Preparation of CMC-poly(N-isopropylacrylamide) semi-interpenetrating hydrogel with temperature-sensitivity for water retention.

The CMC-PNIPAM hydrogel with semi-interpenetrating structure and temperature-sensitivity was prepared by in-situ polymerization of N-isopropylacrylamide (NIPAM) in sodium carboxymethylcellulose (CMC) solution at room temperature. The mass ratio of CMC to NIPAM was a key factor influencing the network structure and property of CMC-PNIPAM hydrogel. The low critical phase transition temperature (LCST) of CMC-PNIPAM hydrogels increased from 34.4 °C to 35.8 °C with the mass ratio of CMC to NIPAM rising from 0 to 1.2. The maximum compressive stress of CMC-PNIPAM hydrogel reached to 26.7 kPa and the relaxation elasticity was 52 % at strain of 60 %. The viscoelasticity of CMC-PNIPAM hydrogel was consistent with the generalized Maxwell model. The maximum swelling ratio in deionized water was 170.25 g·g-1 (dried hydrogel) with swelling rate of 2.57 g·g-1·min-1 at 25 °C. CMC-PNIPAM hydrogel hardly absorbed water above LCST, but the swollen hydrogel could release water at the rate of 0.36 g·g-1·min-1 once exceeding LCST. The test of water retention showed that soil mixed with 2 wt% dried CMC-PNIPAM hydrogel could retain 13.08 wt% water after 30 days at 25 °C that was 4.4 times than that of controlled soil without CMC-PNIPAM hydrogel. The semi-interpenetrating CMC-PNIPAM hydrogel showed a potential to conserve water responding to temperature.

CuCl2/FeCl3 Bimetallic Photocatalyst for Sustainable Ethylene Production from Ethanol via Recoverable Redox Cycles.

Photocatalytic conversions of ethanol to valuable chemicals are significant organic synthesis reactions. Herein, we developed a CuCl2/FeCl3 bimetallic photocatalyst for sustainable dehydration of ethanol to ethylene by recoverable redox cycles. The selectivity of ethylene was 98.3% for CuCl2/FeCl3, which is much higher than that of CuCl2 (34.5%) and FeCl3 (86.5%). Due to the ligand-to-metal charge transfer (LMCT) process involved in generating the liquid products, the CuCl2/FeCl3 catalyst will be reduced to CuCl/FeCl2. Oxygen (O2) is required for the recovery of CuCl2/FeCl3 to avoid exhaustion. The soluble Fe3+/Fe2+ redox species deliver catalyst regeneration properties more efficiently than single metal couples, making a series of redox reactions (Cu2+/Cu+, Fe3+/Fe2+, and O2/ethanol couples) recyclable with synergistic effects. A flow reactor was designed to facilitate the continuous production of ethylene. The understanding of bimetallic synergism and consecutive reactions promotes the industrial application process of photocatalytic organic reactions.

Efficient Photothermal Catalytic Oxidation Enabled by Three-Dimensional Nanochannel Substrates.

Photothermal catalysis exhibits promising prospects to overcome the shortcomings of high-energy consumption of traditional thermal catalysis and the low efficiency of photocatalysis. However, there is still a challenge to develop catalysts with outstanding light absorption capability and photothermal conversion efficiency for the degradation of atmospheric pollutants. Herein, we introduced the Co3O4 layer and Pt nanoclusters into the three-dimensional (3D) porous membrane through the atomic layer deposition (ALD) technique, leading to a Pt/Co3O4/AAO monolithic catalyst. The 3D ordered nanochannel structure can significantly enhance the solar absorption capacity through the light-trapping effect. Therefore, the embedded Pt/Co3O4 catalyst can be rapidly heated and the O2 adsorbed on the Pt clusters can be activated to generate sufficient O2- species, exhibiting outstanding activity for the diverse VOCs (toluene, acetone, and formaldehyde) degradation. Optical characterization and simulation calculation confirmed that Pt/Co3O4/AAO exhibited state-of-the-art light absorption and a notable localized surface plasmon resonance (LSPR) effect. In situ diffuse reflectance infrared Fourier transform spectrometry (in situ DRIFTS) studies demonstrated that light irradiation can accelerate the conversion of intermediates during toluene and acetone oxidation, thereby inhibiting byproduct accumulation. Our finding extends the application of AAO's optical properties in photothermal catalytic degradation of air pollutants.

