Anodic Current Research Articles

Unique Oxygen-Bridged Nickel Atomic Pairs Efficiently Boost Electrochemical Reduction of Carbon Dioxide.

Benefiting from the synergism between adjacent bimetallic atoms, in comparison with single atom catalysts, the dual atom catalysts have displayed great potential in electrocatalytic CO2 reduction reaction (CO2RR). However, the further modulation of the electronic structure of dual atom sites to enhance CO2RR performance still remains a challenge. Herein, an atomically dispersed oxygen-bridged Ni2N6O/NC catalyst with unique Ni-O-Ni sites is successfully synthesized through the microwave pyrolysis of the supported mixture containing the dinuclear nickel phthalocyanine and glucose on N-doped carbon nanosheets. Experiments and density functional theory calculation reveal that the Ni-O-Ni sites can adsorb H+ from the KHCO3 electrolyte to in situ-form the unique Ni-OH-Ni sites without Ni─Ni bonding interaction, which effectively lowers the energy barrier towards the formation of *COOH from CO2. As a result, the Ni2N6OH/NC catalyst exhibits a 99.4% of CO Faradaic efficiency with a 32.4 mA·cm-2 of CO partial current density at -0.7V versus RHE in H-cell, much superior to the Ni2N6/NC with a Ni-Ni bonding interaction prepared by a similar procedure to that for Ni2N6O/NC but replacing microwave pyrolysis by a traditional heating process.

Impact of Side Chains in 1-n-Alkylimidazolium Ionomers on Cu-Catalyzed Electrochemical CO2 Reduction.

This 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 chemicalsynthesis.

Integrated “Two‐in‐One” Strategy for High‐Rate Electrocatalytic CO2 Reduction to Formate

AbstractThe electrochemical CO2 reduction reaction (ECR) is a promising pathway to producing valuable chemicals and fuels. Despite extensive studies reported, improving CO2 adsorption for local CO2 enrichment or water dissociation to generate sufficient H* is still not enough to achieve industrial‐relevant current densities. Herein, we report a “two‐in‐one” catalyst, defective Bi nanosheets modified by CrOx (Bi−CrOx), to simultaneously promote CO2 adsorption and water dissociation, thereby enhancing the activity and selectivity of ECR to formate. The Bi−CrOx exhibits an excellent Faradaic efficiency (≈100 %) in a wide potential range from −0.4 to −0.9 V. In addition, it achieves a remarkable formate partial current density of 687 mA cm−2 at a moderate potential of −0.9 V without iR compensation, the highest value at −0.9 V reported so far. Control experiments and theoretical simulations revealed that the defective Bi facilitates CO2 adsorption/activation while the CrOx accounts for enhancing the protonation process via accelerating H2O dissociation. This work presents a pathway to boosting formate production through tuning CO2 and H2O species at the same time.

Constructing Ag/Cu2O interface for efficient neutral CO2 electroreduction to C2H4.

Neutral CO2 electroreduction to multi-carbons (C2+) offers a promising pathway to reduce the CO2 and energy losses originating from the carbonate formation. However, the sluggish kinetics of C-C coupling brings a significant challenge of achieving high selectivity of a single product (such as ethylene), especially at industrial-relevant current densities (> 300 mA cm-2). Here, we reported an optimized Ag-Cu2O interfacial catalyst that exhibited C2+ Faradaic efficiency (FE) of 73.6% at 650 mA cm-2 in a flow cell. Remarkably, it obtained FEC2H4 of 66.0% with a partial current density of 429.1 mA cm-2, making it stand out among the reported Cu-based electrocatalysts. In situ Raman spectra uncovered that the Ag/Cu2O interfaces enabled a high coverage of *CO around the partially reduced Cu+/Cu0 active sites. Furthermore, theoretical calculations demonstrated the enhanced CO formation and C-C coupling at the Ag/Cu2O interface. This work reported an unprecedented neutral CO2 electroreduction to C2H4 performance and provided an in-depth comprehension of the role of the bimetallic interface.

