Electrochemical Conversion Of Carbon Dioxide Research Articles

Detection of electrocatalytical and -chemical processes by means of in situ flow NMR spectroscopy

In situ studies of electrochemical processes using NMR offer valuable information on reaction mechanisms, kinetics, and species identification, making it a powerful tool in electrochemistry research. In this study, we present the design of an in situ redox-flow NMR cell that allows for a continuous flow of liquid (electrolyte) or gas, application of electrical voltage, and recording of NMR signals. The utility of this setup is demonstrated through two case studies: electrochemical copper deposition on a gold electrode and the electrochemical conversion of carbon dioxide into hydrocarbon products. Specifically, the presence of multicarbon products containing C–C bonds generated during the electrochemical reduction reaction is confirmed in the 2H NMR spectra in the latter example. These findings highlight the ability of the in situ redox-flow NMR cell to directly monitor reaction intermediates and products, thereby enabling the elucidation of reaction mechanisms for the efficient and selective production of valuable hydrocarbon products through the conversion of CO2 into value-added chemicals. In contrast to other reported in situ NMR cells, the presented cell is suitable for multiple uses, and allows detecting NMR signals not only from exhaust products but also from those formed on the catalyst surface.

Nucleation-Controlled Production of Sub-50 nm Carbon Nanotubes through Electrochemical Conversion of Carbon Dioxide in Carbonate Molten Salt

The increasing emission of carbon dioxide worldwide has emerged as a major global concern in the context of addressing climate change. Converting CO2 to high-value carbon materials is a promising solution to capture emitted carbon for achieving carbon neutrality. Furthermore, such conversion can provide carbon nanomaterials for key industries, including the lithium battery and fuel cell industries. Here, it is shown that sub-50 nm tangled carbon nanotubes (CNTs) can be synthesized by adjusting the metaborate concentration and the current density through the electrochemical conversion of carbon dioxide in a molten carbonate salt. The metaborate ion concentration affects the product selectivity and carbon morphology, and the current density is strongly related to the particle size of in situ seed catalysts supplied by the dissolution of an Ni-Fe-Cr alloy anode. The optimized process conditions control the nucleation and growth of carbon via a tip-growth mechanism, thereby promoting the formation of sub-50 nm CNTs rather than bulky irregular carbon particles. The Raman and Brunauer–Emmett–Teller analyses showed that the properties of the prepared CNTs depended on the synthetic parameters. This study provides deep insights into the mechanism underlying carbon synthesis through the electrochemical reduction of a molten carbonate salt.

High-efficient carbon dioxide-to-formate conversion on Bi5O7NO3 by tuning the exposure of crystal plane during reconstruction in electrolysis

The electrochemical conversion of carbon dioxide into formic acid offers an effective approach for utilizing carbon dioxide resources. Bismuth (Bi)-based catalysts have garnered significant attention in this field. However, designing high-performance Bi-based catalysts is challenging due to difficulties in accurately adjusting the reconstruction of such catalysts during electrolysis. In this study, we reported that nitrate ions positively influence the reconstruction of Bi5O7NO3 (BON), thereby outperforming Bi2O3 during ECO2RR. BON attained a Faraday efficiency of formate (FEHCOOH) and partial current density of 95.3% and 25.1mA/cm2 at -0.9V vs RHE, respectively, surpassing the performance of Bi2O3 (90.2% and 15.4mA/cm2). The layered structure of BON mitigates Bi agglomeration during electrolysis, thus providing a large number of active sites. The presence of nitrate ions promotes exposure to abundant Bi(110) and Bi(015), whereas only the Bi(012) plane forms in Bi2O3 during electrolysis. In-situ ATR FTIR results indicate that both BON and Bi2O3 follow the same pathway for formate formation. Nevertheless, the high-index planes (015) cause the Bi derived from BON to remain in an electron defect state, which increases the adsorption of *CO2. In addition, Bi(110) plane has effectively lower the energy barriers for *OCHO production than Bi(012) plane. The Bi(015) and Bi(110) planes enhance the adsorption of *CO2 intermediates and reduce the energy barrier for *OCHO formation, respectively, which contributes to the improved ECO2RR activity of BON.

