Combination Of Cu Research Articles

Front Cover: Synergistic One‐pot Tandem Combination of Cu and Proline Catalysis: Stereodivergent Synthesis of Chiral Aldols from Primary Alcohols (ChemCatChem 15/2024)

Front Cover: Synergistic One‐pot Tandem Combination of Cu and Proline Catalysis: Stereodivergent Synthesis of Chiral Aldols from Primary Alcohols (ChemCatChem 15/2024)

Vacancy Ordering in Ultrathin Copper Oxide Films on Cu(111).

Oxide thin films grown on metal surfaces have wide applications in catalysis and beyond owing to their unique surface structures compared to their bulk counterparts. Despite extensive studies, the atomic structures of copper surface oxides on Cu(111), commonly referred to as "44" and "29", have remained elusive. In this work, we demonstrated an approach for the structural determination of oxide surfaces using element-specific scanning tunneling microscopy (STM) imaging enhanced by functionalized tips. This approach enabled us to resolve the atomic structures of "44" and "29" surface oxides, which were further corroborated by noncontact atomic force microscopy (nc-AFM) measurements and Monte Carlo (MC) simulations. The stoichiometry of the "44" and "29" frameworks was identified as Cu23O16 and Cu16O11, respectively. Contrary to the conventional hypothesis, we observed ordered Cu vacancies within the "44" structure manifesting as peanut-shaped cavities in the hexagonal lattice. Similarly, a combination of Cu and O vacancies within the "29" structure leads to bean-shaped cavities within the pentagonal lattice. Our study has thus resolved the decades-long controversy on the atomic structures of "44" and "29" surface oxides, advancing our understanding of copper oxidation processes and introducing a robust framework for the analysis of complex oxide surfaces.

Combination of Cu and Zn on ZIF structure for efficient degradation of basic fuchsin in aqueous solution

Combination of Cu and Zn on ZIF structure for efficient degradation of basic fuchsin in aqueous solution

Cu-BTC-derived Cu@C as nano-heater embedded in 3D g-C3N4 for photothermal-coupled photocatalytic CO2 reduction under full-spectrum solar irradiation

This study developed a novel Cu@C/NCN-T composite for efficient photothermal catalytic CO2 reduction. The composite, consisting of carbon-coated Cu (Cu@C) derived from Cu-BTC embedded in three-dimensional graphitic carbon nitride (NCN-T), was immobilized on the surface of carbonized wood (C-wood) floating on water, creating a triphase system (CO2, H2O, and catalyst). The optimized composite demonstrated remarkable CO2 photothermal reduction performance, achieving a rate of 31.3 μmol·g−1·h−1. This performance surpassed that of pure NCN-T and Cu@C by 1.6 and 3.8 times, respectively. The combination of Cu and carbon materials endowed Cu@C/NCN-T with excellent light-absorption properties, resulting in a photothermal effect that elevated the surface temperature and facilitated the catalytic reaction. Furthermore, the Schottky junction formed between Cu@C and NCN-T promoted the separation of electron-hole pairs, with Cu@C acting as charge channels. A charge transfer mechanism was proposed to explain these findings. This catalyst engineering approach holds promise for the development of efficient non-noble metal catalysts for rapid CO2 photothermal reduction.

Synergistic One‐pot Tandem Combination of Cu and Proline Catalysis: Stereodivergent Synthesis of Chiral Aldols from Primary Alcohols

AbstractA new stereodivergent one‐pot tandem protocol, which granted diastereo‐ and enantioselective access to chiral aldols by starting from simple primary alcohols, is presented as a proof‐of‐concept. The synergistic combination of a chemoselective Cu(II)‐catalyzed oxidation of primary alcohols into the corresponding aldehydes (without the expected overoxidation into the corresponding carboxylic acids and using simple aerial O2 as co‐oxidant), followed by a concomitant organocatalyzed enantioselective aldol coupling promoted by the system (S)‐proline/HTBD‐BF4 [TBD=1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene], was achieved after fine‐tuning and compatibilizing the conditions required for the successful performance of both catalytic systems. Here, we demonstrated that selection and pairing of both catalysts needs to be extremely judicious to avoid orthogonality, kinetic, concentration or reciprocal poisoning issues. Refinement of the overall tandem protocol allowed us to design a synergistic and stereodivergent protocol which affords comparable or even better diastereoselective results than the organocatalytic system by itself. Finally, the following key factors (from a sustainable point of view) should be highlighted: i) no external VOC solvents are needed during our one‐pot tandem synthetic protocol (by working under neat conditions); and ii) isolation/purification of any intermediate is not required, thus reducing the chemical waste and energy/time costs, simplifying the practical aspects of our synthetic methodology.