Constructing Ag/Cu2O interface for efficient neutral CO2 electroreduction to C2H4

Neutral CO2 electroreduction to multi‐carbons (C2+) offers a promising pathway to reduce the CO2 and energy losses originating from the carbonate formation. However, the sluggish kinetics of C–C coupling brings a significant challenge of achieving high selectivity of a single product (such as ethylene), especially at industrial‐relevant current densities (> 300 mA cm−2). Here, we reported an optimized Ag‐Cu2O interfacial catalyst that exhibited C2+ Faradaic efficiency (FE) of 73.6% at 650 mA cm−2 in a flow cell. Remarkably, it obtained FEC2H4 of 66.0% with a partial current density of 429.1 mA cm−2, making it stand out among the reported Cu‐based electrocatalysts. In situ Raman spectra uncovered that the Ag/Cu2O interfaces enabled a high coverage of *CO around the partially reduced Cu+/Cu0 active sites. Furthermore, theoretical calculations demonstrated the enhanced CO formation and C–C coupling at the Ag/Cu2O interface. This work reported an unprecedented neutral CO2 electroreduction to C2H4 performance and provided an in‐depth comprehension of the role of the bimetallic interface.

Enhanced Local CO Coverage on Cu Quantum Dots for Boosting Electrocatalytic CO2 Reduction to Ethylene

AbstractEthylene (C2H4) electrosynthesis from the electrocatalytic CO2 reduction process holds enormous potential applications in industrial production. However, the sluggish kinetics of C─C coupling often result in low yield and poor selectivity for C2H4 production. Herein, the performance of Cu catalysts of varying sizes is investigated, prepared via a cryo‐mediated liquid phase exfoliation technique, for the electrochemical CO2 reduction to C2H4. The activity and selectivity of C2H4 gradually increase as the size of the Cu catalysts decreases from tens of nanometers to a few nanometers. Impressively, the 5 nm Cu quantum dots (Cu‐5) achieve a maximum C2H4 Faradaic efficiency (FE) of 81.5% and a half‐cell cathodic energy efficiency (CEE) of 42.2% with a large partial current density of 1.1 A cm−2 at −0.93 V versus the reversible hydrogen electrode. Structural characterization and in situ spectroscopic analysis reveal that the Cu‐5 quantum dots, dominated by the (100) facet, provide an abundance of active sites that enhance CO2 adsorption and activation, promoting the formation of *CO intermediates. The accumulation of *CO intermediates on the Cu active sites facilitates the CO‐CHO coupling reaction, thus enhancing the C2H4 production rate.

Unravelling the Effect of Crystal Facet of Derived-Copper Catalysts on the Electroreduction of Carbon Dioxide under Unified Mass Transport Condition.

Altering the physical structure and chemical property of copper, i.e., particle size, surface morphology, composition or crystal facet, has been demonstrated to be effective in steering the selectivity of products in electrochemical reduction of carbon dioxide. However, these modifications generally result in the change of active surface area, leading to differences in the geometric current density and local pH, which are also demonstrated to be the key factors for observed selectivity change. In this work, we deconvolute the effect of mass transport and local pH from the effect of crystal facet by investigating five copper-based catalysts with identical roughness factors for electrochemical reduction of carbon dioxide in an H-cell. Interestingly, CuO-derived catalyst stands out as the best catalyst for C-C coupling. At -1.07 V vs. RHE, the faradaic efficiency of C2+ product reaches 44.3%, with a partial current density of -10.8 mA cm-2. Electrochemical adsorption of *OH reveals that the C2+ product selectivity of derived-copper catalysts correlates positively with the ratio of Cu(100)/Cu(110) of five catalysts. Additionally, in situ Raman spectroscopy reveals that the percentage of low-frequency band linear CO (LFB-CO), which is attributed to the adsorbed *CO on Cu(100) facet, increases with the C-C coupling efficiency.

Unravelling the Effect of Crystal Facet of Derived‐Copper Catalysts on the Electroreduction of Carbon Dioxide under Unified Mass Transport Condition

Altering the physical structure and chemical property of copper, i.e., particle size, surface morphology, composition or crystal facet, has been demonstrated to be effective in steering the selectivity of products in electrochemical reduction of carbon dioxide. However, these modifications generally result in the change of active surface area, leading to differences in the geometric current density and local pH, which are also demonstrated to be the key factors for observed selectivity change. In this work, we deconvolute the effect of mass transport and local pH from the effect of crystal facet by investigating five copper‐based catalysts with identical roughness factors for electrochemical reduction of carbon dioxide in an H‐cell. Interestingly, CuO‐derived catalyst stands out as the best catalyst for C‐C coupling. At ‐1.07 V vs. RHE, the faradaic efficiency of C2+ product reaches 44.3%, with a partial current density of ‐10.8 mA cm‐2. Electrochemical adsorption of *OH reveals that the C2+ product selectivity of derived‐copper catalysts correlates positively with the ratio of Cu(100)/Cu(110) of five catalysts. Additionally, in situ Raman spectroscopy reveals that the percentage of low‐frequency band linear CO (LFB‐CO), which is attributed to the adsorbed *CO on Cu(100) facet, increases with the C‐C coupling efficiency.