1 nm Tin Oxide Cluster for the Electrochemical Conversion of Carbon Dioxide to Formate at Low Overpotential

Due to its cost-effectiveness and high product selectivity, tin oxide has been regarded as a promising catalyst for the electrochemical conversion of CO2 to formate. However, formate production is hindered by the high overpotential; there is a need to reduce the overpotential to enhance energy efficiency and lower electricity cost for the implementation of carbon utilization technology. Here, we report a facile synthesis method for 1 nm-sized SnO2 cluster catalysts, which can be used for CO2-to-formate conversion. SnO2 clusters were prepared through impregnation of porous carbon with a tin precursor solution. The SnO2 clusters showed a low overpotential, generating a current density of 10 mA cm-2 at a potential of -0.34 V vs. RHE in 1 M KOH. They also achieved high Faradaic efficiencies of 90.5% and 81.5% at 200 and 300 mA cm−2, respectively. Their electrocatalytic performance was strongly dependent on the annealing conditions, which affected the particle size, electrochemical active surface area, and metal oxidation state. This paper presents a versatile method for synthesizing metal oxide cluster catalysts, apart from providing insights into the catalytic activity for the electrochemical conversion of CO2 to formate.

Role of single-atom alloy catalysts in electrochemical conversion of carbon dioxide: A theoretical study

Atomic-scale understanding of C-C coupling in the electrocatalytic conversion of carbon dioxide (CO2) into valuable C2 chemicals remains elusive. Herein, we selected Group VIII and IB transition metals as active sites incorporated into the Cu(100) surface to construct single-atom alloy catalysts. The stability, selectivity, and activity of a series of catalysts were calculated using density functional theory. Fe, Co, Ni, Ru/Cu(100) exhibit the potential as candidates to generate C2 products and suppress the hydrogen evolution reaction (HER). The reaction proceeds through the reduction of CO2 to key intermediates *CO and *CHO, which undergoes C-C coupling to generate *CO-CHO, subsequently undergoing different protonation processes to yield diverse C2 products. The rate-determining step for Fe, Co, Ni, and Ru/Cu(100), is the hydrogenation of *CO, with a comparable energy barrier of 0.8 eV. Moreover, Fe and Co/Cu(100) favor the formation of C2H4 as the primary product, while Ni and Ru/Cu(100) predominantly produce CH3COOH.

Mechanistic Basis of Conductivity in Carbon Dioxide-Expanded Electrolytes: A Joint Experimental-Theoretical Study.

Electrolyte conductivity contributes to the efficiency of devices for electrochemical conversion of carbon dioxide (CO2) into useful chemicals, but the effect of the dissolution of CO2 gas on conductivity has received little attention. Here, we report a joint experimental-theoretical study of the properties of acetonitrile-based CO2-expanded electrolytes (CXEs) that contain high concentrations of CO2 (up to 12 M), achieved by CO2 pressurization. Cyclic voltammetry data and paired simulations show that high concentrations of dissolved CO2 do not impede the kinetics of outer-sphere electron transfer but decrease the solution conductivity at higher pressures. In contrast with conventional behaviors, Jones reactor-based measurements of conductivity show a nonmonotonic dependence on CO2 pressure: a plateau region of constant conductivity up to ca. 4 M CO2 and a region showing reduced conductivity at higher [CO2]. Molecular dynamics simulations reveal that while the intrinsic ionic strength decreases as [CO2] increases, there is a concomitant increase in ionic mobility upon CO2 addition that contributes to stable solution conductivities up to 4 M CO2. Taken together, these results shed light on the mechanisms underpinning electrolyte conductivity in the presence of CO2 and reveal that the dissolution of CO2, although nonpolar by nature, can be leveraged to improve mass transport rates, a result of fundamental and practical significance that could impact the design of next-generation systems for CO2 conversion. Additionally, these results show that conditions in which ample CO2 is available at the electrode surface are achievable without sacrificing the conductivity needed to reach high electrocatalytic currents.

