Electrochemical CO2 Research Articles

Operando Investigation of the Origin of C─C Coupling in Electrochemical CO2 Reduction Upon Releasing Bonding Strength, Structural Ordering in Pd─Cu Catalyst

AbstractIt is widely established that the electroreduction of carbon dioxide on a copper surface yields a spectrum of alcohols and hydrocarbons. But the selectivity of Cu toward a certain product is extremely poor as it forms a variety of reduced products concurrently. Controlling selectivity and overall performance depends on the modification of the Cu site and local environment. This study depicts how the product selectivity can be switched from C1 to C2 and multicarbon products by systematic incorporation of secondary metal (Pd) into the Cu lattice. Upon releasing the structural ordering from intermetallic to alloy and then to bimetallic, a systematic enhancement on the formation of C2 products from CO2 has been observed. Real‐time in situ X‐ray absorption spectroscopy (XAS) study showed the potential dependent evolution of Pd─Cu and Cu─Cu bonds in different Pd‐Cu‐based catalysts. The detailed analysis of in situ IR and Raman also determined the adsorbed intermediate species and helped to identify the mechanism. Computational studies show the feasibility of multicarbon product formation on bimetallic catalysts compared to alloy and intermetallic catalysts. The current density and the activity of the CO2 electroreduction have been enhanced by the utilization of the flow cell in the gas diffusion electrode configuration.

Rotating cylinder electrode in reactive CO2 capture: Identifying active C species via transport, VLE models and kinetics

AbstractThis article explores technical challenges and potential methodologies for understanding electrochemical Reactive CO Capture (RCC) mechanisms. RCC offers potential energy cost advantages by directly converting captured CO into fuels and chemicals, unlike traditional carbon capture and utilization (CCU) processes that require sequential capture, concentration, and compression. However, direct conversion of captured CO introduces complexity due to additional equilibrium buffer reactions, making it challenging to identify active species for reduction in electrochemical studies. This article discusses methods to integrate transport, thermodynamics, and kinetics concepts to identify active carbon sources in RCC. Vapor‐Liquid Equilibrium (VLE) and transport models are validated against experimental results obtained in a gastight rotating cylinder electrode reactor and are shown as useful tools for studying RCC in heterogeneous electrocatalysts across different capture agents, solvents, and temperatures. This article establishes an experimental framework for advancing research in electrochemical RCC.

Synergistic modulation of valence state and oxygen vacancy induced by surface reconstruction of the CeO2/CuO catalyst toward enhanced electrochemical CO2 reduction

Synergistic modulation of valence state and oxygen vacancy induced by surface reconstruction of the CeO₂/CuO catalyst toward enhanced electrochemical CO₂ reduction

Origin of Metal–Support Interactions for Selective Electrochemical CO2 Reduction into C1 and C2+ Products

Origin of Metal–Support Interactions for Selective Electrochemical CO₂ Reduction into C₁ and C₂₊ Products

Deconvoluting XPS Spectra of La-Containing Perovskites from First-Principles.

Perovskite-based oxides are used in electrochemical CO2 and H2O reduction in electrochemical cells due to their compositional versatility, redox properties, and stability. However, limited knowledge exists on the mechanisms driving these processes. Toward this understanding, herein we probe the core level binding energy shifts of water-derived adspecies (H, O, OH, H2O) as well as the adsorption of CO2 on LaCoO3 and LaNiO3 and correlate the simulated peaks with experimental temperature-programmed X-ray photoelectron spectroscopy (TPXPS) results. We find that the strong adsorption of such chemical species can affect the antiferromagnetic ordering of LaNiO3. The adsorption of such adspecies is further quantified through Bader and differential charge analyses. We find that the higher O 1s core level binding energy peak for both LaCoO3 and LaNiO3 corresponds to adsorption of water-related species and CO2, while the lower energy peak is due to lattice oxygen. We further correlate these density functional theory-based core level O 1s binding energies with the TPXPS measurements to quantify the decrease of the O 1s contribution due to desorption of adsorbates and the apparent increase of the lattice oxygen (both bulk and surface) with temperature. Finally, we quantify the influence of adsorbates on the La 4d, Co 2p, and the Ni 3p core level binding energy shifts. This work demonstrates how theoretically generated XPS data can be utilized to predict species-specific binding energy shifts to assist in deconvolution of the experimental results.

Advancing electrochemical CO2 reduction with group 11 metal nanoclusters for renewable energy solutions

AbstractUnderstanding the intricate relationship between structure and properties is paramount in distinguishing nanocluster (NC) materials from their counterparts. Despite the progress in synthesizing new NCs, the sluggish exploration of their potential applications persists due to the difficulty in stabilizing these materials. However, recent investigations have unveiled their remarkable efficacy as catalysts in electrochemical CO2 reduction reactions, surpassing traditional materials. This discovery, addressing urgent global concerns, has quickly drawn significant attention to this field, leading to its rapid expansion. Hence, there is an urgent need to outline this research landscape and pinpoint effective strategies, marking a significant advancement. In this context, our endeavor is dedicated to offering researchers a thorough understanding of recently synthesized NC materials. We aim to elucidate their distinct structural architectures and associated properties essential for catalyst design. We envision that this systematic review will serve as a guiding beacon for future research endeavors in this burgeoning field.

