Renewable energy-driven electrochemical CO2 reduction has emerged as a promising technology for a sustainable future. However, achieving efficient production of storable liquid fuels at ampere-level current densities remains a significant hurdle in the large-scale implementation of CO2 electroreduction. Here we report a novel catalytic electrode comprising chlorine-doped SnO2 nanoflowers arrayed on the exterior of three-dimensional nickel hollow fibers. This electrode demonstrates exceptional electrocatalytic performance for converting CO2 to formate, achieving a remarkable formate selectivity of 99 % and a CO2 single-pass conversion rate of 93 % at 2 A cm(-2). Furthermore, it exhibits excellent stability, maintaining a formate selectivity of above 94 % for 520 h at a current density of 3 A cm(-2). Experimental results combined with theoretical calculations confirm that the enhanced mass transfer facilitated by the hollow fiber penetration effect, coupled with the well-retained Sn4+ species and Sn-Cl bonds, synergistically elevates the activity of CO2 conversion. The incorporation of chlorine into SnO2 enhances electron transport and CO2 adsorption, substantially lowering the reaction energy barrier for the crucial intermediate *OCHO formation, and boosting the formate production.

Synthesis of valuable chemicals from CO2 electroreduction in acidic media is highly desirable to overcome carbonation. However, suppressing the hydrogen evolution reaction in such proton-rich environments remains a considerable challenge. The current study demonstrates the use of a hollow fiber silver penetration electrode with hierarchical micro/nanostructures to enable CO2 reduction to CO in strong acids via balanced coordination of CO2 and K+/H+ supplies. Correspondingly, a CO faradaic efficiency of 95% is achieved at a partial current density as high as 4.3 A/cm2 in a pH = 1 solution of H2SO4 and KCl, sustaining 200 h of continuous electrolysis at a current density of 2 A/cm2 with over 85% single-pass conversion of CO2. The experimental results and density functional theory calculations suggest that the controllable CO2 feeding induced by the hollow fiber penetration configuration primarily coordinate the CO2/H+ balance on Ag active sites in strong acids, favoring CO2 activation and key intermediate *COOH formation, resulting in enhanced CO formation.

CO2 electroreduction to valuable chemicals using renewable energy is a prospective strategy for realizing carbon neutrality, however, exclusive production of formate under high industry current densities (> 200 mA cm(-2)) remains challenging. Herein, we presented a lattice-dislocated hollow-fiber Bi via in situ reconstruction to make a breakthrough for such issue. A nearly perfect formate Faradaic efficiency of > 99.5 % was realized with a current density of 1 A cm(-2), completely suppressing CO and hydrogen generation. Finite element simulations showed high-concentration CO2 feeding was realized even though at ampere-level current density. And density functional theory calculations revealed that the abundant dislocated lattice acting as the active sites boosted the production of OCHO* . Thus, the synergistic combination of penetration and strain effects induced by the latticedislocated Bi hollow penetration electrode is responsible for such remarkable activities. This work represents a large step toward the application of direct conversion of CO2.

The synthesis of multicarbon (C 2+ ) products remains a substantial challenge in sustainable CO 2 electroreduction owing to the need for sufficient current density and faradaic efficiency alongside carbon efficiency. Herein, we demonstrate ampere-level high-efficiency CO 2 electroreduction to C 2+ products in both neutral and strongly acidic (pH=1) electrolytes using a hierarchical Cu hollow-fiber penetration electrode (HPE). High concentration of K + could concurrently suppress hydrogen evolution reaction and facilitate C−C coupling, thereby promoting C 2+ production in strong acid. By optimizing the K + and H + concentration and CO 2 flow rate, a faradaic efficiency of 84.5 % and a partial current density as high as 3.1 A cm −2 for C 2+ products, alongside a single-pass carbon efficiency of 81.5 % and stable electrolysis for 240 h were demonstrated in a strong acidic solution of H 2 SO 4 and KCl (pH=1). Experimental measurements and density functional theory simulations suggested that tensile-strained Cu HPE enhances the asymmetric C−C coupling to steer the selectivity and activity of C 2+ products.

