PdCu Alloy Research Articles

Recycling copper wire waste into active Cu-based catalysts for value-added chemicals production via CO2 electrochemical reduction

The CO2 electroreduction reaction (CO2RR) is a method for producing value-added compounds from CO2. This study aimed to use copper from wiring waste to create Cu-based catalysts on Vulcan XC-72R carbon for converting CO2 into valuable chemicals. Copper nanopowder with an average crystallite size of 27 nm derived from the wiring waste solution was utilized as the starting material for mono and bimetallic catalysts preparation. During the bimetallic PdCu/C catalyst synthesis, a galvanic displacement reaction between Pd and Cu occurred, resulting in the formation of PdCu alloy and a reduction in the copper crystallite size. The inclusion of Pd on Cu/C in CO2RR decreased the onset potentials for C1 and C2 chemical production. The yields of methanol, formic acid, and formaldehyde products were generally increased as the Pd:Cu ratio increased. The 1:2-PdCu/C exhibited the smallest crystallite size and an onset potential of less than −1.0 V, resulting in the highest Faradaic efficiency of the products. This catalyst converted CO2 into formic acid (FE = 71.5 %) at a potential of −0.8 V and methanol (FE = 65.4 %) at −0.5 V. The catalyst’s stability was demonstrated for more than 6000 s at current densities of approximately 2 mA /mgcatalyst.

Entropy-Derived Synthesis of the CuPd Sub-1nm Alloy for CO2-to-acetate Electroreduction.

Bimetallic alloys exhibit remarkable properties in catalysis and energy storage, while their precise synthesis at the subnanoscale remains a formidable challenge due to their immiscible nature in thermodynamics. In this study, we engineer an atomically dispersed CuPd alloy with an average size of 1.5 nm loaded on CuO and phosphomolybdic acid (PMA) coassembly subnanosheets (CuO-PMA SNSs). Driven by the high vibrational entropy, Cu atoms could escape from CuO supports and bond with adjacent Pd single atoms, leading to the in situ formation of CuPd alloys. Furthermore, this strategy can also be utilized for synthesizing the ZnPt alloy with an average size of 1 nm, thereby providing a general pathway for the design of immiscible subnanoalloys. The fully exposed Cu-Pd pairs in CuPd subnanoalloys significantly enhance the adsorption and coverage of surface *CO during the electrochemical reduction of CO2, thereby leading to enhanced stability of ethenone intermediates and facilitating the production of C2 compounds. The resulting CuPd subnanoalloy exhibits a remarkable Faradaic efficiency of 46.5 ± 2.1% for CO2-to-acetate electroreduction and achieves a high acetate productivity of 99 ± 2.8 μmol cm-2 at -0.7 V versus RHE.

One-pot synthesis of porous carbon nanospheres supported CuPd alloy catalysts for the hydrogenation-dechlorination of 2,3,6-trichloropyridine

Hydrogenation-dechlorination to produce 2,3-dichloropyridine is important for the next-generation pesticides. In this work, we successfully synthesized porous carbon nanospheres supported CuPd alloy nanoparticles via a simple and efficient one-pot strategy. Furthermore, by adjusting the Cu/Pd ratio and carbonization temperature, the obtained Cu2Pd1@PCNs-500-H2O2 showed the highly catalytic activity for the hydrogenation-dechlorination of 2,3,6-trichloropyridine with a conversion rate of 70.1 % and selectivity of 71.2 %. The catalyst showed outstanding catalysis performance even after five cycles. This simple and rapid one-pot strategy provides a new approach for the large-scale synthesis of efficient heterogeneous catalysts and offers an effective solution for reducing the high costs associated with precious metals.