The effect of the combined addition of copper, lithium and sulphur on the formation of Portland cement clinker.

Both copper and lithium act as strong fluxes and lower the temperature of the clinker melt formation. Sulphur promotes the stabilisation of more hydraulically active modification of alite M1. It is expected that this combination could produce an alite clinker at significantly lower temperatures with high quality technological parameters. In this paper, the effect of combined oxides of copper, lithium and sulphur addition on the phase composition and clinker structure of Portland cement was investigated. The reference raw meal was prepared from common cement raw materials. Each of the mentioned oxides was added to the reference raw meal in two different concentrations, and 8 combinations were prepared. Chemically pure compounds (NH4)2SO4, CuO and Li2CO3 were used as a source of these oxides. The raw meals were burned to equilibrium at 1450°C. Their phase composition was determined by X-ray diffraction analysis, the microstructure was monitored by optical microscopy, and the microchemistry of the clinker phases was observed by electron microscopy with EDS analysis. It was found that in samples with high lithium or copper content, there is an increase in belite and free lime at the expense of alite. The combination of Cu + Li has the most negative effect, followed by Li alone and Cu alone. The higher SO3 content slightly offsets this negative effect.

Ternary nanofluids due to moving wedge with strong magnetic field and convective condition

The control of temperature distribution and management of heat energy are key problems in an industry. In this study, free convective flow with ternary nanoparticles (Cu, Ag, MgO) was equipped to analyze the impact on magnetic field and thermal radiation through a moving wedge surface. This volumetric concentration by Cu, Ag and MgO nanoparticles is selected by the most 4% to prevent the instability on the nanofluid. A set of applicable modifications was expressed as a change in the nonlinear partial differential equations and the nonlinear ordinary differential equations and it was undertaken mathematically for applying bvp4c on MATLAB package. These outcomes on ternary nanoparticles (Cu–Ag–MgO/blood), and hybrid nanoparticles (Cu–Ag/blood) and copper (Cu) nanoparticles had again correlated. The outcomes display that connecting Cu, Ag and MgO nanofluid raises the drug friction to 3.9% than the hybrid nanofluid. Also, the combination of Cu and Ag nanofluid increases skin friction by 19.58% than Cu nanofluid. This analysis was particularly useful in drug transportation and biomedical study.

Interfacial reactions in Ta/304L and Ta/Cu/304L composites during single-shot explosive welding and post-processing annealing

This work presents a study of recent advances in the understanding of the mechanism controlling chemical composition and the microstructure of reaction regions in a Ta/304L steel composite with and without Cu interlayers fabricated by explosive welding, both during composite formation and post-processing annealing. The microstructure of solidified melt regions (SMR) were characterized using scanning and transmission electron microscopy while phase composition by X-ray synchrotron radiation. It was found that SMR in Ta/304L plates are composed of ultra-fine-grained microstructure with a varied chemical compositions, containing elements from both combined sheets. In Ta/Cu/304L composites the melted regions located close to Ta/Cu interface composed only of a combination of Cu and Ta (small dendrites and ultra-fine grains), when the areas near the Cu/304L interface consisted of nano-grains with a more diverse chemical composition, containing elements from both sheets. No significant effect of the annealing (under the applied temperature of 700°C and for times up to 103 h) on changes in the microstructure of the SMR was observed in both plates.

Copper-Catalyzed Asymmetric Allylation of N-Aryl Aldimines.

The copper-catalyzed enantioselective allylation reaction of N-aryl aldimines has been developed using a combination of Cu(OAc)2 and SPINOL-based phosphonamidite. This protocol significantly broadens the substrate scope, such that imines bearing various ortho-substituents on the N-aryl were converted smoothly into homoallylic amines in up to 99% yield and 98% ee. Taking advantage of the diversity of the N-aryl motif, three kinds of N-heterocyclic compounds were constructed, respectively, from the corresponding homoallylic amines in merely one step.

