The economic viability of the electrochemical CO2 reduction reaction relies not only on efficient catalytic performance but also on the scalability and cost-efficiency of catalyst production. Herein, a rapid and scalable sonochemical synthesis of AgCl nanocubes (AgCl NCs), featuring efficient manufacturability, high CO selectivity, and long-term stability is reported. In a membrane electrode assembly, AgCl NC maintained exceptionally high CO Faradaic efficiencies (>95%) during 200 h of continuous operation. Techno-economic analysis (TEA) revealed that the outstanding performance of AgCl NC, coupled with its cost- and time-efficient synthesis, significantly lowered the levelized catalyst cost by 40% and the CO production cost by nearly 50% relative to conventional Ag nanoparticle systems. By linking catalyst production directly to system-level TEA outcomes, this study highlights manufacturability as a key yet often overlooked criterion in catalyst design and positions AgCl NC as a promising platform for industrial-scale application.

Paired electrolysis of CO2 and biomass-derived alcohols, such as 5‑hydroxymethylfurfural (HMF) and glycerol, offers a sustainable approach for co-producing valuable chemicals, but suffers from poor cathode-anode compatibility and limited economic feasibility. Herein, we show that replacing CO2 with carbon monoxide (CO) and adopting a catholyte-layer electrolyzer design jointly enhance the operational stability of alcohol-paired electrolysis by preventing HCO3 - formation and suppressing inter‑electrode mass exchange. Within this platform, HMF oxidation is identified as the optimal anodic partner compared with glycerol oxidation, because it exhibits negligible product crossover and the oxidation kinetics of its intermediates consistently outpace those of the oxygen evolution reaction. Consequently, the paired electrolysis of CO and HMF in a membrane-electrode assembly electrolyzer incorporating a catholyte-layer enabled efficient and stable co‑production of ethylene and 2,5‑furandicarboxylic acid (FDCA), both key plastic monomers derived from CO2 and biomass, respectively. Techno-economic and environmental assessment indicate that the CO-HMF pairing outperforms all tested combination of CO2 or CO-HMF or glycerol and approaches the production cost and carbon emission to petroleum-derived terephthalic acid. These results demonstrate CO electrolysis coupled with HMF oxidation as a cost-effective and climate-conscious strategy for sustainable chemical production.

Recent studies suggest that the local acidic microenvironment and dissolution caused by organic crossover are critical factors to consider for the viability of anode catalysts in zero-gap CO2 electrolyzer. Despite their cost-effectiveness, the application of transition metal oxide catalysts for the anode in CO2 electrolyzer has been limited due to their dissolution in locally acidic environments. In this work, we investigate the feasibility of transition metal oxides as effective anode materials for zero-gap CO2 electrolysis by using acidic stable CoMn spinel oxide. The CoMn spinel oxide catalyst exhibited promising durability in the local acidic microenvironment. However, accelerated dissolution was observed in the presence of ethanol. We propose that the participation of lattice oxygen during the electro-oxidation of unhydrated aldehydes induces the collapse of the oxide matrix, thereby leading to the rapid dissolution of transition metal oxides. Our findings highlight the potential of transition metal oxides as viable anode materials for CO2 electrolyzer targeting C1 product.

Among advanced carbon capture and utilization strategies, the reactive capture and conversion (RCC) strategy offers significant advantages by directly converting CO2 in its captured state, eliminating the need for high-purity CO2 and separation processes. Herein, we developed an electrochemical RCC system that efficiently converts the captured CO2 into high-purity formic acid by integrating CO2 capture, electrochemical conversion, and formic acid purification. Triethylamine (TREA) was selected as the CO2 absorbent because it captures CO2 as bicarbonate. The TREA-captured CO2 was converted to formate with a 60% Faradaic efficiency and a 94% CO2-to-formate yield through an electrochemical RCC system equipped with a Sn-Cu catalyst in a membrane electrode assembly electrolyzer. Purification was completed via a two-step process involving amine exchange for TREA regeneration and distillation. In situ Raman spectroscopy elucidated the key intermediates and demonstrated the roles of the catalyst and CO2 absorbent. Techno-economic analysis and life cycle analysis highlighted this system’s promising profitability and environmental sustainability.

