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Reducing the use of fossil fuels is critical to human society. In recent years, electrocatalytic carbon dioxide (CO2) reduction has attracted widespread attention. A suitable CO2 reduction catalyst is essential to convert CO2 into more valuable chemical products with high selectivity and efficiency. In this paper, a highly selective ZnAlCe-Ternary metal hydroxides (ZnAlCe-THs) nanocomposite electrocatalyst material was designed and prepared, and its performance as an electrocatalyst for catalytic reduction of CO2 to carbon monoxide (CO) was explored. The layered structure of ZnAlCe-THs nanocomposites facilitates electron transfer as well as CO2 and proton transfer, providing a high specific surface area for the electroactive sites of the electrocatalytic reduction reaction. At the same time, the ZnAlCe-THs catalyst generates CO at an overpotential of − 0.5 V. At − 1.2 V versus the reversible hydrogen electrode (vs. RHE), the bias current density is about 10.46 mA cm−2 with high selectivity of 89.3% Faraday efficiency. Its excellent electrochemical properties make it a good catalyst for the selective reduction of CO2 to CO. In this paper, ZnAlCe-Ternary mental hydroxides (ZnAlCe-THs) with a layered hydrotalclike structure were prepared by hydrothermal and co-precipitation methods. It showed excellent catalytic performance in the electrocatalytic reduction of carbon dioxide to carbon monoxide with a Faraday efficiency of 89.3% at − 1.2 V vs. RHE and a current density of 10.46 mA cm−2 for higher selectivity for CO. In addition, the ZnAlCe-THs catalyst is stable and it can operate for 5 h without particularly significant deactivation. [ABSTRACT FROM AUTHOR]

A homogeneous electrochemical deposition method was used in this study of CdAl nanoparticles onto CP fibers at −1.1, −1.2, −1.3, and −1.4 V vs. RHE to prepare highly active, selective, and stable CdAl-LDHs nanocatalysts. The electrochemically deposited materials exhibited extremely high CO selectivity during CO 2 RR, with the CO FE reaching 99.71% at −1.6 V vs. RHE and a partial current density of 22.13 mA cm−2. The CdAl-LDHs maintained excellent CO FE along with high CO partial current density. Remarkably, the CdAl-LDHs demonstrated outstanding electrochemical performance that exceeded most of the reported CO 2 reduction to CO electrocatalysts, maintaining stable electrocatalytic performance for more than 30 h with the FE remaining stable at about 99% and a current density at 10.05 mA cm−2 with little decay. [Display omitted] • CdAl nanoparticles with high activity, selectivity and stability were directly deposited on CP fibers by electrochemical deposition method. • The materials prepared by electrochemical deposition exhibit extremely high CO selectivity in the CO 2 RR process, with Faraday efficiency up to 99.71 %. • CdAl-LDHs can maintain the electrocatalytic performance for more than 30 h, and in this process, and the Faraday efficiency can be stable at about 99 %. Layered bimetallic hydroxides are at the forefront of current research in electrocatalytic materials. Although there is considerable research on various bimetallic hydroxides, the study of bimetallic hydroxides for electrocatalytic reduction of carbon dioxide is limited. In this paper, cadmium-aluminum layered bimetallic hydroxide nanoparticles (CdAl-LDHs) were prepared using a simple electrochemical deposition method. The prepared CdAl-LDHs was characterized in detail, and its potential application as an electrocatalyst was discussed. CdAl-LDHs prepared using different methods showed different selectivity in the electrocatalytic reduction of CO 2 to CO. The nanomaterial exhibits excellent CO selectivity in a reaction chamber using 2 %-BMIM(PF 6)(1-butyl-3-methylimidazolium hexafluorophosphate)/DMF(N-N dimethyl formamide) as the electrolyte. The CdAl-LDHs prepared by electrochemical deposition exhibited a maximum CO partial current density of 22.13 mA cm−2 with a remarkable CO Faraday efficiency (FE) of 99.71 %, which is comparable to or even higher than that of noble metal catalysts. This high selectivity for CO indicates its potential as an alternative to expensive noble metal catalysts. Moreover, the catalyst demonstrated high stability over 30 h of continuous operation with stable FE of around 99 % and a current density of around 10.5 mA cm−2, with minimal degradation during the entire reaction cycle. In addition, the catalyst showed a low HER current density of less than 0.1 mA cm−2 at all tested potentials, indicating that the catalyst maintains a high level of CO 2 conversion over the entire range of tested potentials. This suggests its great potential for industrial applications. [ABSTRACT FROM AUTHOR]