The electrochemical propylene epoxidation reaction (PER) provides a promising route for ecofriendly propylene oxide (PO) production, instantly generating active halogen/oxygen species to alleviate chloride contamination inherent in traditional PER. However, the complex processes and unsatisfactory PO yield for current electrochemical PER falls short of meeting industrial application requirements. Herein, a spatial-coupling strategy over RuO 2 /Ti hollow-fiber penetration electrode (HPE) is adopted to facilitate efficient PO production, significantly improving PER performance to ampere level (achieving over 80 % PO faradaic efficiency and a maximum PO current density of 859 mA cm −2 ). The synergetic combination of the penetration effect of HPE and the spatial-coupled reaction sequence, enables the realization of ampere-level PO production with high specificity, exhibiting significant potentials for economically viable PER applications.

Artificial photosynthesis, which utilizes sunlight to produce value-added chemicals and fuels from CO2, is a promising strategy to storage fluctuating solar energy and to realize zero carbon cycle simultaneously. While selective C2+ production via CO2 photoelectrocatalytic conversion remains a challenge due to the sluggish C -C coupling kinetics over current artificial photosynthesis catalysts. Herein, we present a carbon @ silicon carbide (C@SiC) catalyst for ambient CO2 photoelectric reduction under simulated solar irradiation, giving a CO2 conversion rate of 487 mu mol center dot gcat - 1 center dot h- 1 with an ethanol selectivity of 87.8%. The optimal sp2/sp3 carbon ratio of carbon layer not only facilitates the photo -generated electrons transfer from SiC to carbon layer, but also favors the C -C coupling kinetics of key intermediates for efficient CO2 to ethanol conversion.

Electroreduction of CO2 to chemical fuels is desirable for the economically viable use of CO2 and consumption of renewable electricity. Efficient production of C2+ on Cu-based catalysts remains a challenge. Herein, a copper hollow fiber penetration electrode with a striking C-C coupling capability by virtue of modulating the electronic states through halide ion coordinated adsorption. An efficient C2+ production with a FE of 68.8 % at 2.1 A cm-2 in 3.0 M KI and remained stable during 120-h electrolysis at 2.0 A cm-2, outperforming reported catalytic performance, which is the result of combined effect of penetration effect and halide ion coordinated adsorption, which promotes the transfer of electrons to CO2, reduces the C-C coupling energy and suppresses proton adsorption, thereby reducing hydrogen evolution.

Sufficient CO 2 feeding induced by the hollow-fiber penetration configuration greatly improved CO 2 coverage on Cu active sites in strong acids, favoring CO 2 activation, *CHO and *CO formation, and their couplings to C 2+ products.

The titanium-based metal-organic framework MIL-125(Ti) has been widely investigated in photocatalytic carbon dioxide reduction and water splitting, but rarely studied in photocatalytic methane conversion by employing only water as an oxidant under mild conditions. Simultaneously controlling products with high yield and selectivity is highly challenging in methane conversion. Herein, we develop a series of functionalized titanium metal-organic frameworks via a facile organic ligand exchange process. The abundant Ti3+ active sites induced by oxygen vacancies and functionalized ligands synergistically facilitate the adsorption and activation of methane molecules. The carbon monoxide yield over NH2-MIL-125(Ti) increased to 198.6 mu mol center dot g(cat)(-1)center dot h(-1) with a high selectivity of 87.1 % under simulated solar illumination. Combined with in-situ characterizations and density functional theoretical calculations, the results confirmed that Ti3+ active sites induced by oxygen vacancies and amino functional groups synergistically enhanced the photocatalytic conversion of methane and elucidate CH4-to-CO conversion mechanism. This study does not only provide insights into the rational design of metal-organic frameworks with copious oxygen vacancies and functional groups, but also provides some significant cognition for photocatalytic methane conversion.

Electroreduction of CO2 to CO is a promising route for greenhouse gas resource utilization, but it still suffers from impractical current density and poor durability. Here, a nanosheet shell (NS) vertically standing on the Ag hollow fiber (NS@Ag HF) surface formed by electrochemical surface reconstruction is reported. As-prepared NS@Ag HF as a gas penetration electrode exhibited a high CO faradaic efficiency of 97% at an ultra-high current density of 2.0 A cm(-2) with a sustained performance for continuous >200 h operation. The experimental and theoretical studies reveal that promoted surface electronic structures of NS@Ag HF by the nanosheets not only suppress the competitive hydrogen evolution reaction but also facilitate the CO2 reduction kinetics. This work provides a feasible strategy for fabricating robust catalysts for highly efficient and stable CO2 reduction.