Recent advances in nanoscale engineering of Pd-based electrocatalysts for selective CO2 electroreduction to formic acid/formate

Electrochemical conversion of carbon dioxide (CO2) into high-value chemicals and fuels driven by electricity derived from renewable energy has been recognized as a promising strategy to achieve carbon neutrality and create sustainable energy. Particularly from the viewpoint of the product values and the economic viability, selective CO2 reduction to formic acid/formate has shown great promise. Palladium (Pd) has been demonstrated as the only metal that can produce formic acid/formate perfectly near the equilibrium potential; yet, it still suffers from CO poisoning, poor stability and competitive CO pathway at high overpotentials. Herein, recent progress of Pd-based electrocatalysts for selective CO2 electroreduction and their mechanistic understanding are reviewed. First, the fundamentals of electrochemical CO2 reduction and the reaction pathway of formic acid/formate on Pd are presented. Then, recent advances in the rational design and nanoscale engineering strategies of Pd-based electrocatalysts for further improving CO2 reduction activity and selectivity to formic acid/formate product, including size control, morphology and shape control, alloying, heteroatom doping, surface-strain engineering, and phase control, are discussed from the perspectives of both experimental and computational aspects. Finally, we discuss the pertinent challenges and describe the future prospects and opportunities in terms of the development of electrocatalysts, electrolyzers and characterization techniques in this research field.

Accelerated screening of gas diffusion electrodes for carbon dioxide reduction

The electrochemical conversion of carbon dioxide to chemicals and fuels is expected to be a key sustainability technology. Electrochemical carbon dioxide reduction technologies are challenged by several factors, including the...

Grain boundary and interface interaction of metal (copper/indium) oxides to boost efficient electrocatalytic carbon dioxide reduction into syngas

Electrochemical conversion of carbon dioxide (CO2) into syngas is considered a promising approach to mitigate global warming and achieve the recycling of carbon resources. In this work, a series of core–shell metal (copper/indium) oxides with abundant grain boundaries (GBs) between the amorphous In2O3 and cubic Cu2O have been prepared by template-assisted co-precipitation method and tested for the synthesis of syngas by electrochemical CO2 reduction reaction (CO2RR). The phases of Cu2O and In2O3 are independent in bimetallic oxides and do not form any alloy oxidation phase, thus Cu2O and In2O3 can maintain their crystal structure and chemical properties in bimetallic oxides. The Cu2O and In2O3 would been completely reduced to metallic Cu and In during CO2RR. The derived copper/indium possesses the maximum FE of CO (80 %) at −0.77 V vs. reversible hydrogen electrode (RHE) and a good stability of 10 h in an H-type cell. Further applied the copper/indium oxide in the MEA reactor, the FE of CO is more than 80 % at 2.6 V and the total FE of syngas is near 100 % at all applied potentials. More importantly, the H2/CO ratios can be tuned from 1/1 to 1/4 by changing the applied voltages in MEA. Therefore, this study provides a promising strategy to promote the electrocatalytic CO2RR conversion by creating abundant grain boundaries in bimetallic oxides to regulate the ratio of H2/CO.

In Situ STM Investigations of Cu(100) and Bimetallic Ag/Cu(100) Model Catalysts for CO2 Electroreduction in Bicarbonate Solution