Understanding the Temperature Effect on Carbon‐Carbon Coupling during CO2 and CO Electroreduction in Zero‐Gap Electrolyzers†

Comprehensive SummaryCu‐catalyzed electrochemical CO2 reduction reaction (CO2RR) and CO reduction reaction (CORR) are of great interest due to their potential to produce carbon‐neutral and value‐added multicarbon (C2+) chemicals. In practice, CO2RR and CORR are typically operated at industrially relevant current densities, making the process exothermal. Although the increased operation temperature is known to affect the performance of CO2RR and CORR, the relationship between temperatures and kinetic parameters was not clearly elaborated, particularly in zero‐gap reactors. In this study, we detail the effect of the temperature on Cu‐catalyzed CO2RR and CORR. Our electrochemical and operando spectroscopic studies show that high temperatures increase the activity of CO2RR to CO and CORR to C2H4 by enhancing the mass transfer of CO2 and CO. As the rates of these two processes are highly influenced by reactant diffusion, elevating the operating temperature results in high local CO2 and CO availability to accelerate product formation. Consequently, the *CO coverage in both cases increases at higher temperatures. However, under CO2RR conditions, *CO desorption is more favorable than carbon‐carbon (C—C) coupling thermodynamically at high temperatures, causing the reduction in the Faradaic efficiency (FE) of C2H4. In CORR, the high‐temperature‐augmented CO diffusion overcomes the unfavorable adsorption thermodynamics, increasing the probability of C—C coupling.

Synergistic Interaction between the Ni-Center and Glycine-Derived N-Doped Porous Carbon Material Boosts Electrochemical CO2 Reduction

Synergistic Interaction between the Ni-Center and Glycine-Derived N-Doped Porous Carbon Material Boosts Electrochemical CO₂ Reduction

Nitrogen‐Doped Carbon‐Encapsulated Nickel Nanoparticle Catalysts Using Covalent Organic Frameworks as Templates for Electrochemical CO2 Conversion

AbstractElectrochemical CO2 reduction (ECR) reactions, powered by cleaner energy, possess significant promise in mitigating CO2 emissions and achieving carbon recycling. Herein, Ni@N‐C electrocatalysts with encapsulated structures are prepared using covalent organic frameworks (COFs) as templates, where COF‐derived nitrogen‐doped carbon (N‐C) is utilized to wrap Ni nanoparticles. At the potential of −0.97 V vs. RHE, 2Ni@N‐C‐800 is characterized by a high current density (j = 24.2 mA cm‐2) and relatively high CO Faraday efficiency (FECO = 72%), reflecting its good catalytic activity. The ECR performance of 2Ni@N‐C‐800 is due to the cooperative interaction between Ni nanoparticles and the N‐C structure, which is inferred from control and poisoning measurements. This study provides a new idea for finding efficient and stable ECR catalysts.

Revealing Structural Evolution of Single Atom Catalysts during Electrochemical CO2 Reduction by in Situ X-ray Absorption Spectroscopy

Revealing Structural Evolution of Single Atom Catalysts during Electrochemical CO₂ Reduction by in Situ X-ray Absorption Spectroscopy

Revealing the Origin of Graphene Anchored Single Palladium Atom for Electrochemical CO2 Reduction to Syngas with Tunable CO/H2 Ratios

AbstractPd based catalysts are rare metal‐based catalyst to yield tunable CO/H2 ratios for Fischer‐Tropsch synthesis. How to achieve the co‐production of CO and H2 with as little Pd as possible is extremely meaningful for Cn industry. Recent experiment revealed single Pd atom anchored on graphene exhibits high activity for CO2 electroreduction to syngas, yet the origin of activity and controllable CO/H2 ratios, especially the exact Pd coordination structure, remains elusive. Here we employ grand‐canonical density functional theory to show that Pd−N1, rather than the commonly accepted Pd‐N4, serves as the active center, and the charge‐carrying capability is an effective descriptor. The site with more Pd−C coordination can better submerge in graphene‘s delocalized π electrons for higher charge‐carrying capacity to carry excess charges that occupy Pd 4dz2 orbital and promote electron injection. Importantly, the tunable CO/H2 ratio can be explained with difference in charge‐carrying capability of transition state for *COOH and *H2 formation. This work solves the puzzle of coordinating structure of Pd active site and demonstrates the important role of charge‐carrying capability in electrochemical process, which shall provide a reference for further exploration of efficient electrocatalysts.