Substituting sluggish oxygen evolution reaction (OER) with glycerol electrooxidation reaction (GER) to formate is a promising strategy for addressing glycerol overproduction and hydrogen production efficiency concurrently. However, the poor formate selectivity and the use of noble-metal catalysts hamper electrolysis applications of glycerol. Herein, we present a commercial nickel foam-supported nickel cobaltite (NiCo2O4/NF) synthesized via a facile hydrothermal/annealing combined process. The as-synthesized earth-abundant metal oxide composite enables anodic GER to formate, achieving not only as low as potential of 1.23 V (vs. reversible hydrogen electrode, RHE) to deliver 10 mA cm � 2, but also a large catalytic current density of 152 mA cm-2 with an exceeding formate faradic efficiency (FE) of 97 % at 1.6 V (vs. RHE). Synergy effect induced by intermetallic interactions of hierarchical NiCo2O4 nanostructures rooted in Ni foam substrate facilitates anodic oxidation of glycerol and assists cathodic hydrogen production simultaneously. In particular, a two-electrode electrolyser NiCo2O4/NF || Ni foam requires a cell voltage of as low as 1.35 V to achieve 10 mA cm � 2, which is 320 mV lower than that of the conventional overall water splitting systems.

Efficient C2+ production from CO2 electrocatalytic reduction exhibits significant promise but suffers from low selectivity and undesired side reactions. Stepwise electroreductions of CO2 to CO and then to C2+ products can benefit from the perfect cooperation of the first high CO production efficiency and the subsequent favorable C-C coupling kinetics of CO. Herein, by virtue of serial Ag and Cu hollow-fiber penetration electrodes, a highefficiency CO2 electroreduction to C2+ products is achieved with a partial current density of 1.8 A cm-2 and a faradaic efficiency of 90.5 %. Experimental results and density functional theory calculations demonstrate that the synergetic combination of unique penetration effect induced by hierarchical micro/nanostructured hollow fiber configurations and regulated electronic structures by chloride ion adsorption, is responsible for the superior activity. This work provides a facile tactic and encouraging headway to design applicable efficient CO2 electrocatalytic reduction systems towards high-value C2+ chemicals.

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

Partial positive valence Cu (Cu delta+) sites on Cu-based electrocatalysts are important for C-C coupling to form C2+ products; however, maintaining the stability of Cu delta+ remains a challenge. Herein, an ultrastable Cu delta+ (0 < delta < 1) site over the copper penetration electrode was constructed using boron to tailor the *CO adsorption strength and configuration for facilitating C-C coupling, which achieves a C2+ Faradaic efficiency (FE) of 78.9% at -0.91 V (vs reversible hydrogen electrode), of which the ethanol FE reaches 52.4% with an ultrahigh partial current density of 1.25 A cm(-2), far outperforming state-of-the-art electrocatalysts, corresponding to the ethanol cathodic energy efficiency (CEE) of 27.7%. Spectroscopy and computation results show that introducing boron to optimize the coordination numbers and oxidation states of surface Cu atoms enables enrichment of locally asymmetric *COatop and *CHO intermediates to trigger asymmetric C-C coupling to form ethanol.

Carbon dioxide electroreduction driven by renewable electricity into high‐value chemicals enables energy storage while contributing to climate change mitigation. Herein, a CuPd bimetallic catalyst is developed by electrodeposition for efficient CO2 electroreduction, achieving a C2+ Faradaic efficiency as high as 75.6% with a current density of −200 mA cm−2 at −1.15 V versus reversible hydrogen electrode. Upon incorporation of Pd, the average d‐band center of the CuPd bimetallic catalyst downward shifts relative to the Fermi level, making the adsorbed CO intermediates active for further C–C coupling. Theoretical calculations confirm that CO generated on the Pd domain can spill over to the CuPd interface for C–C coupling with a lower energy barrier, further promoting the formation of C2+ compounds. This study provides insights into the rational design of Cu‐based bimetallic catalysts for highly efficient CO2 electroreduction to multicarbon products.