Oriented Synthesis of Glycine from CO2, N2, and H2O via a Cascade Process

AbstractAir contains carbon, hydrogen, oxygen, and nitrogen elements that are essential for the constitution of amino acids. Converting the air into amino acids, powered with renewable electricity, provides a green and sustainable alternative to petrochemical‐based methods that produce waste and pollution. Here, taking glycine as an example, we demonstrated the complete production chain for electrorefining amino acids directly from CO2, N2, and H2O. Such a prospective Scheme was composed of three modules, linked by a spontaneous C−N bond formation process. The high‐purity bridging intermediates, separated from the stepwise synthesis, boosted both the carbon selectivity from CO2 to glycine of 91.7 % and nitrogen selectivity from N2 to glycine of 98.7 %. Under the optimum condition, we obtained glycine with a partial current density of 160.8 mA cm−2. The high‐purity solid glycine product was acquired with a separation efficiency of 98.4 %. This work unveils a green and sustainable method for the abiotic creation of amino acids from the air components.

Structural Features of Porous Silicon Formed on Heavily Doped Plates of Single-Crystal Silicon with Electron Conductivity

Using scanning electron microscopy, the structures of the surface and internal regions of porous silicon obtained by anodizing heavily doped plates of single-crystal silicon with electron conductivity in a hydrofluoric acid solution at different current densities were studied. It is found that the porous silicon surface has dark gray and light gray pores, which differ in size and surface distribution density. Dark gray pores possess larger sizes, and their density is about 5–10 times less than that of light gray pores. Based on the cross-section imagery, it is shown that light gray pores correspond to underdeveloped channels of small depth, while dark gray pores are the entrance points of deep bottle-shaped channels passing from the surface into the depth of the silicon wafer. The equivalent diameters of light gray pores on the surface of porous silicon are 12–15 nm and are practically independent of the anodic current density. At the same time, the equivalent diameters of dark gray pores and average distances between their centers increase linearly from 15 to 35 nm on the surface and from 35 to 120 nm in the volume of porous silicon when the current density is increased from 30 to 90 mA/cm2. The average thickness of silicon skeleton elements is about 3 nm on the surface and increases to 5–6 nm in the volume. By setting the density of the anode current, it is possible to obtain layers of porous silicon with different structural parameters. The obtained research results have practical significance for the formation of composite materials based on porous silicon, which can be used as a porous matrix for the deposition of metals and semiconductors.

Selective CO2 Reduction Electrocatalysis Using AgCu Nanoalloys Prepared by a "Host-Guest" Method.

Multimetallic nanoalloy catalysts have attracted considerable interest for enhancing the efficiency and selectivity of many electrochemically driven chemical processes. However, the preparation of homogeneous bimetallic alloy nanoparticles remains a challenge. Here, we present a room-temperature and scalable, host-guest approach for synthesis of dilute Cu in Ag alloy nanoparticles. In this approach, an ionic silver bromide precursor harboring exogenous Cu cations is reduced to yield ∼20 nm diameter AgCu alloy nanoparticles wherein the % Cu loading can be tuned precisely. AgCu nanoparticles with a 5% nominal loading of Cu exhibit peak activity (-0.23 mA/cm2 normalized partial current density) and selectivity (83.2% faradaic efficiency) for CO product formation from electrocatalytic reduction of CO2 at mild overpotentials. These AgCu nanoalloys exhibit a higher mass activity compared to Ag- and Cu-containing nanomaterials used for similar electrocatalytic transformations. Our host-guest synthesis platform holds promise for production of other nanoalloys with relevance in electrocatalysis and optics.

Tailoring Interlayer Microenvironment of 2D Layered Double Hydroxides for CO2 Reduction with Enhanced C2+ Production.