Electrochemical CO 2 reduction (CO 2 RR) is a promising strategy for converting CO 2 into value-added chemicals. Beyond the conventional use of purified CO 2 , direct flue gas utilization offers a pathway to improve...

Electrocatalysts often undergo dynamic phase transitions during electrochemical operation, which introduce structural and chemical complexities that obscure the fundamental origins of their catalytic performance. Oxide-derived Cu (OD-Cu), produced by the electrochemical reduction of Cu oxide, exemplifies this challenge and continues to prompt debate regarding the nature of its high activity in CO2 electrolysis. Here, using cryogenic atom probe tomography, we show the formation of nanoscale Na+-containing microstructures within OD-Cu, originating from phase transitions of Cu oxide in a NaHCO3 electrolyte. Comparative studies with Na+-free OD-Cu and pulsed electrolysis identify a strong correlation between Na+ impurity incorporation and enhanced CO2 electrolysis activity. Complementary in situ Raman spectroscopy studies further confirm that these extrinsic impurities stabilize labile yet catalytically active Cu+ species. Overall, our findings elucidate the pivotal role of Na+ impurities and provide mechanistic insights to guide the rational design of synthetic and operational strategies for more efficient CO2 valorization.

This study investigates how the molecular structure of imidazolium ionomers with linear alkyl side chains (CnH2n+1 where n = 1, 4, 10, 16) modulates interfacial microenvironments in the Ag-catalyzed CO2 reduction reaction (CO2RR). Variations in side chain length and molecular weight establish structure-performance relationships that link hydrophobicity and ion transport to activity and selectivity. Longer side chains suppress hydrogen evolution and enhance the CO2RR, with the n-hexadecyl ionomer achieving the highest Faradaic efficiency for the CO2RR of 90.1% in a two-compartment cell. Incorporation of this ionomer in a cation-exchange membrane-based membrane electrode assembly achieves selective CO production with a partial current density exceeding 100 mA cm(-2), outperforming a commercial benchmark. Controlled studies under lean and acidic electrolytes reveal that the ionomer maintains local alkaline environments by restricting the interfacial water and proton transport. These findings provide molecular-level insights into ionomer function and design principles for selective CO2RR in practical electrolyzers.

Polymeric ionomers near the catalyst surface of CO2 reduction reaction (CO2RR) electrodes affect their efficiency; however, their multifaceted properties complicate structure-activity relationship elucidation. Here, we synthesized polycarbazole-based anion-exchange (QPC) ionomers bearing varying functionalized side chains to explore this relationship. Comprehensive analysis in physicochemical properties, electrochemical activity, and operando ATR-SEIRAS revealed that functional group modification significantly influenced the intrinsic ionomer properties, thereby affecting the Ag catalyst properties, microenvironments of interfacial water structures, and reaction kinetics of the protonation step for CO2RR and the hydrogen evolution reaction (HER). Notably, the QPC-trimethyl phosphonium (TMP) ionomer induced favorable interfacial water structures, having a high proportion of strong H-bonded water with low Stark tuning slopes, which inhibit HER and promote CO2RR. A high CO Faradaic efficiency (>90%) was maintained using QPC-TMP in a membrane electrode assembly, even under varying CO2 concentrations (100-15%) and elevated temperatures (28-72 degrees C). These findings suggest that the catalytic environment can be optimized by fine-tuning the ionomer structure, contributing to the advancement of high-performance CO2RR ionomers.

