Directing the CO2 reduction reaction (CO2RR) toward ethanol offers a promising route to sustainable liquid fuels. However, achieving high ethanol selectivity under industrially relevant current densities still remains a major challenge. Here, we introduce trace sulfur doping via thiourea isomerization, which enables precise sulfur incorporation to weakly bind bridge-adsorbed OH species, thereby suppressing OH- adsorption on active sites and preventing their attack on defect sites. In situ Raman spectroscopy further reveals that suppressed OH- adsorption promotes the exposure of undercoordinated Cu active sites, enabling robust *CO atop-binding configurations to be sustained, particularly under strongly cathodic current densities. Additionally, the tailored surface microenvironment boosts *CO dimerization kinetics, and its synergistic interplay with *OH modulation channels the reaction pathway toward ethanol generation. Consequently, the catalyst delivers a current density of -0.9 A cm-2 with a Faradaic efficiency of nearly 79.6% for C2+ products, including 40% toward ethanol. This work highlights trace heteroatom-driven surface reconstruction as an effective strategy to engineer catalytic CO2 utilization.

ABSTRACT Precise control over reaction pathways and product selectivity is critical for advancing electrochemical CO 2 reduction reaction (CO 2 RR). Traditional strategies for promoting multicarbon production mainly rely on compositional tuning and architecture optimization. Here we report lattice chirality as a structural feature that biases reaction selectivity. As a proof of concept, chiral CuO nanoparticles were synthesized through thermal conversion of enantiopure Cu‐Cysteine precursors, producing lattice‐distorted nanoparticles while preserving the same crystal phase, morphology, and particle size as the achiral counterpart, which lacks lattice distortion. In CO 2 RR, the chiral‐derived nanostructures suppress the hydrogen evolution reaction and promote multicarbon formation, increasing the C 2+ /C 1 product ratio by up to 68.5% relative to the achiral counterpart. In situ spectroscopy combined with density‐functional theory calculations indicates that lattice chirality modulates the initial CO 2 activation and alters the population and evolution of surface intermediates (e.g., *CO and *OCCO species), favoring C−C coupling toward C 2+ products. Furthermore, lattice distortion increases the energetic cost of oxygen removal, contributing to slower reduction and altered structural evolution of the catalysts during operation compared with achiral counterparts. These results demonstrate that lattice chirality in CuO precatalysts biases reaction pathway selectivity in CO 2 RR, highlighting a potential parameter to modulate chemoselectivity in related multielectron catalytic reactions.

Recent advances in the acidic electroreduction of carbon dioxide (CO2) demonstrate the critical role of alkali metal cations (AM+) in driving CO2 activation and subsequent elementary steps. However, the effect of cation radius on CO2 reduction in acid remains inadequately understood. Herein, we investigate the size effect of AM+ (Cs+, K+, Na+, Li+) on CO2 reduction using a polycrystalline copper cathode in a flow cell in acid. In 1 M Cs+, the production of multi-carbon (C2+) products peaks with a Faradaic efficiency (FEC2+) of 63.2% at -500 mA cm-2. On the contrary, Li+ favors the production of methane with a FECH4 of 33.1% even at -70 mA cm-2. Kinetic analysis reveals the divergent roles of AM+ in regulating the CO2 activation step and the C-C coupling step, while in situ Raman spectroscopy demonstrates tunable surface coverage and configuration of *CO as well as the interface hydrophobicity in different AM+. By correlating electrochemical performance with spectroscopic findings, we elucidate how the cation size regulates the binding of key intermediates as well as the local water network, which in turn affect the activity of copper for CO2 reduction in acid.

