Carbon Dioxide Reduction Reaction Research Articles

Tuning Carbon Dioxide Reduction Reaction Selectivity of Bi Single-Atom Electrocatalysts with Controlled Coordination Environments.

Control over product selectivity of the electrocatalytic CO2 reduction reaction (CO2 RR) is a crucial challenge for the sustainable production of carbon-based chemical feedstocks. In this regard, single-atom catalysts (SACs) are promising materials due to their tunable coordination environments, which could enable tailored catalytic activities and selectivities, as well as new insights into structure-activity relationships. However, direct evidence for selectivity control via systematic tuning of the SAC coordination environment is scarce. In this work, we have synthesized two differently coordinated Bi SACs anchored to the same host material (carbon black) and characterized their CO2 RR activities and selectivities. We find that oxophilic, oxygen-coordinated Bi atoms produce HCOOH, while nitrogen-coordinated Bi atoms generate CO. Importantly, use of the same support material assured that alternation of the coordination environment is the dominant factor for controlling the CO2 RR product selectivity. Overall, this work demonstrates the structure-activity relationship of Bi SACs, which can be utilized to establish control over CO2 RR product distributions, and highlights the promise for engineering atomic coordination environments of SACs to tune reaction pathways.

Prediction of M3 B4 -type MBenes as Promising Catalysts for CO2 Capture and Reduction.

The rational design of novel catalysts with high activity and selectivity for carbon dioxide reduction reaction (CO2 RR) is highly desired. In this work, we have extensive investigations on the properties of two-dimensional transition metal borides (MBenes) to achieve efficient CO2 capture and reduction through first-principles calculations. The results show that all the investigated M3 B4 -type MBene exhibit remarkable CO2 capture and activation abilities, which proved to be derived from the lone pair of electrons on the MBene surface. Then, we emphasize that the investigated MBenes can further selectively reduce activated CO2 to CH4 . Moreover, a new linear scaling relationship of the adsorption energies of potential-determining intermediates (*OCH2 O and *HOCH2 O) versus ΔG(*OCHO) has been established, where the CO2 RR limiting potentials on MBenes are determined by the different fitting slopes of ΔG(*OCH2 O) and ΔG(*HOCHO), allowing significantly lower limiting potentials to be achieved compared to transition metals. Especially, two promising CO2 RR catalysts (Mo3 B4 and Cr3 B4 MBene) exist quite low limiting potentials of -0.48 V and -0.66 V, as well as competitive selectivity concerning hydrogen evolution reactions have been identified. Our research results make future advances in CO2 capture by MBenes easier and exploit the applications of Mo3 B4 and Cr3 B4 MBenes as novel CO2 RR catalysts.

Plasmonic‐assisted Electrocatalysis for CO2 Reduction Reaction

AbstractIntegrating plasmonic features as an emerging strategy for enhancing electrocatalysis for the carbon dioxide reduction reaction (CO2RR). The key parameters responsible for the enhanced electrocatalysis performance are the local heating, the hot carriers, and near‐field enhancement induced by localized surface plasmon resonance (LSPR, that is, plasmonic) excitation. This review provides a concise overview of the fundamental mechanism of CO2RR, detailing the generation and decay of plasmonic and the energy transfer dynamics between plasmonic nanostructures and adsorbates. It further involves recent progress in plasmonic‐assisted electrocatalysis for CO2RR, including experimental and theoretical research to decipher plasmonic mechanisms. Finally, it ends with an insightful discussion of the existing challenges and potential future directions in this field.

Immobilized Tetraalkylammonium Cations Enable Metal-free CO2 Electroreduction in Acid and Pure Water.

Carbon dioxide reduction reaction (CO2 RR) provides an efficient pathway to convert CO2 into desirable products, yet its commercialization is greatly hindered by the huge energy cost due to CO2 loss and regeneration. Performing CO2 RR under acidic conditions containing alkali cations can potentially address the issue, but still causes (bi)carbonate deposition at high current densities, compromising product Faradaic efficiencies (FEs) in present-day acid-fed membrane electrode assemblies. Herein, we present a strategy using a positively charged polyelectrolyte-poly(diallyldimethylammonium) immobilized on graphene oxide via electrostatic interactions to displace alkali cations. This enables a FE of 85 %, a carbon efficiency of 93 %, and an energy efficiency (EE) of 35 % for CO at 100 mA cm-2 on modified Ag catalysts in acid. In a pure-water-fed reactor, we obtained a 78 % CO FE with a 30 % EE at 100 mA cm-2 at 40 °C. All the performance metrics are comparable to or even exceed those attained in the presence of alkali metal cations.