The electrochemical conversion of carbon dioxide (CO2RR) to valuable chemicals and fuels plays a crucial role in the sustainable energy economy as it represents a promising potential for the renewable energy storage as well as closing the carbon loop.[1,2] Thus, the design and development of a highly efficient and selective electrocatalyst for CO2RR has become a topic of great importance in recent years. Among elemental metals, copper exhibits unique catalytic behaviour to reduce CO2 towards multi-carbon products with reasonable Faradaic efficiency due to its moderate CO-binding energy.[3,4] However, the selectivity and activity of pure copper is still far away for a practical application. The integration of a secondary metal species provides a promising strategy to improve the catalytical performance of the copper catalyst. Combination with silver is particularly interesting for such bimetallic catalysts, since Ag is a highly efficient catalyst for CO2RR to CO, probably the most important intermediate in the CO2RR, and has been shown to promote the formation of multi-carbon products.[5]Here, we present in situ scanning tunnelling microscopy studies of well-defined Cu and AgCu electrodes in CO2-satured 0.1 M KHCO3, which is one of the most common electrolytes for CO2 electroreduction. For Cu(100) in the double layer potential range, coexistence of two ordered (bi)carbonate adlayer phases was observed (Fig. 1a,b, published in [6]). These adlayer phases have a highly complex structure, exhibit dynamic fluctuations, and undergo a potential dependent order-disorder transition at about 0 V vs. the reversible hydrogen electrode. Detailed density functional calculations reveal that the observed layer is composed of carbonate and water that coadsorb on the electrode surface, underlining the key role of water in the stabilization of the (bi)carbonate adlayers.[6]Upon decreasing the potential to the onset of CO2RR, the formation of Cu nanoclusters is observed on the Cu(100) surfaces by in situ STM. This surface restructuring can be assigned to the influence of CO intermediates formed in the CO2RR. Upon subsequent increase of the potential back into the double layer range, the clusters disperse, resulting in a highly disordered interface structure that contains Cu adatoms, (bi)carbonates, and further molecular adsorbates. This irreversible change of the molecular-scale electrode surface is supported by spectroscopic results.AgCu bimetallic model catalysts were prepared by electrodeposition of submonolayer Ag coverage on Cu(100) in 0.1 M H2SO4. Silver forms islands on Cu(100) with a hexagonal quasi-Ag(111) atomic lattice. After the preparation and characterization of the Ag-decorated Cu(100), the electrolyte was exchanged under potential control to 0.1 M KHCO3. The electrolyte exchange results in the distinct restructuring on the surface in the double layer potential range, in which the islands develop a strongly anisotropic shape. In addition, appearance of new islands and a reduced surface mobility are observed. Furthermore, in contrast to the Ag-free Cu(100), high-resolution STM images show a disordered molecular adlayer.Our results demonstrate the pronounced role of adsorbed (bi)carbonate at the catalyst/electrolyte interface and its impact on the surface morphology and dynamics already at potentials in the double layer regime. These adsorbate-induced structural changes need to be considered for a fundamental understanding and rational design of electrocatalysts for CO2RR.The Authors gratefully acknowledge financial support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) via SPP 2080, project no. 327886311.

Advanced Catalyst Design and Reactor Configuration Upgrade in Electrochemical Carbon Dioxide Conversion.

Electrochemical carbon dioxide reduction reaction (CO2 RR) driven by renewable energy shows great promise in mitigating and potentially reversing the devastating effects of anthropogenic climate change and environmental degradation. The simultaneous synthesis of energy-dense chemicals can meet global energy demand while decoupling emissions from economic growth. However, the development of CO2 RR technology faces challenges in catalyst discovery and device optimization that hinder their industrial implementation. In this contribution, a comprehensive overview of the current state of CO2 RR research is provided, starting with the background and motivation for this technology, followed by the fundamentals and evaluated metrics. Then the underlying design principles of electrocatalysts are discussed, emphasizing their structure-performance correlations and advanced electrochemical assembly cells that can increase CO2 RR selectivity and throughput. Finally, the review looks to the future and identifies opportunities for innovation in mechanism discovery, material screening strategies, and device assemblies to move toward a carbon-neutral society.

Pulsed Electrolysis Promotes CO2 Reduction to Ethanol on Heterostructured Cu2O/Ag Catalysts.