Perfluorosulfonic acid ionomer, known as Nafion, has been frequently employed as a binder in electrode fabrication for electrocatalytic reduction of carbon dioxide, owing to its exceptional ionic conductivity and chemical robustness. However, the effect of Nafion on the catalytic interface hence the activity has been largely overlooked. Herein, we employ a Nafion-modified copper electrode for the electroreduction of carbon dioxide. The presence of Nafion with optimal amount surprisingly improves the selectivity of C-1 products, with a Faradaic efficiency of >80% at a current density of -50 mA cm(-2), comparing to a Faradaic efficiency of only 52% for C-1 products on a pristine copper. We reveal that the hydrophobic PTFE backbone in Nafion promotes the formation of HCOO-, while the -SO3H group is beneficial to the formation of CO. Employing in situ Raman spectroscopy, we reveal that Nafion alters the binding configuration of *CO intermediate and reduces *CO coverage on copper surface. Moreover, Nafion layer is found to reduce the availability of water molecules at the interface, impeding proton transfer and hindering C-C coupling process. Additionally, the tuning between C-1 molecules, i.e. the ratio between CO vs. HCOO-, is successfully achieved by adjusting the thickness of the copper catalyst and the maximum Faradaic efficiency of C-1 products reaches 85.5 %. This study underscores the unneglectable effect of Nafion on catalytic activity of copper electrode.

The electrocatalytic oxidation reaction of cyclohexanone (CHN) to adipic acid (COR), a crucial precursor for nylon-66, is impeded by weak substrate adsorption and sluggish Cu-H activation over a conventional Ni(OH)2 catalyst. Anion enhancement has been widely employed in such organic electrooxidations, yet the anion effect remains poorly understood. Here, we design NiSex as an anion-enhanced catalyst and uncover that in-situ generated SeO3 2- plays a triple role in COR, namely facilitating NiOOH formation, enhancing adsorption, and uniquely facilitating Cu-H activation. In-situ Raman and electrochemical analyses reveal the transformation of NiSex into a selenite-adsorbed NiOOH phase, which promotes the formation of active Ni3+ species. Decoupling mechanistic studies demonstrate that SeO32- not only strengthens CHN adsorption but also, uniquely among the anions tested, facilitates the ratedetermining Cu-H cleavage step and further COR process. Consequently, NiSex achieves a current density of 87 mA cm-2 at 1.54 V versus reversible hydrogen electrode, outperforming Ni(OH)2 by a factor of 3.6, as well as NiSx and NiPx, whose anion lacks this specific Cu-H activation enhancement. This work establishes a triple role of SeO32- and provides a decoupled framework for understanding anion effects for electrooxidation. (c) 2026 Published by Elsevier B.V. and Science Press on behalf of Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences.

A single noble metal atom combined with transition non-noble metals shows significant potential for improving atomic utilization of the former, thus reducing costs for practical water splitting application. Moreover, the rational design of catalysts with unique structure and proper compositions can increase the number of catalytic active sites, facilitate charges diffusion, and optimize adsorption energy of hydrogen ion to enhance hydrogen evolution reaction (HER). Herein, we synthesized a catalyst comprising single platinum atoms dispersed in nanoporous Ni metal (designated as sPtNi) supported by N-doped carbon, featuring an ultralow Pt loading of 0.5 wt%. Calculations using density functional theory indicate that the synergistic effects caused a low hydrogen adsorption free energy (-0.048 eV), hence promoting adsorbed hydrogen atom conversion and H2 desorption. Simultaneously, the incorporated Pt single atoms, possessing a downshifted d-band center in comparison to Ni metal, augment the electron transfer rate. Consequently, the sPtNi catalysts exhibited exceptional HER activity, exhibiting a low overpotential of 43 mV at 10 mA cm- 2 and a Tafel slope of 54.7 mV dec- 1. Moreover, the sPtNi catalyst exhibited high stability, with no dissolution observed in the solution even under-200 mA cm-2 for 100 h surpassing the most commercial Pt/C catalyst.

As key reaction intermediates involved in the electroreduction of carbon dioxide, *CO and *H (* represents active center) prove to be critical in regulating the selectivity toward different carbonaceous products. However, how the coverage of *H and *CO affects the selectivity of ethylene and ethanol remains unclear. In this work, we judiciously control the coverage of *CO or *H intermediates by introducing foreign metal into Cu nanoparticles, with the synthesis of four copper-based bimetallic catalysts, including CuAg, CuZn, CuCo, and CuPd. Four catalysts, together with Cu nanoparticles, are subjected to the electrochemical reduction of carbon dioxide in an H-cell. The CuZn catalyst is identified as the most effective catalyst for C & horbar;C coupling, exhibiting a Faradaic efficiency of 34.5% for C2+ products at -1.09 V versus RHE and a current density of -30.4 mA cm-2. In contrast, CuPd catalyst inclines to catalyze C & horbar;C coupling toward ethanol, with an FEethanol/FEethylene ratio reaching up to 1.15. The coverage of key intermediates is investigated through in situ Raman spectroscopy. The doping of Ag and Zn metals can enhance the adsorption of *CO on the catalyst, while the doping of Co and Pd metals can enhance the adsorption of *H on the catalyst. Hence, the increased *CO coverage on Ag- and Zn-doped CuNP promotes C2+ generation, and the increased *H coverage of Co- and Pd-doped CuNPs enhances the C2H5OH/C2H4 ratio.