Summary: The production of CO via electrochemical CO2 reduction has been recognised as a promising technology that overcomes the environmental issues caused by global warming. It also facilitates the conversion of CO2 into energy sources. Earth‐abundant Zn is a well‐known alternative to noble metal catalysts such as Au and Ag for the electrochemical CO2 reduction to CO. In particular, Zn‐based materials in the form of nanowires are potentially applicable as electrocatalysts in the electrochemical CO2 reduction. However, the conventional methods for manufacturing the nanowire structure are difficult as they require harsh conditions such as high temperatures and excess energy. In this study, Zn‐based nanowire catalysts are prepared by the facile electrodeposition of Zn nanostructures on a substrate followed by their energy‐free solution‐phase reconstitution. Further, their electrochemical performance in the CO2 reduction is investigated in a CO2‐purged 0.5 M KHCO3 electrolyte. By optimising the deposition conditions, hexagonal Zn (h‐Zn) plates with dominant Zn(101) facets, the favoured crystal structure for CO2 reduction, are fabricated on carbon paper. Furthermore, it is found that, during the solution‐phase reconstruction over 16 hours, the h‐Zn plate transforms to a nanowire owing to the differences between the oxidation rates of different crystal facets and the formation of a hydroxide complex. The activity of the reconstructed Zn‐based nanowire catalyst is enhanced further by forming an oxide layer via thermal treatment in a H2 atmosphere. This treatment boosted the reaction kinetics, thereby enhancing the catalyst performance in the CO2 reduction. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of carbon dioxide (CO 2 ) to formate is energetically inefficient because high overpotential is required for reduction of CO 2 to formate on most traditional catalysts. In this paper, a novel nano-sized Bi-based electrocatalyst deposited on a Cu foil has been synthesized, which can be used as a cathode for electrochemical reduction of CO 2 to formate with a low overpotential (0.69 V) and a high selectivity (91.3%). The electrocatalyst can show excellent catalytic performance toward reduction of CO 2 which can probably be attributed to the nano-sized structure and the surface oxide layer. The energy efficiency for reduction of CO 2 to formate can reach to 50% when an Ir x Sn y Ru z O 2 /Ti electrode is used as anode, it is one of the highest values found in the literatures and very practicable for sustainable fuel synthesis. [ABSTRACT FROM AUTHOR]

In this paper, Ti/ZnO–Fe 2 O 3 composite derived from Ti/Schiff base intercalated ZnFe layered double hydroxides was used as thin film electrode in CO 2 photoelectroreduction. The influence of molar ratio of Ti/Fe and calcination temperature, which would affect the composites' physicochemical property and the photoelectrocatalytic performance for CO 2 reduction, were investigated in detail. The characterization results from XRD, SEM, TEM, UV-vis and BET showed that Ti/ZnO–Fe 2 O 3 composite with flower–like crystal from had small particle sizes, narrow band gap and excellent textural properties. The final product of CO 2 photoelectroreduction was methanol and the intermediates were formic acid and formaldehyde. The methanol field reached at 0.773 mmol/cm 2 after 3 h reaction with 0.5 V voltage by Ti/ZnO–Fe 2 O 3 composite with Ti/Fe = 1, calcined at 800 °C. In addition, the CO 2 photoelectroreduction pathway and the reason for highly efficient photoelectrocatalytic activity of the composite were also discussed. [ABSTRACT FROM AUTHOR]

This paper presents the experimental investigation of copper loaded carbon nanotubes (CNTs) electrocatalysts for the electrochemical reduction of carbon dioxide. The electrocatalysts were synthesized by homogeneous deposition precipitation method (HDP) using urea as precipitating agent. The prepared catalysts were characterized by TEM, SEM, XRD, XPS, BET, and FTIR for their morphology and structure. Characterization results confirm the deposition of Cu nanoparticles (3-60 nm) on CNTs. Linear sweep voltammetry (LSV) and chronoamperometry (CA) were used to investigate the activity of the as-prepared catalysts for the electrochemical reduction of carbon dioxide. The electrocatalysts reduced CO2 with high current density in the potential range 0~-3V versus SCE (standard calomel electrode). Among all catalysts tested, 20 wt. % copper loaded CNTs showed maximum activity. Gas chromatograph with TCD was used to analyze liquid phase composition. The faradaic efficiency for methanol formation was estimated to be 38.5%. [ABSTRACT FROM AUTHOR]

• Review of graphene-assisted construction strategies of both metal and non-metal based electrocatalysts. • Discussion of CO 2 RR electrocatalytic performances of various graphene − metal composites. • Overview of enhancement approaches of the graphene-based non-metal CO 2 RR catalytic activities. • Challenges and perspectives for the future development of graphene-based CO 2 RR electrocatalysts. The electrochemical conversion of the greenhouse gas, carbon dioxide (CO 2), to energy fuels and value-added chemicals presents one of the most valuable approaches to harvest pollutants and produce renewable energy. However, the stable molecular structure of CO 2 and the sluggish reaction kinetics make CO 2 reduction reaction (CO 2 RR) formidably challenging to achieve reaction rate and selectivity practical in industry. Graphene and its derivatives have been considered a group of intriguing materials to develop advanced CO 2 RR electrocatalysts due to their large specific surface area, remarkable electron transfer ability, superior stability, and easy tunability of the structure and surface properties. Herein, we comprehensively discuss the state-of-the-art electrocatalysts constructed with graphene and derivatives for active and selective CO 2 RR within the recent five years, mainly including the electrocatalysts with both metal-based (e.g., noble, non-noble, or combined thereof) and non-metal (e.g., doped, modified, defected, or composited) catalytic sites. To present the versatile, high-performance metal-based CO 2 RR electrocatalysts constructed with graphene, we further subdivide them according to the sizes, oxidation states, metal species synergies, dimensionalities, and versatility. Finally, we provide the challenges and perspectives in this emerging area of utilising CO 2 to produce various carbon-based fuels and chemicals via graphene chemistry. [ABSTRACT FROM AUTHOR]