The electrochemical conversion of carbon dioxide (CO2)into ethanol with high added value has attracted increasing attention. Here, an efficient catalyst with abundant Cu2O/Ag interfaces for ethanol production under pulsed CO2 electrolysis is reported, which is composed of Cu2O hollow nanospheres loaded with Ag nanoparticles (named as se-Cu2O/Ag). The CO2-to-ethanol Faradaic efficiency is prominently improved to 46.3% at a partial current density up to 417mAcm-2 under pulsed electrolysis conditions in a neutral flow cell, notably outperforming conventional Cu catalysts during static electrolysis. In situ spectroscopy reveals the stabilized Cu+ species of se-Cu2O/Ag during pulsed electrolysis and the enhanced adsorbed CO intermediate(*CO)coverage on the heterostructured catalyst. Density functional theory (DFT) calculations further confirm that the Cu2O/Ag heterostructure stabilizes the *CO intermediate and promotes the coupling of *CO and adsorbed CH intermediate (*CH). Meanwhile, the stable Cu+ species under pulsed electrolysis favor the hydrogenation of adsorbed HCCOH intermediate (*HCCOH) to adsorbed HCCHOH intermediate (*HCCHOH) on the pathway to ethanol. The synergistic effect between the enhanced generation of *CO on Cu2O/Ag and regenerated Cu+ species under pulsed electrolysis steers the reaction pathway toward ethanol. This work provides some insights into selective ethanol production from CO2 electroreduction via combined catalyst design and non-steady state electrolysis.

Recent Progress and Perspective of the Electrochemical Conversion of Carbon Dioxide to Alcohols

Recent Progress and Perspective of the Electrochemical Conversion of Carbon Dioxide to Alcohols

(Invited) Successes and Bottlenecks in Scaling CO2 and CO Electrolysis for Commercial Demonstration

The electrochemical conversion of carbon dioxide or carbon monoxide allows for the simultaneous production of value-added chemical feedstocks with greenhouse gas emission mitigation. Scalable CO2/CO reduction requires electrolyzers that operate with high current densities, efficiencies, durabilities, and product selectivities for carbon-containing products of high market value or size (e.g. carbon monoxide (syngas), formic acid, methane, ethylene, ethanol, and 1-propanol), with the potential for some of the resulting products to be industrially upcycled to higher-order hydrocarbons. In this talk, an overview of Shell's recent efforts in derisking these electrochemical processes are presented, as well as a discussion of persistent bottlenecks that must be overcome for commercially viable demonstrations to be implemented in the near future.

A Computational Model to Optimize the Electrochemical Reduction of CO2 to Formic Acid Using an Enzymatic Catalyst