Unraveling assemblage of microbial community dwelling in Dabaoshan As/Pb/Zn mine-impacted area: A typical mountain mining area of South China

Microbial community assemblage includes microorganisms from the three domains including Bacteria, Archaea, and Eukarya (Fungi), which play a crucial role in geochemical cycles of metal(loid)s in mine tailings. Mine tailings harbor vast proportions of metal(loid)s, representing a unique source of co-contamination of metal(loid)s that threaten the environment. The elucidation of the assembly patterns of microbial communities in mining-impacted ecospheres has received little attention. To decipher the microbial community assembly processes, the microbial communities from the five sites of the Dabaoshan mine-impacted area were profiled by the MiSeq sequencing of 16S rRNA (Bacteria and Archaea) genes and internal transcribed spacers (Fungi). Results indicated that the coexistence of 31 bacterial, 10 fungal, and 3 archaeal phyla, were mainly dominated by Mucilaginibacter, Cladophialophora, and Candidatus Nitrosotalea, respectively. The distribution of microorganisms was controlled by deterministic processes. The combination of Cu, Pb, and Sb was the main factor explaining the structure of microbial communities. Functional predicting analysis of bacteria and archaea based on the phylogenetic investigation of communities by reconstruction of unobserved states analyses revealed that the metabolic pathways related to arsenite transporter, arsenate reductase, and FeS cluster were important for metal detoxification. Furthermore, the ecological guilds (pathogens, symbiotrophs, and saprotrophs) of fungal communities explained 44.5 % of functional prediction. In addition, metal-induced oxidative stress may be alleviated by antioxidant enzymes of fungi communities, such as catalase. Such information provides new insights into the microbial assembly rules in co-contaminated sites.

Selective N‐Methylation of N‐Methylaniline with CO2 and H2 over Cu/In2O3 Catalyst†

Comprehensive SummaryN‐Methylation of amines with CO2 and H2 is a potential approach for CO2 utilization because N‐methylated amines can be used as solvents and organic intermediates. In2O3‐supported Cu (Cu/In2O3) acts as an effective heterogeneous catalyst for N‐methylation reaction of N‐methylaniline (MA) with CO2 and H2, showing higher N,N‐dimethylaniline (DMA) selectivity than other supported Cu catalysts. On one hand, the dispersion of Cu can be improved by the defective In2O3 support. On the other hand, In2O3 support is active in the dissociative adsorption of CO2 through C—O bond breaking. In addition, the H2 dissociation ability of In2O3 can also be enhanced by Cu. The combination of Cu and In2O3 is effective in the activation of CO2, the adsorption of intermediate N‐methylformanilide (MFA), the hydrogenation of MFA to DMA and the prohibition of C—N bond cleavage side reactions, thereby enhancing the reaction rate of MA conversion and the selectivity to DMA.

Bimetallic oxide Cu–Fe3O4 nanoclusters with multiple enzymatic activities for wound infection treatment and wound healing

Infections and oxidative stress complicate wound healing. In recent years, nanomaterials with natural enzymatic activities have enabled the development of new antibacterial pathways. In this study, Cu–Fe3O4 nanoclusters with multienzyme properties were synthesized. Interestingly, they exhibited activity similar to that of horseradish peroxidase (POD) in acidic environments but their functions resembled superoxide dismutase and catalase in neutral or weakly alkaline environments. In vitro studies have demonstrated the good free-radical scavenging activity of Cu–Fe3O4 nanoclusters in a neutral environment. Under acidic conditions, Cu–Fe3O4 nanoclusters combined with H2O2 demonstrated good antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli). The combination of Cu–Fe3O4 and H2O2 was found to be effective in preventing MRSA infections and promoting wound healing in animal models. RNA sequencing (RNA-seq) technology revealed that chemodynamic therapy (CDT) using nanoparticles can interfere with metabolic processes such as galactose metabolism in MRSA bacteria, destroy the transport system on the surface of MRSA, and affect quorum sensing to hinder the formation of biofilms, thus achieving effective antibacterial efficacy. The use of Cu–Fe3O4 nanoclusters as a novel class of multi-catalytically active nanozymes in the anti-infection of disease-causing pathogens and wound healing has significant potential. Statement of significanceCu–Fe3O4 nanoclusters with multienzyme properties were successfully prepared by a solvothermal method. Cu–Fe3O4 nanoclusters exhibited horseradish peroxidase (POD)-like activity in acidic environments and also showed synergistic effects similar to superoxide dismutase peroxidase in neutral or weakly basic environments. More importantly, these Cu–Fe3O4 nanoclusters showed high biosafety with no apparent in vivo toxicity. Chemodynamic therapy (CDT) using Cu–Fe3O4 nanoclusters was revealed by RNA sequencing (RNA-Seq) technology to interfere with the metabolic processes of MRSA bacteria, such as galactose metabolism, disrupt the MRSA surface transport system, and impede biofilm formation, resulting in effective antibacterial efficacy. The use of Cu–Fe3O4 nanoclusters for anti-infection and wound healing of pathogenic pathogens has significant potential as a novel class of multi-catalytic active nanoclusters.