Recent Advances in Urea Electrocatalysis: Applications, Materials and Mechanisms†

Comprehensive SummaryUrea plays a vital role in human society, which has various applications in organic synthesis, medicine, materials chemistry, and other fields. Conventional industrial urea production process is energy−intensive and environmentally damaging. Recently, electrosynthesis offers a greener alternative to efficient urea synthesis involving coupling CO2 and nitrogen sources at ambient conditions, which affords an achievable way for diminishing the energy consumption and CO2 emissions. Additionally, urea electrolysis, namely the electrocatalytic urea oxidation reaction (UOR), is another emerging approach very recently. When coupling with hydrogen evolution reaction, the UOR route potentially utilizes 93% less energy than water electrolysis. Although there have been many individual reviews discussing urea electrosynthesis and urea electrooxidation, there is a critical need for a comprehensive review on urea electrocatalysis. The review will serve as a valuable reference for the design of advanced electrocatalysts to enhance the electrochemical urea electrocatalysis performance. In the review, we present a thorough review on two aspects: the electrocatalytic urea synthesis and urea oxidation reaction. We summarize in turn the recently reported catalyst materials, multiple catalysis mechanisms and catalyst design principles for electrocatalytic urea synthesis and urea electrolysis. Finally, major challenges and opportunities are also proposed to inspire further development of urea electrocatalysis technology. Key ScientistsFor urea electrosynthesis, Furuya et al. firstly investigated the electrochemical coreduction of CO2 and NO3−/NO2− using gas‐diffusion electrodes in 1995. Then, Wang et al. effectively achieved C—N bond formation and urea synthesis on PdCu alloy nanoparticles in 2020. Shortly, Yan and Yu et al. proposed the formation of *CO2NO2 from *NO2 and *CO2 intermediates at early stage on In(OH)3 electrocatalyst in 2021, and employed defect engineering strategy to facilitate the *CO2NH2 protonation in 2022. Amal et al. Investigated the role that Cu‐N‐C coordination plays for both the CO2RR and NO3RR. After that, Zhang's group developed In‐based electrocatalysts with artificial frustrated Lewis pairs for urea, and they offered a systematic screening approach for catalyst design in urea electrosynthesis in 2023. And sargent et al. reported a strategy that increased selectivity to urea using a hybrid catalyst.For urea electrooxidation, Stevenson et al. investigated the effect of Sr substitution toward the urea oxidation reaction. Wang et al. provided insights into the urea electrooxidation process using a β‐Ni(OH)2 electrode and Qiao et al. elucidated a two‐stage reaction pathway for UOR in 2021.

Alloying effect-triggered electron polarization in PdCu metallene for simultaneous electrocatalytic upcycling of nitrate and polyethylene terephthalate to value-added chemicals

Electrocatalytic convert nitrate wastewater and discarded polyethylene terephthalate (PET) into high-value chemicals is an effective approach to addressing environmental pollution while generating economic benefits. To achieve this vision, herein, PdCu alloy metallene grown on Ni foam (PdCuene/NF) was synthesized via a one-step solvothermal method and directly used for anodic ethylene glycol oxidation reaction (EGOR), while an additional oxidation-electroreduction treatment was conducted to further convert it into reconstructed PdCuene/NF (r-PdCuene/NF) for cathodic nitrate reduction reaction (NO3RR). With the synergism of metallene array structure and alloying effect, the cathodic r-PdCuene/NF showed an enhanced nitrate-to-ammonia activity with a maximum Faradaic efficiency (FE) of 91.59 ± 2.79 %, while the anodic PdCuene/NF could effectively convert EG into glycolic acid (maximum FE: 92.12 % ± 0.26 %). The coupling of nitrate reduction with PET-derived EG oxidation based on these two materials allowed the simultaneous production of ammonia and glycolic acid with high FEs (>94 %).

Enhancing Localized Electron Density over Pd1.4Cu Decorated Oxygen Defective TiO2-x Nanoarray for Electrocatalytic Nitrite Reduction to Ammonia.