Optimizing the electrocatalytic interface for the electroreduction of carbon dioxide (CO2) in acid through the usage of cations in the electrolyte has shown its effectiveness in enhancing CO2 conversion efficiency. However, such a positive impact in promoting CO2 activation is limited by the solubility of salt, hence alternative ways to optimize the interface shall be sought for. Here, the hydrophobicity of the catalytic interface is tuned through the judicious design of a sandwich-like structure by covering the catalytic copper layer with polytetrafluoroethylene (PTFE) particles. After optimizing the thickness of the PTFE layer on a commercial CuOX nanoparticle catalyst, an improved FE for multi-carbon products from 35.0% to 59.3% in 0.05 m H2SO4 electrolyte with the addition of 0.8 m K+ (pH = 1.6) is achieved. Moreover, in situ Raman spectroscopy proves that the hydrophobic layer facilitates the formation of *CO intermediates and promotes the transition of bridge-bonded *CO to atop-bonded *CO. The reduction of carbon monoxide (CO) is further performed at different partial pressures to reveal the critical role of *CO coverage for the formation of multi-carbon products. Collectively, it is proposed that the optimized hydrophobic modification of the catalyst effectively tunes the coverage of *CO intermediate as well as reduces the available water molecules at the interface, thereby promoting the formation of multi-carbon products and simultaneously suppressing hydrogen evolution reaction. The study illustrates a new venue toward improving the efficiency of CO2 conversion in acid.

In the electrochemical reduction of CO2, the employment of an acidic electrolyte with an alkali metal cation could reduce carbon loss. However, how the alkali metal cation activates CO2 and promotes the following proton-coupled electron transfer steps remains ambiguous. Here, from a rigorous analysis of CO2 reduction and CO reduction, we reveal that the kinetics of the CO2 electro-activation step and the following C-C coupling step both correlate positively with the concentration of K+, except that the promotion effect of K+ on the CO2-to-*CO step reaches a plateau when the concentration of K+ is >= 0.7 M under a high overpotential. The activity toward multicarbon products is determined by the dual cationic effect of K+ on the two steps, as evidenced in in situ Raman spectroscopy. The spectroscopic investigation shows that the adsorption of *CO shifts from atop configuration to bridge configuration as a net result of the dual cation effect, and the amount of adsorbed *OH increases with the rise of K+ concentration.

The chemical industry is electrifying toward a net-zero emission future. Unfortunately, the catalyst manufacturing process remains almost untouched in the transition to electrification due to challenges in size controllability and powder handling. Herein, we reported a slurry electrolysis strategy for scale-up production of Cu nanocatalysts at the productivity of 15 g per hour with a Cu loading of 2.5 wt % in laboratory flow electrolyzers, while maintaining excellent controllability of particle size down to single atoms by regulating the nucleation and particle growth process via pulsed electrochemistry. Our strategy can be further extended to the synthesis of Ag and CuAg catalysts for diverse electrochemical applications. Further techno-economic analysis shows an extremely low greenhouse gas emission and production cost (0.03 kgGHG and 16.4 USD per kg catalyst) compared to traditional approaches. This effectively addresses the productivity bottleneck in the electrosynthesis of nanocatalysts and paves the way for practical applications.