Coal gangue geopolymers as sustainable and cost-effective adsorbents for efficient removal of Cu (II)

Coal gangue geopolymers (GP) were employed to eliminate Cu (II) as an economical absorber. This study explores the feasibility of employing coal gangue geopolymers (GP) to be an economical absorber with a function of eliminating Cu (II). The results showed that GP is a mesoporous structure, which pore size distribution is around 5.60 nm. The optimal adsorption capacity of Cu (II) was achieved when the ratio n(SiO2)/n(Na2O) was 1.2. Cu (II) adsorption capacity of GP may achieve a maximum of 72.3 mg/g. Silicon and aluminum hydroxide groups of GP facilitated strong interactions and effective trapping of Cu (II). Data analysis discovered that the adsorption procedure in examinations followed a pseudo-second-order kinetic model, with the Langmuir model providing the best appropriate to the adsorption isotherm data. These confirm that charge and chemisorption simultaneously appeared in the spontaneous Cu (II) adsorption on GP. The intra-particle diffusion model (IPD) and Boyd models supported by observation that positive relationships result in initial Cu (II) adsorption onto the outer layer of GP, followed by subsequent diffusion into internal pores. Internal and external diffusion processes jointly dominate the Cu (II) adsorption rate. Furthermore, the adsorption-related characteristics of a combination of Cu (II) and Cr (VI) demonstrated that GP effectively removes Cr (VI) without compromising its adsorption performance for Cu (II), without any discernible competition or synergy between the two. Notably, the GP could be reused for five times, and Cu (II) removal rate is 80.88%, indicating the possibility of its application as an effective, sustainable Cu (II) removal absorbent.

Defects induced the bilayer graphene-copper hybrid and its effect on mechanical properties of graphene reinforced copper matrix composites

Graphene/Cu composites have shown great potential in the fields of mechanical engineering, electronic devices and so on. In this study, the impacts of vacancies on the interlayer interaction of bilayer graphene (BLG) and the resultant influence of graphene interlayer bonding on the interfacial bonding, tensile strength, and slipping mechanism of the graphene/Cu composites are comprehensively investigated based on first-principles calculations. It was revealed that clustering of cross-layer vacancies (CV) can initiate the formation of distinct hybrid types (sp2 hybrid, sp3 hybrid) of interlayer bonds, resulting in enhanced interlayer bonding of BLG. Unlike the van der Waals interaction between graphene and Cu, vacancies cause the Cu atoms on the surfaces to be embedded in the BLG, forming the graphene-copper hybrid that can improve the combination of Cu and graphene. The notable hybridization between the 2p orbitals of the unsaturated C atoms neighboring the vacancies and the 4s, 3d orbitals of the Cu atoms on the surfaces drives this effect. BLG with interlayer bonds can substantially improve the interfacial bonding and mechanical properties of the composites. This research provides a novel outlook for the interface engineering research and innovative development of graphene/Cu composites by regulating the interlayer bonding of grapheme.