Electrocatalytic nitrite (NO2 -) reduction to ammonia (NH3) is a promising method for reducing pollution and aiding industrial production. However, progress is limited by the lack of efficient selective catalysts and ambiguous catalytic mechanisms. This study explores the loading of PdCu alloy onto oxygen defective TiO2-x, resulting in a significant increase in NH3 yield (from 70.6 to 366.4µmolcm-2h-1 at -0.6V vs reversible hydrogen electrode) by modulating localized electron density. In situ and operando studies illustrate that the reduction of NO2 - to NH3 involves gradual deoxygenation and hydrogenation. The process also demonstrated excellent selectivity and stability, with long-term durability in cycling and 50h stability tests. Density functional theory (DFT) calculations elucidate that the introduction of PdCu alloys further amplified electron density at oxygen vacancies (Ovs). Additionally, the Ti─O bond is strengthened as the d-band center of the Ti 3d rising after PdCu loading, facilitating the adsorption and activation of *NO2. Moreover, the presence of Ovs and PdCu alloy lowers the energy barriers for deoxygenation and hydrogenation, leading to high yield and selectivity of NH3. This insight of controlling localized electron density offers valuable insights for advancing sustainable NH3 synthesis methods.

Visible light excitation on CuPd/TiN with enhanced chemisorption for catalyzing heck reaction

In this work, we developed plasmonic photocatalyst composed of CuPd alloy nanoparticles supported on TiN, the optimized Cu3Pd2/TiN catalyst shows excellent conversion (>96 %) and selectivity (>99 %) for Heck reaction at 50 °C under visible light irradiation. By in-situ spectroscopic investigations, we find that visible light excitation could achieve stable metallic Cu species on the surface of CuPd alloy nanoparticles, thereby eliminating the inevitable surface oxides of Cu based catalyst. The in-situ formed metallic Cu species under irradiation take advantage of the strong interactions of Cu with visible light, and manifest in the localized surface plasmon resonances (LSPR) photoexcitation. Visible light excitation could further promote the charge transfer between catalytic Pd component and the support TiN, resulting in electron-rich Pd sites on CuPd/TiN. Moreover, light excitation on CuPd/TiN generates strong chemisorption of iodobenzene and styrene, favoring the activation of reactants for Heck reaction. DFT calculations suggest that electron-rich CuPd sites ideally lower the activation energy barrier for the coupling reaction. This work provides valuable insights for mechanistic understanding of plasmonic photocatalysis.

Dual Photoactive Species in CuPd for Light‐switched Homo‐coupling of Alkynes in Anaerobic and Base Free Condition

AbstractVarious ratios of CuPd alloy are loaded on C3N4 and utilized as efficient photocatalyst for the light‐switched homo‐coupling of alkynes in anaerobic and base free condition. For the model phenylacetylene reactant, the light‐irradiation promotes the reaction rate from 36.9 % to 99.9 % and the selectivity of 1,3‐diynes from 0 % to 68.7 %. Different supports, solvents and the induction period of the prepared samples show influence on the activity. The action spectra with different light wavelengths demonstrate that both copper phenylacetylide intermediate formed during the reaction and the localized surface plasmon resonance (LSPR) effect of the copper in CuPd alloy are the photoactive species. Through the control experiments, it confirms that these dual photoactive species and the interface between Cu and Pd are essential for efficient light‐switching reaction pathway.

Ordering Bimetallic Cu-Pd Catalysts onto Orderly Mesoporous SrTiO3-Crystal Nanotubular Networks for Efficient Carbon Dioxide Photoreduction.

Artificial photosynthesis of fuels has garnered significant attention, with SrTiO3 emerging as a potential candidate for photocatalysis due to its exceptional physicochemical properties. However, selectively converting CO2 into fuels with desired reaction products remains a grand challenge. Herein, we design an updated method via an aging strategy based on the electrospinning technique to synthesize a single-crystalline Al-doped SrTiO3 nanotubular networks with self-assembled orderly mesopores, further modified by Cu-Pd alloy. It exhibits both high crystallinity and superior cross-linked mesoporous structures, effectively facilitating charge carrier transfer, photon utilization, and mass transfer, with a remarkable enhancement from 0.025 mmol h-1 m-2 to 1.090 mmol h-1 m-2 in the CO production rate. Meanwhile, the ordered arrangement of Cu and Pd atoms on the (111) surface can promote the rate-determining step (*CO2 to *COOH), which is also responsible for its good activity. The presence of CuO in the reaction confers a significant advantage for CO desorption, leading to a remarkable CO selectivity of 95.54 %. This work highlights new insights into developing advanced heterogeneous photocatalysts.