Understanding the determinants of local pH in acidic CO2 electroreduction (CO2R) is crucial for suppressing the competing hydrogen evolution reaction (HER). Here we reveal that although the interplay between the formation rate of current-induced OH- and the transport of H+ from the bulk electrolyte determines the local pH in acidic media, the construction of local alkalinity that mitigates HER from proton reduction is also closely linked to the presence of alkali cations owing to the conservation of local electroneutrality. Notably, we found the influence of cations on catalytic performance in acid (pH <= 1.2) strongly depends on the anion species by comparing the commonly used K2SO4 and KCl electrolytes in the acidic CO2R field. Under identical bulk pH adjusted with sulfuric acid, we found that the common-ion effect of the anion leads to a substantially larger amount of HSO4- when using K2SO4 electrolytes compared to the utilization of KCl electrolytes. The extra HSO4- in commonly used sulfate electrolytes not only offers an additional proton source for HER but also buffers the local pH during acidic CO2R. In situ Raman spectroscopy was employed to determine the trend of local pH variation, proving the role of the common-ion effect in the local pH.

Electrochemical reduction of carbon dioxide to value-added chemical feedstocks and fuels presents a promising strategy for carbon utilization and storage. Although advancements in enhancing the selectivity for C1 and C2 products have been witnessed, the research progress for efficient production of C3+ molecules remains slow. Moreover, the mechanism underlying carbon chain growth is still ambiguous. In this review, the recent developments in understanding how C-C coupling proceeds in the pathway toward C3+ molecules are mainly focused on. A few examples which reported the formation of C3-C6 molecules in electroreduction of carbon dioxide are first elaborated. Then, the production of 1-propanol, 2-propanol, 1-butanol, allyl alcohol, and propylene, with particular attention to the mechanism of carbon chain growth, is consecutively discussed. Moreover, alternatives for synthesizing valuable C3+ molecules from carbon dioxide, including tandem electrolyzer and electro-bio hybrid systems, are explored. The review is concluded with remarks on current challenges as well as perspectives on future research possibilities in electroreduction of carbon dioxide to C3+ chemicals and fuels.

The increasing level of atmospheric carbon dioxide (CO2) caused by intensified human activities has exacerbated the greenhouse effect, calling for the technology of CO2 fixation. Among the proposed technologies, electrocatalytic CO2 reduction in acidic electrolytes has garnered significant attention for its potential in sustainable carbon utilization and renewable energy storage. This review provides a summary of recent advancements in acidic CO2 reduction, with a focus on catalyst design strategies, the optimization of the local reaction environment, and the effect of cations. We first evaluated the performance and discussed the challenges for acidic CO2 reduction in H-type cells, flow cells, and membrane electrode assembly. Afterward, we highlight the innovative strategies for promoting CO2 reduction through optimizing the intrinsic activity and regulating the local environment of catalysts. The critical role of cations in enhancing CO2 reduction selectivity is also discussed. The review concludes with an outlook on future research directions, especially the need for the design of catalysts and systems that are stable, scalable, and highly efficient.

Electrosynthesis of carbon monoxide (CO) from carbon dioxide (CO2) and water driven by renewable electricity represents a sustainable route to carbon upgrading, but the lack of cost-effective catalysts hinders its scaling-up. Here, we judiciously designed a bimetallic Cu-In catalyst via in situ electroreduction of In-coated CuO nanowires. This facilely-prepared Cu-In catalyst delivers an excellent performance towards CO production in a flow cell, with a faradaic efficiency of CO of up to 91% at a geometric current density of -69 mA cm-2. Different from previous studies suggesting that In-modified Cu strengthens the adsorption of *COOH and/or weakens the binding of *H, we discovered that In acts as the active site. The modification of In by Cu weakens the adsorption of *CO. This facilitates a faster desorption of *CO, thus inhibiting the C-C coupling process. As a result, the formation of multi-carbon products is suppressed. This conclusion was drawn through a rigorous analysis of the electrochemical reduction of CO, the electrochemical adsorption of *CO and in situ Raman spectroscopy. Finally, we wired our CuIn-based electrolyzer to an efficient triple-junction solar cell for the demonstration of solar-driven CO2 conversion and achieved a solar-to-chemical energy conversion efficiency of greater than 10% for CO.