The rapid accumulation of atmospheric carbon dioxide (CO 2 ) is a critical global challenge that demands innovative solutions. Carbon dioxide capture and utilization (CCU) has emerged as a promising strategy to mitigate CO 2 emission by converting it into value-added products. Among various CCU approaches, reactive capture and conversion (RCC) presents a compelling advantage by integrating CO 2 capture and electrochemical conversion in a single system. This developed system eliminates the need for high-purity CO 2 supply and complex product separation processes. This study introduces an electrochemical RCC system that efficiently converts CO 2 captured by triethylamine (TREA) into high-concentration formic acid. In our approach, TREA was employed as a CO 2 absorbent due to its ability to selectively capture CO 2 as bicarbonate. This captured CO 2 was directly converted into formic acid in an electrochemical system utilizing a Sn-Cu catalyst. The optimized Sn-Cu catalyst exhibited a Faradaic efficiency of 59.70% for formic acid production, achieving an overall CO 2 -to-formate conversion yield of 94.09%. Furthermore, the system demonstrated excellent operational stability, maintaining consistent performance for up to 100 hours. The produced formate was subsequently purified into high-concentration formic acid using a two-column separation process consisting of amine exchange for TREA regeneration and distillation for formic acid purification. In situ Raman spectroscopy was conducted to gain mechanistic insights into the key reaction intermediates. To our knowledge, this is the first time in situ Raman was conducted in direct capture and utilization of CO 2 with amine solution. The findings revealed that *CO 2 - and *OCHO species play critical roles in facilitating the electrochemical CO 2 reduction of TREA-captured CO 2 into formate. Additionally, by optimizing the ratio of Sn and Cu, the CO 2 absorbent was found to enhance the adsorption and activation of CO 2 intermediates. Beyond its electrochemical performance, the feasibility and sustainability of the proposed RCC system were assessed through a comprehensive techno-economic analysis (TEA) and life cycle assessment (LCA). The TEA indicated that this approach presents a cost-competitive alternative to conventional formic acid production methods, while the LCA demonstrated its potential for significant reductions in carbon footprint compared to state-of-the-art electrochemical CO 2 -to-formic acid conversion systems. These analyses highlight the economic viability and environmental benefits of integrating direct CO 2 capture and electrochemical conversion. This study underscores the potential of electrochemical RCC as a scalable and sustainable approach for CO 2 utilization, offering a novel pathway for high-concentration formic acid production. By integrating CO 2 capture, electrochemical conversion, and product purification, this system represents a significant step toward advancing next-generation CCU technology. The findings of this study contribute to the broader effort of developing innovative CO 2 conversion strategies that align with global sustainability goals. Figure 1

Catalyst degradation is a significant challenge for the commercialization of the electrochemical reduction of CO2, as it decreases activity and selectivity. However, the high experimental cost of catalyst characterization hinders the generation of sufficient and valuable information regarding catalyst degradation. Recently, machine learning (ML) models have exhibited high potential to replace costly processes, but their low interpretability makes their application challenging. Herein, we introduce an interpretable ML framework that accurately projects the catalyst status using simple linear sweep voltammetry (LSV) within subseconds while providing insights into the origin of catalyst degradation. A convolutional neural network trained on experimentally collected 5196 LSV results achieved superior performance in total current and Faradaic efficiency predictions. The ML framework demonstrates an impressive accuracy of mean absolute error below 0.5% in predicting the Faradaic efficiency of various products, irrespective of the operating conditions and catalyst types. The prediction mechanism learnt by the model was interpreted via explainable artificial intelligence (XAI), and critical degradation factors were identified. We performed catalyst surface analyses at milestone points to verify the XAI interpretation and demonstrate the reliability of the proposed framework. This approach can potentially be applied to a wide range of electrochemistry involving catalytic process, battery degradation, and chemical process monitoring, suggesting that it offers a viable means of rapidly and reliably monitoring performance.

Methanol synthesis via CO 2 hydrogenation is increasingly recognized as a pivotal strategy in CO 2 utilization, addressing both environmental concerns and the demand for sustainable chemical production. However, the exothermic nature of methanol synthesis often leads to thermal management issues in reactors, particularly near the inlet. This study proposes an optimized three‐stage reactor system with a distinctive approach to catalyst distribution. Each reactor is divided into two zones, culminating in six zones with varied catalyst loadings, specifically designed to alleviate hot spots. The advanced modeling platform developed in this study significantly reduces the computational intensity typically required in such processes. This platform integrates a process simulator with computational fluid dynamics (CFD) modeling, allowing for efficient computation of reaction rates and heat release as well as detailed temperature profiles in both axial and radial directions. Using an efficient Gaussian process Bayesian optimization (GPBO) algorithm, we optimized the catalyst loading with the minimum number of iterations. Our findings indicate a significant decrease in temperature variances in reactors of various sizes: 67.5% in a 2‐inch tube reactor, 55.4% in a 1‐inch reactor, and 67.3% in a 3/8‐inch reactor, when compared to conventional methanol reactor. The maximum temperature differences were notably reduced by up to 15.7 K in the axial direction for 3/8‐inch tubes and up to 2.5 K in the radial direction for 2‐inch tubes. Additionally, the study provides insights into the promotional effects of CO. This platform not only optimizes reactor performance but also provides a substantial advancement in the computational modeling of methanol synthesis from CO 2 .