Rapid synthesis of PdCu nanosheets with enhanced electrocatalytic activity toward polyalcohol oxidation reaction

Reasonable design of Pd-based catalysts with specific composition and morphology is of great importance for promoting the commercial application.of direct alcohol fuel cells (DAFCs). Recently, two-dimension (2D) with high density of defects and massive low-coordinated surface atom has become research highlights in the field of catalysis. Herein, we report a wet chemical method for synthesizing PdCu nanosheets with abundant wrinkles. The ultrathin two-dimensional structure endows catalysts plentiful catalytic active sites and large specific surface area, improving atomic utilization efficiency. The formation of bimetallic PdCu alloy structure leads to the adjustment of Pd electronic structure, resulting in lattice compression effect. Benefitting from the structural and compositional characteristics, PdCu nanosheets (NSs) exhibits excellent electrocatalytic performance for ethylene glycol oxidation reaction (EGOR) and glycerol oxidation reaction (GOR) with the mass activity of 7031 mA mg−1/5117 mA mg−1, which is 4.4/3.9 times higher than that of commercial Pd/C catalysts. Furthermore, the remained mass activity of PdCu NSs is 3991/3851 mA mg−1 after the durability measurement for EGOR/GOR, which confirm PdCu NSs possesses superior stability. We believe that our synthetic strategy could provide robust reference for the development of high-performance eletrocatalysts.

Local-strain-induced CO2 adsorption geometries and electrochemical reduction pathway shift.

Unravelling the influence of strain and geometric effects on the electrochemical reduction of carbon dioxide (CO2RR) on Cu-based (or Pd-based) alloys remains challenging due to complex local microenvironment variables. Herein, we employ two PdCu alloys (nanoparticles and nanodendrites) to demonstrate how CO2RR selectivity can shift from CO to HCOO-. Despite sharing consistent phases, exposed crystal facets, and overall oxidative states, these alloys exhibit different local strain profiles due to their distinct geometries. By integrating experimental data, in-situ spectroscopy, and density functional theory calculations, we revealed that CO2 prefers adsorption on tensile-strained areas with carbon-side geometry, following a *COOH-to-CO pathway. Conversely, on some compressive-strained regions induced by the dendrite-like morphology, CO2 adopts an oxygen-side geometry, favoring an *OCHO-to-HCOO pathway due to the downshift of the d-band center. Notably, our findings elucidate a dominant *OCHO-to-HCOO- pathway in catalysts when featuring both adsorption geometries. This research provides a comprehensive model for local environment of bimetallic alloys, and establishes a clear relationship between the CO2RR pathway shift and variation in local strain environments of PdCu alloys.

D-Band Engineering in Pd-Based Nanowire Networks for Further Enhancement in Ethanol Electrooxidation Reaction.

The development of highly efficient electrocatalysts for the ethanol oxidation reaction (EOR) is essential for the commercialization of direct ethanol fuel cells, yet challenges remain. In this study, a one-pot solution-phase method to synthesize Pd nanowire networks (NNWs) with very high surface-to-volume ratio having numerous twin and grain boundaries is developed. Using the same method, the Pd lattice is further engineered by introducing Ag and Cu atoms to produce AgPd, and CuPd alloy structure which significantly shifts the Pd d-band center upward and downward, respectively due to strain and ligand effects. Theoretical analysis employing density functional theory (DFT) demonstrates that such modification of the d-band center significantly influences the adsorption energies of reactants on the catalytic surface. Owing to their notably high surface-to-volume ratio and the presence of multiple twin and grain boundaries, Pd NNWs demonstrate significantly enhanced electrocatalytic activity toward EOR, ≈7.2 times greater than that of commercial Pd/C. Remarkably, compared to Pd NNWs, AgPd, and CuPd NNWs display enlarged and reduced electrocatalytic activity toward EOR, respectively. Specifically, Ag4Pd7 NNWs achieve a remarkable mass activity of 9.00Amgpd -1 for EOR, which is 13.6 times higher than commercial Pd/C.