Both the physicochemical properties of catalytic material and the structure of loaded catalyst layer (CL) on gas diffusion electrode (GDE) are of crucial importance in determining the conversion efficiency and product selectivity of carbon dioxide reduction reaction (CO2RR). However, the highly reducing reaction condition of CO2RR will lead to the uncontrollable structural and compositional changes of catalysts, making it difficult to tailor surface properties and microstructure of the real active species for favored products. Herein, the interlayer microenvironment of copper-based layered double hydroxides (LDHs) is rationally tuned by a facile ink solvent engineering, which affects both the surface characters and microstructure of CL on GDE, leading to distinct catalytic activity and product selectivity. According to series of in situ and ex situ techniques, the appropriate surface wettability and thickness of porous CL are found to play critical roles in controlling the local CO2 concentration and water dissociation steps that are key for hydrogenation during CO2RR, leading to a high Faradaic efficiency of 75.3% for C2+ products and a partial current density of 275mAcm-2 at -0.8V versus RHE. This work provides insights into rational design of efficient electrocatalysts toward CO2RR for multi-carbon generation.

In Situ Transformation of Hybrid Bismuth Halide into Rhombohedral Bismuth for Electrochemical CO2 Reduction to Formate

AbstractBi‐based electrocatalysts have attracted high attention due to their high selectivity for formate, low cost, and high biocompatibility. Surface modification with halides can adjust the surface charge distribution of metal catalysts, thereby regulating the binding force of the intermediate. Organic‐inorganic hybrid bismuth halides provide an alternative, especially low dimensional structures. Herein, zero‐dimensional hybrid bismuth halides containing Bi4I16 units (denoted as Bi4I16) was recommended as pre‐catalyst due to the Bi ⋅ ⋅ ⋅ Bi spacing in Bi4I16 is 4.760 Å, nearly equaling to the Bi ⋅ ⋅ ⋅ Bi spacing in rhombohedral Bi (4.750 Å). The equal spacing may be more beneficial for the electricity‐driven in situ conversion and rearrangement of Bi atoms in the catalytic process. As a contrast, zero‐dimensional bismuth halide containing Bi2I9 units (denoted as Bi2I9) with shorter Bi ⋅ ⋅ ⋅ Bi spacing (4.2415 Å) was prepared. The working electrode prepared by Bi4I16 ink was measured for CO2RR, and the partial formate current density can reach 8.2 mA cm−2 at −1.1 V vs RHE. The Bi4I16 catalyst delivers a maximum Faradaic Efficiency (FE, ~80 %) for formate at −0.86 V vs RHE and maintain a FE higher than 78.5 % after 16 h.

Dynamic response characteristics of proton exchange membrane fuel cell during transient loading: An experiment study

The dynamic performance of Proton Exchange Membrane Fuel Cell (PEMFC) is crucial for safe and efficient operation and remains a major barrier to commercialization. In this paper the dynamic response characteristics of PEMFC under serpentine flow field (SFF) and parallel flow field (PFF) are discussed. The effects of current loading, operating pressures, anode and cathode stoichiometric ratios, as well as operating temperatures on the dynamic response characteristics of PEMFC are systematically studied through experimental methods. Furthermore, the principle and mitigation strategies for voltage undershoot are investigated. It shows that lower current density, higher back pressure and higher temperature are benefit to alleviate voltage undershoot. Compared with the SFF, the Second-stage time delay of PFF is shortened by 9.2 s, the VU is decreased by 17.27 mV, and the energy loss is reduced by 0.71%. Moreover, Pearson correlation coefficient is proposed to evaluate the correlation between index and PEMFC performance.

Establishing Non-stoichiometric Ti4O7 Assisted Asymmetrical C-C Coupling for Highly Energy-Efficient Electroreduction of Carbon Monoxide.