Methanol synthesis via CO2 hydrogenation is increasingly recognized as a pivotal strategy in CO2 utilization, addressing both environmental concerns and the demand for sustainable chemical production. However, the exothermic nature of methanol synthesis often leads to thermal management issues in reactors, particularly near the inlet. This study proposes an optimized three-stage reactor system with a distinctive approach to catalyst distribution. Each reactor is divided into two zones, culminating in six zones with varied catalyst loadings, specifically designed to alleviate hot spots. The advanced modeling platform developed in this study significantly reduces the computational intensity typically required in such processes. This platform integrates a process simulator with computational fluid dynamics (CFD) modeling, allowing for efficient computation of reaction rates and heat release as well as detailed temperature profiles in both axial and radial directions. Using an efficient Gaussian process Bayesian optimization (GPBO) algorithm, we optimized the catalyst loading with the minimum number of iterations. Our findings indicate a significant decrease in temperature variances in reactors of various sizes: 67.5% in a 2-inch tube reactor, 55.4% in a 1-inch reactor, and 67.3% in a 3/8-inch reactor, when compared to conventional methanol reactor. The maximum temperature differences were notably reduced by up to 15.7 K in the axial direction for 3/8-inch tubes and up to 2.5 K in the radial direction for 2-inch tubes. Additionally, the study provides insights into the promotional effects of CO. This platform not only optimizes reactor performance but also provides a substantial advancement in the computational modeling of methanol synthesis from CO2.

Electrocatalytic hydrodeoxygenation (EHDO) is a promising approach for upgrading biomass-derived bio-oils to sustainable fuels without the use of high-pressure hydrogen gas and elevated temperatures. However, direct EHDO for realistic hydrophobic lignin-based oil production remains challenging. Herein, we discuss the molecular dynamics that govern the EHDO of lignin bio-oil over Pt/C in an acidic electrolyte added with 2-propanol or a surfactant. Excellent conversion (98.1%) and a high yield (79.0%) of hydrogenated products, including 40.5% propyl-cyclohexane, are achieved under ambient temperature and pressure. Experimental results and various investigations on molecular dynamics suggest that EHDO occurs at the water-solvent-catalyst three-phase boundary. Proton transfer significantly influences the current density of EHDO. Factors such as cluster size and vector of lignin-based oil to electrode govern the selectivity and Faradaic efficiency of EHDO. This work advances the understanding of dynamics for EHDO and suggests governing factors to improve it.

The tandem catalyst configuration has emerged as an effective strategy for enhancing the electrochemical conversion of CO2 into multicarbon (C2+) products by incorporating a CO-producing layer with a Cu catalyst. While numerous catalyst combinations have been explored to optimize performance, the role of binders within the catalytic layers of such tandem structures has been underappreciated, despite their significant influence on the microenvironment, thereby markedly affecting product selectivity. In this study, a tandem electrode comprising a CO-producing Ag layer atop a Cu layer was fabricated and its CO2 conversion performance was evaluated, focusing on the impact of binder wettability on C2+ production. Hydrophobic Cu layers outperformed their hydrophilic counterparts, exhibiting higher C2+ conversion rates and current densities. Notably, the C2+/CO ratios of the hydrophobic Cu-based electrodes varied significantly depending on the binder wettability of the CO-producing layer. The optimal configuration was found to be a hydrophilic CO-producing layer paired with a hydrophobic Cu layer, affording the highest C2+ partial current density of 220 mA cm–2. The variation in the C2+/CO ratio was attributed to differences in the water accessibility, primary proton source, and CO utilization within the Cu layer, as revealed by controlled modifications of the tandem electrode microenvironment. These findings highlight the pivotal role of binder wettability in optimizing CO2-to-C2+ conversion, offering a viable strategy for enhancing the CO2 reduction reaction performance.