Stabilization of Pd0 by Cu Alloying: Theory‐Guided Design of Pd3Cu Electrocatalyst for Anodic Methanol Carbonylation

AbstractElectrocatalytic carbonylation of CO and CH3OH to dimethyl carbonate (DMC) on metallic palladium (Pd) electrode offers a promising strategy for C1 valorization at the anode. However, its broader application is limited by the high working potential and the low DMC selectivity accompanied with severe methanol self‐oxidation. Herein, our theoretical analysis of the intermediate adsorption interactions on both Pd0 and Pd4+ surfaces revealed that inevitable reconstruction of Pd surface under strongly oxidative potential diminishes its CO adsorption capacity, thus damaging the DMC formation. Further theoretical modeling indicates that doping Pd with Cu not only stabilizes low‐valence Pd in oxidative environments but also lowers the overall energy barrier for DMC formation. Guided by this insight, we developed a facile two‐step thermal shock method to prepare PdCu alloy electrocatalysts for DMC. Remarkably, the predicted Pd3Cu demonstrated the highest DMC selectivity among existing Pd‐based electrocatalysts, reaching a peaked DMC selectivity of 93 % at 1.0 V versus Ag/AgCl electrode. (Quasi) in situ spectra investigations further confirmed the predicted dual role of Cu dopant in promoting Pd‐catalyzed DMC formation.

Stabilization of Pd0 by Cu Alloying: Theory-Guided Design of Pd3Cu Electrocatalyst for Anodic Methanol Carbonylation.

Electrocatalytic carbonylation of CO and CH3OH to dimethyl carbonate (DMC) on metallic palladium (Pd) electrode offers a promising strategy for C1 valorization at the anode. However, its broader application is limited by the high working potential and the low DMC selectivity accompanied with severe methanol self-oxidation. Herein, our theoretical analysis of the intermediate adsorption interactions on both Pd0 and Pd4+ surfaces revealed that inevitable reconstruction of Pd surface under strongly oxidative potential diminishes its CO adsorption capacity, thus damaging the DMC formation. Further theoretical modeling indicates that doping Pd with Cu not only stabilizes low-valence Pd in oxidative environments but also lowers the overall energy barrier for DMC formation. Guided by this insight, we developed a facile two-step thermal shock method to prepare PdCu alloy electrocatalysts for DMC. Remarkably, the predicted Pd3Cu demonstrated the highest DMC selectivity among existing Pd-based electrocatalysts, reaching a peaked DMC selectivity of 93 % at 1.0 V versus Ag/AgCl electrode. (Quasi) in situ spectra investigations further confirmed the predicted dual role of Cu dopant in promoting Pd-catalyzed DMC formation.

Synthesis of Helional by Hydrodechlorination Reaction in the Presence of Mono- and Bimetallic Catalysts Supported on Alumina

Hydrodechlorination reaction of 3-(benzo-1,3-dioxol-5-yl)-3-chloro-2-methylacrylaldehyde in the presence of different low metal content heterogeneous mono- or bimetallic catalysts was tested for the synthesis of the fragrance Helional® (3-[3,4-methylendioxyphenyl]-2-methyl-propionaldehyde). In particular, mono Pd/Al2O3, Rh/Al2O3 or bimetallic Pd-Cu/Al2O3, Rh-Cu/Al2O3 catalysts were tested in different reaction conditions from which it emerged that mono-Rh/Al2O3 was the best performing catalyst, allowing achievement of 100% substrate conversion and 99% selectivity towards Helional® in 24 h at 80 °C, p(H2) 1.0 MPa in the presence of a base. To establish correlations between atomic structure and catalytic activity, catalysts were characterized by Cu, Rh and Pd K-edge XANES, EXAFS analysis. These characterizations allowed verification that the formation of Pd-Cu alloys and the presence of Cu oxide/hydroxide species on the surface of the Al2O3 support are responsible for the very low catalytic efficiency of bimetallic species tested.