As one of the most important derivatives of propylene, the production of propylene oxide (PO) is severely restricted. The traditional chlorohydrin process is being eliminated due to environmental concerns, while processes such as Halcon and hydrogen peroxide epoxidation are limited by cost and efficiency, making it difficult to meet market demand. Therefore, achieving PO production through clean and efficient technologies has received extensive attention, and halogen-mediated electrochemical epoxidation of alkene is considered to be a desirable technology for the production of alkylene oxide. In this work, we used electrochemical methods to synthesize PO in halogen-mediated systems based on a RuO2-loaded Ti (RuO2/Ti) anode and screened out two potential mediated systems of chlorine (Cl) and bromine (Br) for the electrosynthesis of PO. At a current density of 100 mA·cm-2, both Cl- and Br-mediated systems delivered PO Faradaic efficiencies of more than 80%. In particular, the Br-mediated system obtained PO Faradaic efficiencies of more than 90% at lower potentials (≤1.5 V vs RHE) with better electrode structure durability. Furthermore, detailed product distribution investigations and DFT calculations suggested hypohalous acid molecules as key reaction intermediates in both Cl- and Br-mediated systems. This work presents a green and efficient PO production route with halogen-mediated electrochemical epoxidation of propylene driven by renewable electricity, exhibiting promising potential to replace the traditional chlorohydrin process.

A hierarchical micro/nanostructured Cu(100)-rich copper hollow fiber as a gas penetration electrode (GPE) efficiently reduces CO2to C2+products.

Efficient conversion of CO2 to commodity chemicals by sustainable way is of great significance for achieving carbon neutrality. Although considerable progress has been made in CO2 utilization, highly efficient CO2 conversion with high space velocity under mild conditions remains a challenge. Here, we report a hierarchical micro/nanostructured silver hollow fiber electrode that reduces CO2 to CO with a faradaic efficiency of 93% and a current density of 1.26 A · cm-2 at a potential of -0.83 V vs. RHE. Exceeding 50% conversions of as high as 31,000 mL · gcat-1 · h-1 CO2 are achieved at ambient temperature and pressure. Electrochemical results and time-resolved operando Raman spectra demonstrate that enhanced three-phase interface reactions and oriented mass transfers synergistically boost CO production.

Electrochemical conversion of CO 2 into valuable feedstocks is a promising strategy for carbon neutrality. However, it remains a challenge to possess a large current density, a high faradaic efficiency and excellent stability for practical applications of CO 2 utilization. Herein, we report a facile tactic that enables exceedingly efficient CO 2 electroreduction to CO by virtue of low-coordination chloride ion (Cl − ) adsorption on a silver hollow fiber (Ag HF) electrode. A CO faradaic efficiency of 92.3 % at a current density of one ampere per square centimeter (1 A cm −2 ) in 3.0 M KCl with a sustained performance observed during a 150-hour test was achieved, which is better than state-of-the-art electrocatalysts. The electrochemical results and density functional theory (DFT) calculations suggested a low-coordination Cl − adsorption on surface of Ag HF, which not only suppressed the competitive hydrogen evolution reaction (HER), but also facilitated the CO 2 reduction kinetics.

Abstract: The valence states of copper always play an important role for the most studied copper-based catalysts in CO2 electroreduction (CO2ERR). In this work, distinct Cu, Cu2O, and CuO nanoparticles with similar particle size on active carbon are synthesized via carbonthermal reduction. Although all CuOx nanoparticles are reduced to metallic Cu during CO2ERR, their different initial valence states result in particle-size variations and different CO2ERR performances. Cu nanoparticles in Cu/C evolve into smaller particles, while those derived from Cu2O/C and CuO/C agglomerate into larger ones. The optimal CO production potential of CO drops with decreasing particle size and is as low as -0.7 V (vs. the eversible hydrogen electrode) on Cu/C. Furthermore, Cu nanoparticles in Cu/C expose much more active sites with higher electrochemical active area and stronger CO adsorption, which further promote C-C coupling to produce C2+ products while inhibiting competitive hydrogen evolution.