A Sulfur-Doped Copper Catalyst with Efficient Electrocatalytic Formate Generation during the Electrochemical Carbon Dioxide Reduction Reaction.

Catalysts involving post-transition metals have shown almost invincible performance on generating formate in electrochemical CO2 reduction reaction (CO2 RR). Conversely, Cu without post-transition metals has struggled to achieve comparable activity. In this study, a sulfur (S)-doped-copper (Cu)-based catalyst is developed, exhibiting excellent performance in formate generation with a maximum Faradaic efficiency of 92 % and a partial current density of 321 mA cm-2 . Ex situ structural elucidations reveal the presence of abundant grain boundaries and high retention of S-S bonds from the covellite phase during CO2 RR. Furthermore, thermodynamic calculations demonstrate that S-S bonds can moderate the binding energies with various intermediates, further improving the activity of the formate pathway. This work is significant in modifying a low-cost catalyst (Cu) with a non-metallic element (S) to achieve comparable performance to mainstream catalysts for formate generation in industrial grade.

Molecular understanding of the critical role of alkali metal cations in initiating CO2 electroreduction on Cu(100) surface

Molecular understanding of the solid–liquid interface is challenging but essential to elucidate the role of the environment on the kinetics of electrochemical reactions. Alkali metal cations (M+), as a vital component at the interface, are found to be necessary for the initiation of carbon dioxide reduction reaction (CO2RR) on coinage metals, and the activity and selectivity of CO2RR could be further enhanced with the cation changing from Li+ to Cs+, while the underlying mechanisms are not well understood. Herein, using ab initio molecular dynamics simulations with explicit solvation and enhanced sampling methods, we systematically investigate the role of M+ in CO2RR on Cu surface. A monotonically decreasing CO2 activation barrier is obtained from Li+ to Cs+, which is attributed to the different coordination abilities of M+ with *CO2. Furthermore, we show that the competing hydrogen evolution reaction must be considered simultaneously to understand the crucial role of alkali metal cations in CO2RR on Cu surfaces, where H+ is repelled from the interface and constrained by M+. Our results provide significant insights into the design of electrochemical environments and highlight the importance of explicitly including the solvation and competing reactions in theoretical simulations of CO2RR.

A Sulfur‐Doped Copper Catalyst with Efficient Electrocatalytic Formate Generation during the Electrochemical Carbon Dioxide Reduction Reaction

AbstractCatalysts involving post‐transition metals have shown almost invincible performance on generating formate in electrochemical CO2 reduction reaction (CO2RR). Conversely, Cu without post‐transition metals has struggled to achieve comparable activity. In this study, a sulfur (S)‐doped‐copper (Cu)‐based catalyst is developed, exhibiting excellent performance in formate generation with a maximum Faradaic efficiency of 92 % and a partial current density of 321 mA cm−2. Ex situ structural elucidations reveal the presence of abundant grain boundaries and high retention of S−S bonds from the covellite phase during CO2RR. Furthermore, thermodynamic calculations demonstrate that S−S bonds can moderate the binding energies with various intermediates, further improving the activity of the formate pathway. This work is significant in modifying a low‐cost catalyst (Cu) with a non‐metallic element (S) to achieve comparable performance to mainstream catalysts for formate generation in industrial grade.

Synthesis and Electrocatalytic Applications of Layer-Structured Metal Chalcogenides Composites.

Featured with the attractive properties such as large surface area, unique atomic layer thickness, excellent electronic conductivity, and superior catalytic activity, layered metal chalcogenides (LMCs) have received considerable research attention in electrocatalytic applications. In this review, the approaches developed to synthesize LMCs-based electrocatalysts are summarized. Recent progress in LMCs-based composites for electrochemical energy conversion applications including oxygen reduction reaction, carbon dioxide reduction reaction, oxygen evolution reaction, hydrogen evolution reaction, overall water splitting, and nitrogen reduction reaction is reviewed, and the potential opportunities and practical obstacles for the development of LMCs-based composites as high-performing active substances for electrocatalytic applications are also discussed. This review may provide an inspiring guidance for developing high-performance LMCs for electrochemical energy conversion applications.