Exploring an appropriate support material for Cu-based electrocatalyst is conducive for stably producing multi-carbon chemicals from electroreduction of carbon monoxide. However, the insufficient metal-support adaptability and low conductivity of the support would hinder the C-C coupling capacity and energy efficiency. Herein, non-stoichiometric Ti4O7 was incorporated into Cu electrocatalysts (Cu-Ti4O7), and served as a highly conductive and stable support for highly energy-efficient electrochemical conversion of CO. The abundant oxygen vacancies originated from ordered lattice defects in Ti4O7 facilitate the water dissociation and the CO adsorption to accelerate the hydrogenation to *COH. The highly adaptable metal-support interface of Cu-Ti4O7 enables a direct asymmetrical C-C coupling between *CO on Cu and *COH on Ti4O7, which significantly lowers the reaction energy barrier for C2+ products formation. Additionally, the excellent electroconductivity of Ti4O7 benefits the reaction charge transfer through robust Cu/Ti4O7 interface for minimizing the energy loss. Thus, the optimized 20Cu-Ti4O7 catalyst exhibits an impressive selectivity of 96.4% and ultrahigh energy efficiency of 45.1% for multi-carbon products, along with a remarkable partial current density of 432.6 mA cm-2. Our study underscores a novel C-C coupling strategy between Cu and the support material, advancing the development of Cu-supported catalysts for highly efficient electroreduction of carbon monoxide.

Establishing Non‐stoichiometric Ti4O7 Assisted Asymmetrical C‐C Coupling for Highly Energy‐Efficient Electroreduction of Carbon Monoxide

Exploring an appropriate support material for Cu‐based electrocatalyst is conducive for stably producing multi‐carbon chemicals from electroreduction of carbon monoxide. However, the insufficient metal‐support adaptability and low conductivity of the support would hinder the C‐C coupling capacity and energy efficiency. Herein, non‐stoichiometric Ti4O7 was incorporated into Cu electrocatalysts (Cu‐Ti4O7), and served as a highly conductive and stable support for highly energy‐efficient electrochemical conversion of CO. The abundant oxygen vacancies originated from ordered lattice defects in Ti4O7 facilitate the water dissociation and the CO adsorption to accelerate the hydrogenation to *COH. The highly adaptable metal‐support interface of Cu‐Ti4O7 enables a direct asymmetrical C‐C coupling between *CO on Cu and *COH on Ti4O7, which significantly lowers the reaction energy barrier for C2+ products formation. Additionally, the excellent electroconductivity of Ti4O7 benefits the reaction charge transfer through robust Cu/Ti4O7 interface for minimizing the energy loss. Thus, the optimized 20Cu‐Ti4O7 catalyst exhibits an impressive selectivity of 96.4% and ultrahigh energy efficiency of 45.1% for multi‐carbon products, along with a remarkable partial current density of 432.6 mA cm‐2. Our study underscores a novel C‐C coupling strategy between Cu and the support material, advancing the development of Cu‐supported catalysts for highly efficient electroreduction of carbon monoxide.

Steering the Selectivity of CORR from Acetate to Ethanol via Tailoring the Thermodynamic Activity of Water

AbstractThe electrochemical conversion of carbon monoxide (CO) into oxygenated C2+ products at high rates and selectivity offers a promising approach for the two‐step conversion of carbon dioxide (CO2). However, a major drawback of the CO electrochemical reduction in alkaline electrolyte is the preference for the acetate pathway over the more valuable ethanol pathway. Recent research has shed light on the significant impact of thermodynamic water activity on the electrochemical CO2 reduction reaction pathways, but less is understood for the electrochemical reduction of CO. In this study, we investigated how the water activity at the electrified interface can be enhanced to adjust the selectivity between acetate and ethanol. We employed an ionomer modifier to lower the local concentration of alkali ions (via Donnan exclusion), successfully enhancing ethanol production while suppressing acetate formation. We observed a remarkable improvement in the Faradaic efficiency of ethanol and alcohol (i. e. ethanol, propanol etc), which reached 42.5 % and 55.1 %, respectively, at a current density of 700 mA cm−2. The partial current densities of ethanol and alcohol reached 698 and 942 mA cm−2 at 2000 mA cm−2. Furthermore, we achieved a 3.7‐fold increase in the ethanol/acetate ratio, providing clear evidence of our successful modulation of product selectivity.

A facile double-signal ratiometric sensor of creatinine based on silver nanoparticles/thionine acetate/Mxenes with intrinsic self-calibration property

In this work, a ratiometric double signals electrochemical sensing platform was constructed for creatinine (Cre) analysis employing silver nanoparticles (AgNPs)@ MXenes/thionine acetate (THAT) composites. The synthesis of MXenes/THAT composites was utilized to modify on the surface of a screen-printed electrode (SPE) via dripping coating, followed by the electro-deposition of AgNPs. While the anodic current of the AgNPs decreased in the presence of Cre due to the competive reaction for forming metal complexes, the current of THAT remained invariant, which attained a ratiometric response. Under optimized conditions, the response current ratio (IAg/ITHAT) decreases while the concentration of Cre increased linearly between 0 ∼ 1.2 mM, with 0.01 μM as a adaptive detection limit. It provided a new sensing platforming for employing double-signals nanostructures with remarkable stability and sensitivity to design ratiometic sensors for analysis of Cre in human urine samples with real-time.