Coupling CO 2 electrolysis with biomass oxidation in a single reactor enhances the economic viability of electrosynthesis. However, the use of highly basic anolyte for alcohol oxidation poses significant challenges, reducing operational lifespans. Herein, a solution is presented using triethylamine (TEA) as both a CO 2 ‐capturing agent and pH buffer for the oxidation of 5‐hydroxymethylfurfural (HMF), replacing traditional hydroxide salts. A tailored triethylamine‐carbonate solution mitigates the challenges posed by basic electrolytes and enhances oxidation reactivity of HMF. Furthermore, the coating of an anion‐conducting ionomer on the anode surface improves pH buffering and improves reactant adsorption. These advancements enable stable HMF oxidation without anolyte refreshment, even as the pH approaches neutral, allowing for the co‐production of synthetic gas and 2,5‐furan dicarboxylic acid (FDCA), a key plastic precursor, over 150 h in a membrane‐electrode assembly reactor. This finding demonstrates a viable pathway for integrating reactive carbon capture and oxidative conversion of biomass for electrosynthesis.

Electrochemical CO2 conversion (eCO2R) into value-added products presents a promising strategy for mitigating global warming. However, this technology faces a significant challenge: supplying high-purity CO2 and purifying the product requires a substantial amount of thermal energy, as most systems typically use highly concentrated CO2 as a reactant. Herein, we suggested a new concept of system that bypasses energy-intensive conditioning by directly converting amine-captured CO2 into highly concentrated syngas and formic acid, using a novel amine-type CO2 absorbent, triethylamine (TREA). Our experiments show that the CO2 absorption rate (>84%) of TREA is comparable to conventional alkanolamine, with the majority of CO2 captured as bicarbonate‒a form preferred for direct electrochemical use due to its easy desorption. To efficiently convert TREA-captured CO2 into C1 products, we optimized the system configuration based on the membrane electrode assembly (MEA) electrolyzer, and bipolar membrane applied MEA emerged as optimal. This system requires different mass transport approaches since the reactant is delivered in liquid phase, not as gaseous CO2. We developed a hydrophilic coral-Ag/carbon electrode that provides CO production active sites and facilitates interaction with TREA-captured CO2. This electrode achieved 70% CO Faradaic efficiency (FE) and 30% H2 FE at 20 mA cm-2, with selectivity varying by current density in the TREA-captured CO2 conversion system. Moreover, we discovered that high-purity syngas production is possible due to the re-capturing of unreacted CO2 in TREA, eliminating the need for post-production purification. Based on the experimental results and rigorous process modeling, we reveal that this system can produce high pressure syngas at a reasonable cost with negligible CO2 emissions. To enhance system feasibility, we also developed TREA-captured CO2 conversion to produce highly concentrated formic acid, which exists primarily as formate (HCOO-) in aqueous solutions. In conventional eCO2R systems, converting formate to formic acid involves energy- and cost-intensive steps, including acidification and purification to separate formic acid from electrolyte precursors. Our method directly converts TREA-captured CO2 to formate using a Sn-Cu alloy catalyst, simplifying the purification of formate to formic acid in two-steps. Protonated TREA chemically stabilizes formate through ionic interaction, allowing for the stabilization of highly concentrated formate in the TREA solution. The Sn-Cu alloy achieved maximum 60% of formate FE at 50 mA cm-2 with 28% of H2 FE and 14% of CO, with selectivity varying by current density. During long-term operation at a constant current density condition of 100 mA cm-2, the Sn-Cu alloy produced 2.6 M formate in the TREA-captured CO2 system, recording 94% conversion captured CO2. The purification process of formate into formic acid does not require high temperatures (not exceeding 150°C) or harsh chemicals by utilizing amine switching method, highlighting our system's environmental and practical benefits. These demonstrate the practical feasibility and minimal global warming impact of the TREA-captured CO2 conversion system, compared to other advanced Carbon Capture and Utilization strategies. Figure 1

A comprehensive review of direct captured CO2 electro-conversion technology, a promising Carbon Capture and Utilization (CCU) technology that can achieve both techno-economic and environmental viability.