CO2 electroreduction on two-dimensional transition metal 1,2,3,4,5,6,7,8,9,10,11,12-perthiolated coronene frameworks: a theoretical investigation

Developing highly efficient catalysts for carbon dioxide reduction reaction (CO2RR) is significant in producing useful chemicals and alleviating environmental pollution. Herein, a series of two-dimensional TM-PTC (TM = Sc-Zn, PTC = 1,2,3,4,5,6,7,8,9,10,11,12-perthiolated coronene) frameworks as CO2RR electrocatalysts are investigated based on the density functional method. The calculated results showed that the main product is CH4 for TM-PTC (TM = Sc-Mn). However, these catalysts can be poisoned by water molecules due to its strong adsorption on the catalyst surface. To solve the problem, we modified these catalysts by adding axial oxygen (TM-O-PTC). Our study showed that TM-O-PTC (TM = V, Cr) are good catalysts for CO2RR to produce CH4. We expected that this work could provide a useful strategy for developing high-performance CO2RR electrocatalysts.

Mechanism of electrocatalytic CO2 reduction reaction by borophene supported bimetallic catalysts

Bimetal atom catalysts (BACs) hold significant potential for various applications as a result of the synergistic interaction between adjacent metal atoms. This interaction leads to improved catalytic performance, while simultaneously maintaining high atomic efficiency and exceptional selectivity, similar to single atom catalysts (SACs). Bimetallic site catalysts (M2β12) supported by β12-borophene were developed as catalysts for electrocatalytic carbon dioxide reduction reaction (CO2RR). The research on density functional theory (DFT) demonstrates that M2β12 exhibits exceptional stability, conductivity, and catalytic activity. Investigating the most efficient reaction pathway for CO2RR by analyzing the Gibbs free energy (ΔG) during potential determining steps (PDS) and choosing a catalyst with outstanding catalytic performance for CO2RR. The overpotential required for Fe2β12 and Ag2β12 to generate CO is merely 0.05 V. This implies that the conversion of CO2 to CO can be accomplished with minimal additional voltage. The overpotential values for Cu2β12 and Ag2β12 during the formation of HCOOH were merely 0.001 and 0.07 V, respectively. Furthermore, the Rh2β12 catalyst exhibits a relatively low overpotential of 0.51 V for CH3OH and 0.65 V for CH4. The Fe2β12 produces C2H4 through the *CO-*CO pathway, while Ag2β12 generates CH3CH2OH via the *CO-*CHO coupling pathway, with remarkably low overpotentials of 0.84 and 0.60 V, respectively. The study provides valuable insights for the systematic design and screening of electrocatalysts for CO2RR that exhibit exceptional catalytic performance and selectivity.

Influence of Environmental Conditions on Electrocatalytic CO2 Reduction

AbstractIn order to address the greenhouse effect and achieve the artificial carbon cycle, the electrocatalytic reduction reactions offer an effective approach for converting carbon dioxide (CO2) into valuable chemicals. In addition to the rational design of catalyst structure to improve the high selective conversion of CO2, exploring the influence of environmental conditions on the reaction path and product types is one of the keys to realizing the high selective conversion of CO2. In this review, we illustrate the important influence of changes in environmental conditions on the effectiveness of electrocatalytic carbon dioxide reduction reaction (CO2RR) technology from the design of the reactor, the selection of the electrolyte, and the setting of the reaction conditions (pressure, temperature, etc.). Through in‐depth understanding and optimization of these factors, the efficiency and selectivity of the CO2RR can be further improved to promote the development of CO2 conversion technology.

Design of highly selective and stable CsPbI3 perovskite catalyst for photocatalytic reduction of CO2 to C1 products