Lowering *CO Affinity over Cu Nanoparticles for Enhanced Electrochemical CO 2 Conversion to Multicarbon Products at High Current Density

Lowering *CO Affinity over Cu Nanoparticles for Enhanced Electrochemical CO ₂ Conversion to Multicarbon Products at High Current Density

Electrochemical CO2 Reduction to Ethanol on Zn‐Coordinated Cu Sites Formed by Atmosphere‐Induced Surface Reconstruction

AbstractElectrochemical CO2 reduction reaction (CO2RR) to produce chemicals and fuels is a promising strategy to achieve carbon neutrality. However, due to the slow C─C coupling kinetics and the fact that C2H5OH and C2H4 products share the same *HCCOH intermediate, achieving high activity and selectivity for C2H5OH remains challenging. This paper describes an atmosphere‐induced reconstruction method to optimize the surface composition and coordination structure of the CuxZny bimetallic alloy catalysts for C2H5OH production. Specifically, the CuxZny alloy catalyst treated within CO atmosphere (CO‐CuxZny) enriches with low‐coordinated Cu sites, which are favorable for the adsorption of the *CO intermediates for promoted C2H5OH production. A C2+ Faradaic efficiency (FE) of 85.1% and a C2H5OH FE of 59.5% are achieved by the CO‐Cu84Zn16 at a current density of 300 mA cm−2. In‐situ spectroscopic studies and DFT calculations demonstrate that the enhanced *CO adsorption promotes the C─C coupling process. At the same time, the hydrogenation of *HCCOH is more favorable on CO‐Cu84Zn16 to inhibit the C2H4 pathway, thus enhancing the generation of C2H5OH. This study provides an effective strategy to regulate the selectivity of CO2RR through the control of the surface coordination environment of the active sites.

Synergy or Antagonism? Exploring the Interplay of SnO2 and an N-OMC Carbon Capture Medium for the Electrochemical CO2 Reduction toward Formate

Synergy or Antagonism? Exploring the Interplay of SnO₂ and an N-OMC Carbon Capture Medium for the Electrochemical CO₂ Reduction toward Formate

Designing Bi‐In2O3 Nanoflower Catalysts for Enhanced Performance of Electrochemical CO2 Reduction to Formate

AbstractElectrochemical CO2 reduction (ECO2RR) is capable of converting CO2 into a wide range of value‐added products under relatively mild conditions. Electrocatalyst with high selectivity and activity is crucial for high efficient ECO2RR. Herein, Bi‐In2O3 nanoflower catalysts with different metal ratios synthesized by wet chemical method are used for ECO2RR to produce formate. The results indicate that the hydrogen evolution activity of the Bi‐In2O3 catalysts during ECO2RR is suppressed at a low level and the activity and selectivity of formate production is related to the ratio of Bi to In content in the catalysts. The optimized Bi‐In2O3 catalyst with the ratio of Bi6In94 can achieve a high formate Faradaic efficiency (FEformate) over 80 % under a wide potential range from −0.7 V to −1.2 V vs. RHE, with the maximum value of 88.1 % at −0.7 V vs. RHE. Meanwhile, the highest formate partial current density reaches 47.7 mA cm−2 at −1.2 V vs. RHE and the current density and Faradaic efficiency remain stable during the 10 h stability test. The enhanced formate formation on Bi‐In2O3 NF can be attributed to the synergistic effect between Bi and In according to the characterizations of the Bi‐In2O3 NF.

Selective Electrochemical CO2 Reduction tuned by N Configuration on graphitic Shells of Nickel Particles

AbstractDespite of high conductivity and reducing ability, transition metal nanoparticles tend to aggregate and unavoidably impact the selectivity during the proton‐coupled reduction process of CO2RR. New strategy to regulate and utilize the electronic property of transition‐metal particles allows for effective tuning of eCO2RR activity. Through simple creation of N‐doped carbon shells surrounding Ni nanoparticles and controlling the amount and arrangement of the N atoms, successful and long‐lasting electrochemical reduction of CO2 was accomplished. The inherent HER activity was almost completely suppressed. It exhibited FECO above 90 % in a 500 mV potential window, with the optimal up to 96.5 % at −0.78 V vs RHE. In flow cell electrolysis, a current density of 289.4 mA/cm2 was achieved with Faradic efficiency of 96.4 % towards CO. The results of control experiments using different catalysts imply that electron transfer between Ni core and shells was significantly influenced by the property of N atoms. High content of graphitic nitrogen is crucial for the catalytic performance.

MOF-Derived N-Doped Carbon-Wrapped Ni Electrocatalyst for Highly Efficient Electrochemical CO2 Reduction to CO

MOF-Derived N-Doped Carbon-Wrapped Ni Electrocatalyst for Highly Efficient Electrochemical CO₂ Reduction to CO

Recent Progress on Boron-Doped Diamond Electrodes for Electrochemical CO2 Reduction: A Mini-review

Recent Progress on Boron-Doped Diamond Electrodes for Electrochemical CO₂ Reduction: A Mini-review

In Situ Fabrication of Cd Layer on Zn Foil Through Replacement Reaction for Electrochemical CO2 Reduction to CO

In Situ Fabrication of Cd Layer on Zn Foil Through Replacement Reaction for Electrochemical CO₂ Reduction to CO

Revisiting Factors Controlling the Electrochemical CO2 Reduction to CO and HCOOH on Transition Metals with Grand Canonical Density Functional Theory Calculations

Revisiting Factors Controlling the Electrochemical CO₂ Reduction to CO and HCOOH on Transition Metals with Grand Canonical Density Functional Theory Calculations