The electrochemical reduction of carbon dioxide (CO2) is potentially a sustainable approach to mitigating global CO2 emissions and simultaneously producing valuable feedstock. Though copper (Cu) is able to convert CO2 to various products, ranging from single-carbon molecules to even C3 product, the selectivity of polycrystalline Cu cathode is poor. Herein, we modify polycrystalline Cu through the interaction between Cu and the functional group by covering the surface with aniline. The interaction between aniline and Cu is intensively characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. Interestingly, the modified electrode shows an excellent activity toward the production of CO and HCOO-. Specifically, the aniline-modified electrode achieves a Faradaic efficiency of 68.1 ± 3.0% for the C1 product at a current density of -96 mA cm-2. Through a combined analysis of CO reduction, CO adsorption, and in situ Raman spectroscopy, we propose that the electronic interaction between aniline and Cu influences the adsorption strength of the CO intermediate, hence suppressing C-C coupling and promoting the formation of the C1 product. Our study provides new insight into developing modified Cu catalysts to promote the selectivity of Cu for CO2 electroreduction.

The conversion of carbon dioxide (CO 2 ) into value-added chemicals and renewable fuels is a promising approach to mitigate climate change and promote the development of sustainable energy systems. However, despite the broad range of products, including CO, formic acid and multi-carbon hydrocarbons, the large-scale implementation of CO 2 conversion technologies is still hindered by low catalytic efficiency and high energy consumption. This review introduces recent advances in catalytic materials design, emphasizing the structure–property relationships that govern the performance of highly efficient catalysts across various CO 2 conversion processes, including photocatalysis, electrocatalysis, CO 2 hydrogenation, photothermal conversion, non-thermal plasma techniques, and biological methodologies. By examining the synergies among catalyst architectures, key intermediates, catalytic mechanisms and reactor designs, this review explores the potential for tailored CO 2 conversion processes with optimized reaction pathways to achieve specific catalytic products, and also provides a roadmap for the development of efficient, scalable CO 2 conversion technologies to facilitate the transition to a circular carbon economy.

The development of highly active and SO2-resistant catalysts is a major hurdle in the catalytic oxidation of NO to NO2. Herein, we fabricate a core-shell Mn2O3 @CeO2 catalyst using a two-step method for NO oxidation. Benefiting from the generation of abundant Mn4+-Ov- Ce3+ interfacial sites and plentiful oxygen vacancies, the resulting Mn2O3 @CeO2 exhibits a superior low-temperature NO-to-NO2 capacity (T50 at 183 degrees C and T86 at 275 degrees C), obtaining a remarkable temperature reduction compared to commercial Pt/gamma-Al2O3 catalyst (T50 at 262 degrees C). Meanwhile, In-situ Raman and In-situ Drifts reveal that Mn4+-Ov- Ce3+ interfacial site is the main adsorption site for the formation of N-containing intermediates, which plays a decisive role in the NO oxidation reaction. More encouragingly, SO2 shows a much higher affinity for CeO2 sheath (ECeO2,SO2= -3.48 eV) than Mn2O3 core (EMn2O3,SO2= -0.87 eV), thus avoiding its toxic effects on the interior active sites and endowing Mn2O3 @CeO2 a superior SO2-resistance.

The design of efficient and active electrocatalysts for the oxygen evolution reaction (OER) is crucial for hydrogen generation from water electrolysis. Here, crystalline iron-doped nickel sulfide core-amorphous iron-doped nickel phosphate shell heterostructured nanosheets grown on nickel foam (Ni0.9Fe0.1S@NiFe(PO4)x/NF) are prepared by a solvothermal reaction of nickel iron layered double hydroxides on NF (NiFe-LDH/NF) with P2S5. The heterogeneous interface induces the electronic interaction between the Ni0.9Fe0.1S and NiFe(PO4)x phases, which is beneficial for the OER. The electrode exhibits excellent OER performance, requiring only 208 mV and 246 mV at current densities of 10 mA cm-2 and 100 mA cm-2, respectively, and a low Tafel slope of 38.75 mV dec-1 in 1 M KOH. The OER mechanistic pathways of both Ni0.9Fe0.1S@NiFe(PO4)x/NF and NiFe-LDH/NF involve decoupled electron and proton transfer processes. The increase in the acidity of Ni sites leads to the enhanced participation of LOM for Ni0.9Fe0.1S@NiFe(PO4)x/NF. Additionally, the electrode also shows long-term durability (150 h), with the conversion of surface metal sulfides and phosphates to hydroxides and (oxy)hydroxides.

The cover image is based on the Review Updates on Hydrogen Value Chain: A Strategic Roadmap by Julio Garcia-Navarro et al., https://doi.org/10.1002/gch2.202300073 Image Credit: Júlio Arvellos