This work documents the development and subsequent analysis of a transient electrochemical model to predict the electrochemical conversion of CO2 to formic acid (FA) using an enzymatic catalyst. FA has been of recent interest for its applications in hydrogen storage and formic acid-based fuel cells [1]. This process uses an electrochemical charge mediator, commonly methyl viologen (MV) or ethyl viologen (EV) [2], which is initially reduced to a more negative species (i.e. from EV2+ to EV+), then re-oxidized upon reacting with the enzymatic catalyst to produce FA (as HCOO-) from CO2 and protons from the anode.Using an enzymatic catalyst can enable greater selectivity to a particular carbon product compared to traditional metal-based catalysts, which can produce an array of different products [3]. The model was developed in conjunction with experimental investigation to serve as a benchmark for the optimal product conversion of CO2 assuming a stable solution pH and catalyst stability. The model employs transport-based equations for each ionic species of the charge carrier, which will vary based on the initial concentration selected and the applied voltage. Kinetic parameters to determine reaction values are fit to align with existing experimental data.The model uses Butler-Volmer kinetics to estimate the total current in the system as a function of the applied voltage and as a function of estimated experimental parameters. A bulk solution is considered for the electrolytes, but species concentrations are varied across a small diffusion layer (~50 um) between the electrolyte and electrode [4]. For predicting the conversion of CO2 into FA using the enzymatic catalyst and charge carrier species, Michaelis-Menten kinetics are used with appropriate catalyst parameters derived using sampling reactions with a known potassium formate solution and UV-vis spectroscopy.Among the products formed, molecular O2 is factored into the model as it will adversely limit the maximum current in the cell at higher applied voltage, and subsequently will limit the rate of production and efficiency. An O2 scavenger, such as sodium thiosulfate, can limit the contribution of molecular oxygen in the solution, but will not eliminate it. The model assumes that pH remains constant due to the presence of electrolyte buffer in the solution, although the influx of protons will cause a drop in the pH if not immediately converted to FA, and this more acidic solution has been shown to be a significant limitation due to the performance and stability of the catalyst.The results can be analyzed as a function of multiple parameters and operating conditions, although among the most interesting to study are those for the applied voltage and initial charge carrier concentration. There, it can be shown on contour plots that optimal regions for efficiency exist around -0.8 to -1.1 V (vs. Ag/AgCl), and charge carrier concentrations of 0.1 – 10 mM. The trends obtained are in alignment with what has previously been hypothesized [2] but can now also be analyzed in conjunction with other experimental parameters, including the design (sizing) of the electrochemical cell.The primary benefits of the model are in (1) predicting optimal performance when experimental imperfections are removed, (2) rapidly predicting a range of product selectivity and efficiency due to limited resources used to run experiments, primarily for the catalyst, and (3) providing a templating a template with which to iterate upon and consider other value added products, by altering parameters to account for a different catalyst, electrolyte, or charge mediator. The model is presently being developed to include provisions for operating in a flow cell reactor, where considerations to flow rate must be considered and time delay between reduction and production cells. To best match with existing experimental data, additional effects such as pH deterioration and variations in the kinetics with voltage (which can be investigated by cyclic voltammetry experiments) will need to be considered. REFERENCES: Singh AK, Singh S, Kumar A. Hydrogen energy future with formic acid: a renewable chemical hydrogen storage system. Catalysis Science & Technology. 2016;6(1):12-40.Moreno D, Thompson J, Omosebi A, Landon J, Liu K. Electrochemical analysis of charge mediator product composition through transient model and experimental validation. Journal of Applied Electrochemistry. 2022 Nov;52(11):1573-84.Ikeyama S, Amao Y. An Artificial Co‐enzyme Based on the Viologen Skeleton for Highly Efficient CO2 Reduction to Formic Acid with Formate Dehydrogenase. ChemCatChem. 2017 Mar 8;9(5):833-8.Morrison AR, van Beusekom V, Ramdin M, van den Broeke LJ, Vlugt TJ, de Jong W. Modeling the electrochemical conversion of carbon dioxide to formic acid or formate at elevated pressures. Journal of The Electrochemical Society. 2019 Feb 12;166(4):E77. Figure 1

(Invited) Hybrid Mixed-Metal-Oxide-Based Catalytic Systems for Efficient Electroreduction of Carbon Dioxide

Of particular interest to the preparation of advanced catalytic materials is efficient utilization of nanosized materials with well-defined composition, structure and thickness that exhibit desirable electrocatalytic properties. There has been growing interest in the electrochemical conversion of carbon dioxide (a potent greenhouse gas and a contributor to global climate change) to useful carbon-based fuels or chemicals. Given the fact that the CO2 molecule is very stable, its electroreduction processes are characterized by large over-potentials. It is often postulated that, during electroreduction, the rate limiting step is the protonation of the adsorbed CO product to form the CHO adsorbate. In this respect, the proton availability and its mobility at the electrochemical interface has to be addressed. On the other hand, competition between such parallel processes as hydrogen evolution and carbon dioxide reduction has also to be considered.We explore here the ability of polynuclear transition metal oxide based systems to function as cocatalysts and to stabilize and activate metal nanocenters. Here certain nanostructured metal oxides of zirconium, titanium, molybdenum or tungsten have been demonstrated to influence supported catalytic metal sites in ways other than simple dispersion over electrode area. Evidence is presented that the support can modify activity (presumably electronic nature) of catalytic metal nanoparticles (e.g. Cu, Ru), thus affecting their chemisorptive and catalytic properties during CO2-reduction. Metal oxide (WO3, MoO3, TiO2) nanostructures can generate highly reactive –OH groups at electrocatalytic interface.Evidence is presented that the support can modify activity (presumably electronic nature) of catalytic metal nanoparticles (e.g. Cu, Pd), thus affecting their chemisorptive properties. Metal oxide (ZrO2, WO3) nanospecies can generate –OH groups at electrocatalytic interface. Our electrocatalytic results with copper nanostructures over-coated with ZrO2 or WO3 nanostructures imply the systems’ improved selectivity toward CO2-reduction relative to the competitive hydrogen evolution as well as the lower tendency of copper sites to undergo poisoning.