Finding efficient photocatalytic carbon dioxide reduction catalysts is one of the core issues in addressing global climate change. Herein, the pristine CsPbI3 perovskite and doped CsPbI3 perovskite were evaluated in carbon dioxide reduction reaction (CO2RR) to C1 products by using density functional theory. Free energy testing and electronic structure analysis methods have shown that doped CsPbI3 exhibits more effective catalytic performance, higher selectivity, and stability than undoped CsPbI3. Additionally, it is discovered that CsPbI3 (100) and (110) crystal surfaces have varied product selectivity. The photo-catalytic effectiveness is increased by the narrower band gap of Bi and Sn doped CsPbI3, which broadens the absorption spectrum of visible light and makes electron transport easier. The calculation results indicate that Bi doped CsPbI3 (100) and CsPbI3 (110) crystal faces exhibit good selectivity towards CH4, with free energy barriers as low as 0.55 eV and 0.58 eV, respectively. Sn doped CsPbI3 (100) and CsPbI3 (110) crystal planes exhibit good selectivity for HCOOH and CH3OH, respectively. The results indicate that the Bi and Sn doped CsPbI3 perovskite catalyst can further improve the CO2 photocatalytic activity and high selectivity for C1 products, making it a suitable substrate material for high-performance CO2RR.

Regulating CHO* intermediate pathway towards the significant acceleration of photocatalytic CO2 reduction to CH4 through rGO-coated ultrafine Pd nanoparticles

Tailoring catalytic reaction pathways by using reduced graphene oxide (rGO) to tune the electron-hole separation channels in the active sites of noble metals for achieving ideal yield and selectivity in photocatalytic CO2 reduction of hydrocarbon fuels remains a challenge. Herein, ternary catalyst of rGO-coated SnO2-supported noble metal Pd nanoparticles (Pd4/SnO2@rGO) has been prepared by coassembly between negatively charged graphene oxide and positively charged Pd nanoparticles. By coating with ultrathin rGO, the selectivity can be shifted from CO (44.69 % for Pd4/SnO2) toward CH4 as the prevalent species, in which the Pd nanoparticles acted as catalytic sites and electron capture sites. The rGO coating reduced the recombination of the photogenerated carriers as well as optimized the band gap and reduction potential of the catalyst. The in situ spectroscopic tests and density functional theory calculations revealed that CO2 adsorbed on Pd nanoparticles selectively formed dominant low-energy CHO* intermediates because of the generation of HCOOH* intermediates, thus providing a unique reaction pathway for the reduction of CO2 to CH4. Therefore, under sunlight irradiation, the CH4 selectivity of the catalyst is enhanced to 94.1 % with a production rate of up to 77.8 μmol·g−1·h−1. This work demonstrated the prospect to tune the electronic structure of Pd using rGO, which provided a strategy for enhancing the carbon dioxide reduction reaction and selectively obtaining CH4 products in photocatalytic systems.

Ultra‐Fast Pulsed Discharge Preparation of Coordinatively Unsaturated Asymmetric Copper Single‐Atom Catalysts for CO2 Reduction

AbstractSingle‐atom catalysts possess great potential for applications in electrochemical carbon dioxide reduction reactions. Recently, the fast and low‐cost preparation of highly efficient single‐atom catalysts remains a challenge. Herein, a high‐density current generated by pulsed discharge is employed for the formation of graphene aerogel anchored Cu single atom catalysts perfectly. The Cu atoms decomposed by Cu(NO3)2•xH2O are fixed on graphene under the local transient high temperature and intense electromagnetic field. The activity and selectivity of formic acid are correlated with the coordinatively unsaturated Cu─N1O1 moieties, reaching an optimal Faradaic efficiency (93.7%) at −0.9 V versus a reversible hydrogen electrode (RHE). In situ characterizations reveal that the asymmetric Cu─N/O structure in a pinched state displays better catalytic activity in CO2RR. Density functional theory results indicate that the Cu─N1O1 sites regulate the adsorption configuration of intermediates and lower the energy barrier for the hydrogenation of *OCHO species, thereby promoting CO2‐to‐HCOOH conversion.

Guanine-derived carbon nanosheet encapsulated Ni nanoparticles for efficient CO2 electroreduction.

Developing novel electrocatalysts for achieving high selectivity and faradaic efficiency in the carbon dioxide reduction reaction (CO2RR) poses a major challenge. In this study, a catalyst featuring a nitrogen-doped carbon shell-coated Ni nanoparticle structure is designed for efficient carbon dioxide (CO2) electroreduction to carbon monoxide (CO). The optimal Ni@NC-1000 catalyst exhibits remarkable CO faradaic efficiency (FECO) values exceeding 90% across a broad potential range of -0.55 to -0.9 V (vs. RHE), and attains the maximum FECO of 95.6% at -0.75 V (vs. RHE) in 0.5 M NaHCO3. This catalyst exhibits sustained carbon dioxide electroreduction activity with negligible decay after continuous electrolysis for 20 h. More encouragingly, a substantial current density of 200.3 mA cm-2 is achieved in a flow cell at -0.9 V (vs. RHE), reaching an industrial-level current density. In situ Fourier transform infrared spectroscopy and theoretical calculations demonstrate that its excellent catalytic performance is attributed to highly active pyrrolic nitrogen sites, promoting CO2 activation and significantly reducing the energy barrier for generating *COOH. To a considerable extent, this work presents an effective strategy for developing high-efficiency catalysts for electrochemical CO2 reduction across a wide potential window.