Tunning of catalytic performance in coupling, reduction and oxidation of hydrothermal assisted mixed metal oxides of Pd and Cu loaded over mesoporous nanostructure titania coated N‐doped silica using rice husk

Silica–titania‐based mesoporous nanomaterials due to their widespread availability and inexpensive cost have been employed in an extensive range of applications, including heterogeneous catalysis. This research article discusses the hydrothermal synthesis of highly efficient heterogeneous nanocatalyst, that is, mixed metal oxides of Pd and Cu immobilized over silica–titania mesoporous nanostructure and its application in coupling, reduction and oxidation reactions. It was characterized by Fourier transform infrared spectroscopy (FTIR), powder X‐ray diffraction (P‐XRD), field emission gun–scanning electron microscopy (FEG‐SEM), energy‐dispersive X‐ray analysis (EDX), high‐resolution transmission electron microscopy (HR‐TEM), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), UV–visible spectroscopy (UV–VIS), Brunauer–Emmett–Teller (BET), X‐ray resonance fluorescence (XRF), photoluminescence (PL) and inductively coupled plasma–atomic emission spectroscopy (ICP‐AES) studies to assemble information regarding various structural features. XPS analysis successfully confirmed the presence of mixed oxidation state of Pd and Cu, that is, Pd(0), Pd(II), Cu(0), Cu(I) and Cu(II) over the nanocatalytic support. TEM images showed that the PdCu alloy had spherical shape with average size between 3 and 4 nm. BET analysis indicated that the catalyst has specific surface area of 57.296 m2 g−1 with average pore diameter of 1.84 nm. The results of TGA and DTA analysis demonstrated that the maximum temperature up to which PC‐TNS can catalysed organic reactions was 170°C. The average crystallite size of PC‐TNS was came around 16.08 nm calculated using Scherrer's equation. Moreover, synthesized heterogeneous nanocatalyst was highly recyclable and FEG‐SEM, P‐XRD and XPS findings confirmed the structural disruption after sixth or seventh catalytic run resulted in decrease in yield of products. In general, nanocatalysts can be convincingly more superior to other heterogeneous nanocatalyst due to their unique features such as high specific surface area, high reusability, high reactivity, high product yield and environmentally friendly.

Mechanisms of aqueous bromate reduction activity enhancement with well-defined bimetallic palladium-based catalysts

Catalytic reduction has been shown to remove bromate (BrO3−) in drinking water without waste stream formation, though most reported catalysts rely on palladium (Pd), a financially and environmentally expensive metal. Emerging efforts show Pd can be partially replaced with less expensive metals in nanoparticle (NP) alloys, with enhanced hydrogenation reactivity. However, it is unclear if novel NP alloys will enhance bromate reduction, and if so whether they can be intelligently designed based on underlying mechanisms of enhancement. Herein, we address this knowledge gap reporting that well-defined alloyed PdCu and PdAg nanoparticles deposited on carbon nanotubes achieve a 3.9-times improvement in catalytic activity versus monometallic Pd catalysts, which further translates to catalysts prepared using straight-forward impregnation methods. Density functional theory results indicate that improved hydrogenation rates are related to optimized BrO3− and H binding on PdM surfaces achieved by electronic effects in PdCu alloys and unique surface ensembles in PdAg alloys. Overall, these catalysts delineate a pathway for improved bromate removal activity at environmentally relevant concentrations.

