO 2 RR), since it influences greatly the mass diffusion rate and the accessibility of active sites. Until now, tremendous efforts have been dedicated to the development of cathode materials with innovative characteristics, while scarce efforts have been concentrated on the study of the catalyst layer aiming at maximizing the performance of the electrodes toward the CO 2 RR. This work focuses on a full investigation of the key electrode components and their effects on the CO 2 RR performance. It is found that all key components such as Nafion binder, zinc oxide catalyst and carbon black conductor significantly affect the current density and the faradaic efficiency for carbon monoxide (CO) formation. [Display omitted] • A thorough study of the composition of a ZnO-based electrode is conducted for CO 2 RR. • All key components show significant effects on CO selectivity and production rate. • Nafion favors charge transfer while it limits electron transport and CO 2 diffusion. • Carbon black considerably increases electrical conductivity. • ZnO loading is associated with the number of active sites and their accessibility. [ABSTRACT FROM AUTHOR]

[Display omitted] • The submitted work is of great interest for the Journal Applied Energy due to its peculiar theme, the electrochemical CO 2 reduction, and for its approach in the investigation. Indeed, a complete ab initio modelling guided the experimental synthesis and testing of a molecular electrocatalyst which shows great performances for the CO2RR. • This work elucidate the possibility to activate the CO 2 through organic molecules and, moreover, shows the feasibility of this approach to be completely integrated inside a TRL 3–4 electrolysis cell. The electrochemical reduction of CO 2 to value-added products is hindered by its thermodynamic stability and by the large energy required to chemically activate the molecule. With this respect, forcing CO 2 in a non-linear geometry would induce an internal electron charge rearrangement which would facilitate further electrochemical transformations. In this work, we achieved this goal through the design of a dual function electro-organocatalyst, which exploits the ability of the imidazolate (Im-) lone pair to bind CO 2 via nucleophilic attack and then electrochemically reduce it. To give structural stability to the Im- based catalyst, the imidazoles species are incorporated into a solid structure, namely ZIF-8. Once activated by the organic Im- ligand, CO 2 is electrochemically reduced to CO when a bias is applied to ZIF-8. The catalyst proposed in our study was first devised by computer aided design based on Density functional Theory simulations and then realized in laboratory. Our results demonstrate that ZIF-8 supported on conductive CNTs presents surface Im- active sites which convert CO 2 into CO with a high faradaic efficiency (70.4 %) at −1.2 V vs reversible hydrogen electrode, by combining chemical activation with electrochemical catalysis. [ABSTRACT FROM AUTHOR]

Catalysts play a vital role in electrochemical reduction of CO 2 to valuable products. Only based on effective catalysts, CO 2 electrolysis process can be advanced toward industrial application. In this work, we present a Sb-Cu 2 O material synthesized via one-pot microwave-assisted solvothermal route. The Sb-Cu 2 O derived bimetallic catalyst achieves a highest CO selectivity of 96% and good CO partial current densities of 37.3 and 74.0 mA cm−2 at − 0.8 and − 1.2 V vs. reversible hydrogen electrode (RHE), respectively. The Sb-Cu catalyst also displays good stability at current densities ranging from 5.6 to 100 mA cm−2. Additionally, for the first time, a complete theoretical study reveals the critical roles of Sb in selective CO 2 conversion to CO on this bimetallic material, including stabilizing stepped Cu surfaces selective for the reaction, lowering energy barriers for the formation of key intermediate and favouring CO desorption. [Display omitted] • Sb-Cu 2 O material is synthesized via a one-pot microwave-assisted route. • Sb is uniformly distributed and promotes the formation of nanocrystalline Cu 2 O. • The derived Sb-Cu shows outstanding performance for the CO 2 RR to CO. • Enhancing local CO 2 concentration is demonstrated to boost CO formation rate. • Theoretical study reveals the critical roles of Sb in CO formation on Sb-Cu. [ABSTRACT FROM AUTHOR]