Unveiling the magnetic ordering effect in La-doped Ti3C2O2 MXenes on electrocatalytic CO2 reduction

In the pursuit of sustainable energy solutions, the carbon dioxide reduction reaction (CO2RR) holds immense promise for converting CO2 into valuable chemicals and fuels.

Redox-active covalent organic nanosheets (CONs) as a metal-free electrocatalyst for selective CO2 electro-reduction to the liquid fuel methanol

In essence, the utilization of renewable energy in the carbon dioxide reduction reaction (CO2RR) holds the potential to transform carbon emissions into valuable chemicals, encompassing a range of hydrocarbons and alcohols.

Rare earth oxide based electrocatalysts: synthesis, properties and applications.

As an important strategic resource, rare earths (REs) constitute 17 elements in the periodic table, namely 15 lanthanides (Ln) (La-Lu, atomic numbers from 57 to 71), scandium (Sc, atomic number 21) and yttrium (Y, atomic number 39). In the field of catalysis, the localization and incomplete filling of 4f electrons endow REs with unique physical and chemical properties, including rich electronic energy level structures, variable coordination numbers, etc., making them have great potential in electrocatalysis. Among various RE catalytic materials, rare earth oxide (REO)-based electrocatalysts exhibit excellent performances in electrocatalytic reactions due to their simple preparation process and strong structural variability. At the same time, the electronic orbital structure of REs exhibits excellent electron transfer ability, which can reduce the band gap and energy barrier values of rate-determining steps, further accelerating the electron transfer in the electrocatalytic reaction process; however, there is a lack of systematic review of recent advances in REO-based electrocatalysis. This review systematically summarizes the synthesis, properties and applications of REO-based nanocatalysts and discusses their applications in electrocatalysis in detail. It includes the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), hydrogen oxidation reaction (HOR), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), methanol oxidation reaction (MOR), nitrogen reduction reaction (NRR) and other electrocatalytic reactions and further discusses the catalytic mechanism of REs in the above reactions. This review provides a timely and comprehensive summary of the current progress in the application of RE-based nanomaterials in electrocatalytic reactions and provides reasonable prospects for future electrocatalytic applications of REO-based materials.

Acidic CO2 electroreduction for high CO2 utilization: catalysts, electrodes, and electrolyzers.

The electrochemical carbon dioxide (CO2) reduction reaction (CO2RR) is considered a promising technology for converting atmospheric CO2 into value-added compounds by utilizing renewable energy. The CO2RR has developed in various ways over the past few decades, including product selectivity, current density, and catalytic stability. However, its commercialization is still unsuitable in terms of economic feasibility. One of the major challenges in its commercialization is the low single-pass conversion efficiency (SPCE) of CO2, which is primarily caused by the formation of carbonate (CO32-) in neutral and alkaline electrolytes. Notably, the majority of CO2RRs take place in such media, necessitating significant energy input for CO2 regeneration. Therefore, performing the CO2RR under conditions that minimize CO32- formation to suppress reactant and electrolyte ion loss is regarded an optimal strategy for practical applications. Here, we introduce the recent progress and perspectives in the electrochemical CO2RR in acidic electrolytes, which receives great attention because of the inhibition of CO32- formation. This includes the categories of nanoscale catalytic design, microscale microenvironmental effects, and bulk scale applications in electrolyzers for zero carbon loss reactions. Additionally, we offer insights into the issue of limited catalytic durability, a notable drawback under acidic conditions and propose guidelines for further development of the acidic CO2RR.

Unveiling the key role of excited-state hydrogen bonding in homogeneous photocatalytic CO2 reduction

In this paper, we investigated the role of excited-state hydrogen bonding in the photocatalytic carbon dioxide reduction reaction (CO2RR) utilizing Rose Bengal as a catalyst, through a combined experimental and theoretical approach.