Electrodeposition of copper on glassy carbon and palladium from choline chloride - ethylene glycol deep eutectic solvent

Electrodeposition of copper from deep eutectic solvents (DES) based on a mixture of choline chloride and ethylene glycol containing CuCl2·2H2O at 50 °C and 80 °C was studied. Electrochemical reduction/oxidation of Cu(II)/Cu(0) on glassy carbon (GC) and palladium (Pd) electrodes was investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV) emphasizing that this process takes place through two steps, Cu(II) ↔ Cu(I) and Cu(I) ↔ Cu(0). The CV results showed that in chloride-rich DES electrolytes, the increased presence of chloro ligands raises the overpotential required for Cu electrodeposition. The electrochemical impedance spectroscopy (EIS) results indicate simultaneous electrodeposition of Cu and electrosorption of large cations on electrodeposited Cu on both GC and Pd substrates. Scanning electron microscopy (SEM) results showed that Cu grains of approximately 1 μm were obtained by electrodeposition of Cu on both Pd and GC, whereby better coverage by electrodeposited Cu was obtained on Pd than on GC. Cu electrodeposited on Pd was relatively uniform and smooth, but porous, while Cu electrodeposited on GC was dispersed in small agglomerates. Energy-dispersive X-ray spectroscopy (EDS) of Cu electrodeposited on Pd detected the dominant presence of Cu with the possibility of the formation of CuPd alloy. The presence of CuPd alloy face-centred cubic structures is confirmed by X-ray diffraction (XRD) along with metallic Cu.

Hydrogen Spillover Accelerates Electrocatalytic Semi-hydrogenation of Acetylene in Membrane Electrode Assembly Reactor.

Electrocatalytic acetylene semi-hydrogenation (EASH) offers a promising and environmentally friendly pathway for the production of C2H4, a widely used petrochemical feedstock. While the economic feasibility of this route has been demonstrated in three-electrode systems, its viability in practical device remains unverified. In this study, we designed a highly efficient electrocatalyst based on a PdCu alloy system utilizing the hydrogen spillover mechanism. The catalyst achieved an operational current density of 600 mA cm-2 in a zero-gap membrane electrode assembly (MEA) reactor, with the C2H4 selectivity exceeding 85%. This data confirms the economic feasibility of EASH in real-world applications. Furthermore, through in situ Raman spectroscopy and theoretical calculations, we elucidated the catalytic mechanism involving interfacial hydrogen spillover. Our findings underscore the economic viability and potential of EASH as a greener and scalable approach for C2H4 production, thus advancing the field of electrocatalysis in sustainable chemical synthesis.

A Cu-Pd alloy catalyst with partial phase separation for the electrochemical CO2 reduction reaction

Cu catalysts can convert CO2 through an electrochemical reduction reaction into a variety of useful carbon-based products. However, this capability provides an obstacle to increasing the selectivity for a single product. Herein, we report a simple fabrication method for a Cu-Pd alloy catalyst for use in a membrane electrode assembly (MEA)-based CO2 electrolyzer for the electrochemical CO2 reduction reaction (ECRR) with high selectivity for CO production. When the composition of the Cu-Pd alloy catalyst was fabricated at 6:4, the selectivity for CO increased and the production of multi-carbon compounds and hydrogen is suppressed. Introducing a Cu-Pd alloy catalyst with 6:4 ratio as the cathode of the MEA-based CO2 electrolyzer showed a CO faradaic efficiency of 92.8% at 2.4 Vcell. We assumed that these results contributed from the crystal planes on the surface of the Cu-Pd alloy. The phases of the Cu-Pd alloy catalyst were partially separated through annealing to fabricate a catalyst with high selectivity for CO at low voltage and C2H4 at high voltage. The results of CO-stripping testing confirmed that when Cu partially separates from the lattice of the Cu-Pd alloy, the desorption of *CO is suppressed, suggesting that C–C coupling reaction is favored.