AbstractThis study presents the impact of the side chains in 1‐n‐alkylimidazolium ionomers with varying side chain lengths (CnH2n+1 where n = 1, 4, 10, 16) on Cu‐catalyzed electrochemical CO2 reduction reaction (CO2RR). Longer side chains suppress the H2 and CH4 formation, with the n‐hexadecyl ionomer (n = 16) showing the greatest reduction in kinetics by up to 56.5% and 60.0%, respectively. On the other hand, C2H4 production demonstrates optimal Faradaic efficiency with the n‐decyl ionomer (n = 10), a substantial increase of 59.9% compared to its methyl analog (n = 1). Through a combination of density functional theory calculations and material characterization, it is revealed that the engineering of the side chains effectively modulates the thermodynamic stability of key intermediates, thus influencing the selectivity of both CO2RR and hydrogen evolution reaction. Moreover, ionomer engineering enables industrially relevant partial current density of –209.5 mA cm−2 and a Faradaic efficiency of 52.4% for C2H4 production at 3.95 V, even with a moderately active Cu catalyst, outperforming previous benchmarks and allowing for further improvement through catalyst engineering. This study underscores the critical role of ionomers in CO2RR, providing insights into their optimal design for sustainable chemical synthesis.

The relentless growth of plastic has emerged as a significant environmental and human health concern. Catalytic glycolysis of polyethylene terephthalate (PET) has proven to be an effective solution. This study investigated a series of M-BDC (M = Ni, Co, Cu, and Zn) metal -organic frameworks as catalysts for PET glycolysis. Zn-BDC exhibited the best experimental performance. Subsequently, the effects of operating conditions were optimized for the first time through a comprehensive investigation using a model based on deep neural networks (DNNs). The guidance of the DNN model resulted in a BHET selectivity as high as 0.95, outperforming most current heterogeneous catalysts for PET depolymerization. Furthermore, the apparent activation energy was also estimated by kinetic study. In addition, our designed system exhibits high durability after five consecutive runs, reflecting its promising escalation at the industrial level. Notably, the fabrication of the M-BDC framework can utilize the organic linker terephthalic acid (TPA) derived from the BHET monomer. By applying this strategy, we have achieved a significant advancement towards closed-loop PET recycling, contributing to a more comprehensive definition of sustainable development.

Ni phosphides and NiCo alloys are extensively explored for their remarkable efficiency in biomass alcohol oxidations, yet the underlying mechanisms remain inadequately understood. This study thoroughly elucidates the roles of Ni, Co, and P in improving the catalytic performance of Ni-Co-P catalysts for the electrochemical conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), a promising biomass-derived building block replacing terephthalic acid. Phosphorization of Ni results in the partial formation of Ni2P phase and significantly boosts the formation of the reactive NiOOH phase on the surface, which is the crucial catalytic phase for converting HMF into FDCA. The integration of Co into the heterojunction between Ni2P and NiOOH enhances the oxidation reactivity of 5-formyl-2-furancarboxylic acid (FFCA), a pivotal intermediate influencing FDCA productivity, by selectively stabilizing aldehydes, thereby promoting further oxidation rather than surface desorption. in situ/operando spectroscopic analyses consistently highlight the equal significance of the rapid generation of NiOOH and the robust adsorption of reactant molecules at the surface in achieving high catalytic performance. These insights into elemental contributions set a new standard for designing multi-component electrocatalysts for efficient biomass alcohol oxidation. Phosphorization of Ni and Co doping creates a NiOOH/Co-doped Ni2P heterojunction, facilitating HMF chemisorption and stabilizing aldehyde bonds, significantly enhancing FDCA productivity. Computational modeling outlines the entire HMF-to-FDCA conversion pathway, detailing the energetic changes driven by the heterojunction. In situ/operando Raman and IR analyses provide critical observations of changes in the catalyst surface and reactants during the reaction. image