LaFe13−xSixHz magnetocaloric composites obtained via room temperature processing

LaFe13−xSixHz alloys are promising candidates for room temperature magnetic refrigeration, but their brittle behaviour hinders their shaping into magnetocaloric devices. Metal bonding of LaFe13−xSixHz particles has been performed to overcome this issue, but the fabrication processes reported so far involve the exposure of LaFe13−xSixHz particles to temperatures where dehydrogenation occurs, which deteriorates their magnetocaloric properties. This work proposes two processing routes (P1 and P2) which were carried out entirely at room temperature, hence avoiding dehydrogenation. Route P1 consisted of binding LaFe13−xSixHz particles with Sn, while in route P2 two binders were combined: Sn and Cu. Final average porosities were equal to 12.8 % (P1) and 12.1 % (P2), which are comparable to what has been reported for hot processed composites, and differential scanning calorimetry analyses indicated that dehydrogenation did not occur during processing, an improvement in comparison to hot processing. Complementarily, the mechanical behaviour of the composites was investigated via Weibull analysis. Characteristic strengths of 49.9 MPa (P1) and 60.7 MPa (P2) were found under uniaxial compression, showing that the combination of Cu and Sn as binders promoted higher strength. Weibull moduli of 10.9 (P1) and 8.8 (P2) were identified, which are greater than what has been previously reported for a bulk alloy, indicating that embedding LaFe13−xSixHz particles in a metallic matrix led to a less brittle-like behaviour.

CuO[sbnd]Co3O4 nanoparticle catalysts rich in oxygen vacancies toward upgrading anodic electro-oxidation of glycerol

The replacement of the anodic oxygen evolution reaction in water electrolysis with the glycerol electro-oxidation reaction not only lowers the anodic potential and enhances hydrogen production efficiency at the cathode, but also yields valuable chemicals at the anode, thereby improving overall economic viability. The development of efficient and cost-effective catalysts for the electro-oxidation reaction of glycerol remains a significant challenge. Here, CuOCo3O4 loaded on nickel foam (CuOCo3O4/NF) is in situ prepared by solvothermal methods. The analysis of scanning electron microscopy reveals that CuOCo3O4 consists of micrometer-scale spherical particles, which are further assembled by even smaller nano-scale particles. The combination of Cu and Co in the catalyst induces lattice strain, as characterized by Raman and X-ray photoelectron spectroscopy, leading to an increased generation of oxygen vacancies. The electrochemical tests demonstrate that CuOCo3O4/NF exhibits superior electrocatalytic activity at a Cu:Co molar ratio of 1:1, requiring only 1.13 V vs RHE to achieve a current density of 10 mA cm−2. This performance surpasses other ratios as well as monometallic CuO and Co3O4. The CuOCo3O4/NF║CuOCo3O4/NF two-electrode system requires 1.46 V to achieve a current density of 50 mA cm −2 and exhibits excellent stability during a 12 h testing period. The electrolysis products consist of formic acid, glycolic acid, and glyceric acid, with the highest selectivity recorded at 90.3 % for formic acid. The high electrocatalytic performance of the CuOCo3O4/NF catalyst can be attributed to its spherical structure and the presence of oxygen vacancies.

Single and joint toxic effects of waterborne exposure to copper and cadmium on Coregonus ussuriensis Berg.

Heavy metal contamination severely affects the aquatic environment and organisms. Copper (Cu) and cadmium (Cd) are two of the most common heavy metal contaminants that impair the survival, development, and reproduction of aquatic organisms. With the growth of agriculture and industry, there is a possibility of heavy metal pollution in Coregonus ussuriensis Berg's water source. However, there are no published studies on the toxicity to C. ussuriensis. Acute toxicity experiments in C. ussuriensis revealed the 96-h median lethal concentrations of copper and cadmium to be 0.492 mg·L-1 (95% confidence interval: 0.452-0.529) and 1.548 mg·L-1 (95% confidence interval: 1.434-1.657), respectively, and safe concentrations of 4.92 µg·L-1 and 15.48 µg·L-1, respectively. C. ussuriensis was then treated for 96 h with Cu (20% of 96 h LC50), Cd (20% of 96 h LC50), and a combination of Cu and Cd (20% of Cu 96 h LC50 + 20% of Cd 96 h LC50). The histological damage caused by the three different exposure modes to the liver and gills of C. ussuriensis was verified using hematoxylin and eosin staining. All three exposure modes caused different degrees of vacuolization, nuclear consolidation, and necrosis in the liver tissue of C. ussuriensis and edema, hyperplasia, laminar fusion, and epithelial elevation in the gill tissue compared with the reference group. The severity of the damage increased with increasing exposure time. Anti-oxidant activity in the gill and liver tissues were measured using enzyme activity assay kits to reflect oxidative stress induced by copper and cadmium exposure alone and in combination. The enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH) were substantially higher than those in the reference groups. However, the activities of the enzymes decreased with increasing exposure time. Malondialdehyde (MDA) activity significantly increased during exposure in relation to that in the reference group. Analysis of immune gene expression in C. ussuriensis gill and liver tissues was executed using real-time inverse transcript polymerase chain response (RT-PCR). The expression levels of the pro-inflammatory cytokines interleukin one beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were positively correlated with exposure time and were significantly upregulated with increasing exposure time. Metallothionein (MT) gene expression levels were significantly upregulated in the short term after exposure compared to the reference group but decreased with increasing exposure time. Our results indicate that exposure to aqueous copper and cadmium solutions, either alone or in combination, causes histopathological damage, oxidative stress, and immunotoxicity in C. ussuriensis gill and liver tissue. This study investigated the toxic effects of copper and cadmium on C. ussuriensis to facilitate the monitoring of heavy metals in water sources for healthy aquaculture.