Harnessing in-situ oxidation of nanostructured mxene to modulate the electronic structure for improved selectivity for electrochemical carbon dioxide reduction

The electrochemical CO2 reduction reaction (CO2RR) is a promising approach to valorizing CO2. Ti3C2TX as a support material has received significant interest in enhancing CO2RR performance for tuning the electronic structure. However, there has been relatively less focus on changes to the Ti3C2TX electronic structure induced by loading catalysts onto the Ti3C2TX. Because Ti3C2TX has an intrinsic activity for both CO2RR and the competitive hydrogen evolution reaction (HER), electronic structure changes can affect the balance between CO2RR and HER selectivity. Therefore, tuning the electronic structure of Ti3C2TX can control the competition between CO2RR and HER and tune the selectivity and activity. Herein, we report that Ti3C2TX’s electronic structure can be tuned by the Ag+ loading method via redox interactions, tuning the reaction selectivity and activity for CO2RR. To illustrate this effect, we compare the CO2RR performance of in-situ formed Ag nanoparticles (NPs) on Ti3C2TX (0.9Ag-IS-Ti3C2TX) with physically mixed Ag NPs and Ti3C2TX (0.9Ag/P/Ti3C2TX). Here, ‘0.9’ refers to the molar ratio between Ag precursor and Ti3C2Tx, and ‘IS’ vs. ‘P’ refers to in-situ formed vs. physically mixed Ag NPs. 0.9Ag-IS-Ti3C2TX demonstrates a higher oxidation state for Ti and a higher proportion of Ti-O bonds than 0.9Ag/P/Ti3C2TX. Compared to 0.9Ag/P/Ti3C2TX, 0.9Ag-IS-Ti3C2TX exhibits higher CO Faradaic efficiency (FE), rising from 8.1 % with a partial current density of −2.0 mA cm−2 to 49.6 % with a partial current density of −20.1 mA cm−2 at −1.4 V vs. RHE (reversible hydrogen electrode). To harness this effect, we demonstrate control over the CO: H2 ratio of syngas formed from CO2RR over our Ti3C2TX-supported catalysts. Further electrochemical anodic oxidation experiments reveal the critical oxidation potential of Ti3C2TX (0.8 V vs. RHE) and show that HER can be partially suppressed by partial oxidation of Ti3C2TX. This work highlights the importance of considering the changes in Ti3C2TX (and other) supports when supporting catalysts for CO2RR and other electrochemical reactions.

Bi‐Doped In2O3 Nanofiber for Efficient Electrocatalytic CO2 Reduction

AbstractElectrocatalytic carbon dioxide reduction reaction (CO2RR) to formic acid (HCOOH) is attracted for superfluous CO2 removal and HCOOH production under ambient conditions. Indium‐based catalysts has considered as a good candidate material for CO2RR to HCOOH due to their environmentally friendly features. However, the catalytic efficiency is limited by the poor HCOOH Faradaic efficiency (FE) and high reaction overpotential of electrocatalyst, and the activity and stability of indium‐based catalysts are unsatisfactory, especially in industrial current density that is critical for commercialization. Herein, a fiber Bi‐doped In2O3 was synthesized through electrospinning method, and it demonstrate a FEHCOOH of 88.2% at −1.5 V versus RHE (reversible hydrogen electrode) with partial current density of −21.8 mA cm−2 in H type cell. Specially, the Bi‐In electrocatalyst also reach the industrial current density standard, which can work at −400 mA cm−2 current density with FEHCOOH of 92.7% (yield of HCOOH is 6.9 mmol h−1) in home‐made Flow cell. Importantly, Bi‐In shows 24 h long‐term stability test in −300 mA cm−2. The improvement catalytic activity of Bi‐In catalyst is ascribed to the optimized electronic structure of In site, and the reduced work function value of Bi‐In is beneficial for reducing the formation energy of the key *OCHO intermediates.