Surface morphology-assisted electrochemical conversion of carbon dioxide to formic acid via nanocrystalline boron-doped diamond electrodes

Due to its unmatched corrosion stability and overall versatility, boron-doped diamond (BDD) has superb potential as an electrode material for the production of valuable chemicals via electrochemical reduction of carbon dioxide (CO2). To advance its practical application, it is necessary to explore ways to achieve cost-effective fabrication of BDD electrodes, which can enable significant selectivity for product formation during CO2 electroreduction. Here, BDD electrodes of nanocrystalline form were fabricated employing two distinct chemical vapor deposition (CVD) techniques, which allow for substantial upscaling of electrode dimensions to match industrial/wafer-size standards. Thin (<400 nm) nanocrystalline BDD layers were fabricated at various synthesis temperatures to investigate its effect on the electrical, structural, and electrochemical characteristics. Furthermore, modification of the BDD layer crystallinity and morphology has been performed to significantly alter the overall electrode structure and sp3/sp2-carbon phase-composition. Finally, when employed as cathodes in electrochemical CO2 reduction, nanocrystalline BDD electrodes of modified structure demonstrated enhanced values of faradaic efficiency (FE) towards production of formic acid (HCOOH), surpassing FEHCOOH values observed for microcrystalline form of BDD cathodes. Reported findings present a basis for further development of BDD cathodes, including their design, structure, and composition, which leverages the advantages of scalable and cost-effective synthesis of BDD electrodes.

The origins of catalytic selectivity for the electrochemical conversion of carbon dioxide to methanol

The origins of catalytic selectivity for the electrochemical conversion of carbon dioxide to methanol

Advances in electrolyzer design and development for electrochemical CO2 reduction

AbstractIn view of global energy transition and environmental issues, electrochemical conversion of carbon dioxide (CO2) to high value‐added chemicals by using clean renewable electricity, as an advanced carbon capture, utilization and storage (CCUS) technology, demonstrates a promising approach to reach the carbon neutrality with additional economic benefits as well. Over the past decade, various new valid catalysts in electrochemical CO2 reduction (ECO2R) have been designed and intensively investigated. Unfortunately, constructing appropriate ECO2R electrolyzer with high conversion rate and long‐term stability to unleash the full potential benefits of electrocatalysts remains a recognized challenge, especially as it has not yet attracted attention. This review summarizes the progress of ECO2R reactor and their corresponding structure characteristics/ electrochemical performance. Besides, the current challenges and bottlenecks of CO2RR reactor are discussed. We aim to introduce the advances in ECO2R electrolyzer in detail to offer enlightenment for large‐scale industrial application of ECO2R.image

Gas penetrating hollow fiber Bi with contractive bond enables industry-level CO2 electroreduction

Electrochemical conversion of carbon dioxide (CO2) to valuable fuels driven by renewable electricity exhibits significant potential for achieving carbon neutrality. Bismuth (Bi) possesses the reliable capability of electrocatalyzing CO2 to formate, and high formate faradaic efficiencies have been realized over Bi-based catalysts, but industry-level large current densities with high conversion rates at mild conditions remain challenging yet. Herein we present a bismuth hollow fiber (Bi HF) as a gas penetration electrode (GPE) that efficiently reduces CO2 with a formate faradaic efficiency of 93% and a current density of 1.13 A cm−2 at − 1.26 V (vs. RHE), corresponding to a CO2 conversion rate of 37% under ambient temperature and pressure. Finite element analysis (FEA) and density functional theory (DFT) demonstrate that the synergetic combination of unlimited CO2 feeding to triphasic interface reactions and selective reduction induced by contractive Bi-Bi bond is responsible for the superior activity of Bi HF.