Winning Combination of Cu and Fe Oxide Clusters with an Alumina Support for Low-Temperature Catalytic Oxidation of Volatile Organic Compounds.

A γ-alumina support functionalized with transition metals is one of the most widely used industrial catalysts for the total oxidation of volatile organic compounds (VOCs) as air pollutants at higher temperatures (280-450 °C). By rational design of a bimetal CuFe-γ-alumina catalyst, synthesized from a dawsonite alumina precursor, the activity in total oxidation of toluene as a model VOC at a lower temperature (200-380 °C) is achieved. A fundamental understanding of the catalyst and the reaction mechanism is elucidated by advanced microscopic and spectroscopic characterizations as well as by temperature-programmed surface techniques. The nature of the metal-support bonding and the optimal abundance between Cu-O-Al and Fe-O-Al species in the catalysts leads to synergistic catalytic activity promoted by small amounts of iron (Fe/Al = 0.005). The change in the metal oxide-cluster alumina interface is related to the nature of the surfaces to which the Cu atoms attach. In the most active catalyst, the CuO6 octahedra are attached to 4 Al atoms, while in the less active catalyst, they are attached to only 3 Al atoms. The oxidation of toluene occurs via the Langmuir-Hinshelwood mechanism. The presented material introduces a prospective family of low-cost and scalable oxidation catalysts with superior efficiency at lower temperatures.

Semisolid-Liquid Fabrication of Cu–Cr Pseudobinary Alloy by Laser-Directed Energy Deposition

Copper–Chromium (Cu–Cr) pseudobinary alloys are promising materials for electrical application. Nevertheless, their fabrication remains limited by traditional techniques, which are not suitable for manufacturing homogeneous Cu–Cr alloys with uniformly distributed elements. Recently, semisolid-liquid manufacturing method has emerged as a promising technique route to fabricate Cu–Cr alloys. In this work, the laser-directed energy deposition (L-DED) as one of the laser additive manufacturing (LAM) technology, was successfully introduced for semisolid-liquid fabricating the homogeneous Cu–30 mass%Cr alloys. The obtained Cu–Cr alloys are constituted by fully melted Cu metallurgically combined with semisolid-liquid Cr. The close combination of Cu and Cr is benefit to improve the electrical conductivity of the alloy.

Cu/CdCO3 catalysts for efficient electrochemical CO2 reduction over the wide potential window

High efficiency and low-cost catalyst-driven electrocatalytic CO2 reduction to CO production are of great significance for energy storage and development. The severe competitive hydrogen evolution reaction occurs at large negative potential window limits the achievement of the target product from CO2 at high efficiency. Here, we successfully prepared Cux/CdCO3 composite catalyst rich in interfaces, in which achieved high CO Faraday efficiency exceeded 90% in a wide potential window of 700 mV and highest value up to 97.9% at −0.90 V vs. RHE. The excellent performance can be ascribed to the positive contribution of Cux/CdCO3, which maintains a suitable high local pH value during electrochemical reduction, thus inhibiting the competitive hydrogen evolution reaction. Moreover, the compact structure between Cu and CdCO3 ensures fast electron transfer both inside catalysts and interface, thus speeding up the reaction kinetics of CO2 to CO conversion. Theoretically calculations further prove that the combination of Cu and CdCO3 provides the well-defined electronic structure for intermediates adsorption, significantly reducing the reaction barrier for the formation of CO. This work provides new insights into the design of efficient electrochemical CO2 reduction catalysts for inhibiting hydrogen evolution by adjusting the local pH effect.