Photoresponsive Hydrogen-Bonded Organic Frameworks-Enabled Organic Photoelectrochemical Transistors for Sensitive Bioanalysis.

A facile route for exponential magnification of transconductance (gm) in an organic photoelectrochemical transistor (OPECT) is still lacking. Herein, photoresponsive hydrogen-bonded organic frameworks (PR-HOFs) have been shown to be efficient for gm magnification in a typical poly(ethylene dioxythiophene):poly(styrenesulfonate) OPECT. Specifically, 450 nm light stimulation of 1,3,6,8-tetrakis (p-benzoic acid) pyrene (H4TBAPy)-based HOF could efficiently modulate the device characteristics, leading to the considerable gm magnification over 78 times from 0.114 to 8.96 mS at zero Vg. In linkage with a DNA nanomachine-assisted steric hindrance amplification strategy, the system was then interfaced with the microRNA-triggered structural DNA evolution toward the sensitive detection of a model target microRNA down to 0.1 fM. This study first reveals HOFs-enabled efficient gm magnification in organic electronics and its application for sensitive biomolecular detection.

Hydrogen Spillover Induced PtCo/CoOx Interfaces with Enhanced Catalytic Activity for CO Oxidation at Low Temperatures in Humid Conditions.

The development of catalysts with abundant active interfaces for superior low-temperature catalytic CO oxidation is critical to meet increasingly rigorous emission requirements, yet still challenging. Herein, this work reports a PtCo/CoOx /Al2 O3 catalyst with PtCo clusters and enriched Pt─O─Co interfaces induced by hydrogen spillover from the Pt sites and self-oxidation process in air, exhibiting excellent performance for CO oxidation at low temperatures and humid conditions. The combination of structural characterizations and in situ Fourier transform infrared spectroscopy reveals that the PtCo cluster effectively prevents CO saturation/poisoning on the Pt surface. Additionally, the presence of Pt─O─Co interfaces in the PtCo/CoOx /Al2 O3 catalyst provides a significant number of active sites for oxygen activation and ─OH formation. This facilitates efficient generation of CO2 at ambient temperature by coupling with nearby adsorbed CO molecules, resulting in superior low-temperature activity and long-term stability for CO oxidation under humid conditions. This work provides a facile route toward rationalizing the design of catalysts with more active interfaces for superior low-temperature CO oxidation under humid conditions for practical applications.

Hydride-doped Ag17Cu10 nanoclusters as high-performance electrocatalysts for CO2 reduction.

The atomically precise metal electrocatalysts for driving CO2 reduction reactions are eagerly pursued as they are model systems to identify the active sites, understand the reaction mechanism, and further guide the exploration of efficient and practical metal nanocatalysts. Reported herein is a nanocluster-based electrocatalyst for CO2 reduction, which features a clear geometric and electronic structure, and more importantly excellent performance. The nanocatalysts with the molecular formula of [Ag17Cu10(dppm)4(PhC≡C)20H4]3+ have been obtained in a facile way. The unique metal framework of the cluster, with silver, copper, and hydride included, and dedicated surface structure, with strong (dppm) and labile (alkynyl) ligands coordinated, endow the cluster with excellent performance in electrochemical CO2 reduction reaction to CO. With the atomically precise electrocatalysts in hand, not only high reactivity and selectivity (Faradaic efficiency for CO up to 91.6%) but also long-term stability (24 h), are achieved.

Reversible Stacking of 2D ZnIn2 S4 Atomic Layers for Enhanced Photocatalytic Hydrogen Evolution.

It is technically challenging to reversibly tune the layer number of 2D materials in the solution. Herein, a facile concentration modulation strategy is demonstrated to reversibly tailor the aggregation state of 2D ZnIn2 S4 (ZIS) atomic layers, and they are implemented for effective photocatalytic hydrogen (H2 ) evolution. By adjusting the colloidal concentration of ZIS (ZIS-X, X = 0.09, 0.25, or 3.0 mg mL-1 ), ZIS atomic layers exhibit the significant aggregation of (006) facet stacking in the solution, leading to the bandgap shift from 3.21 to 2.66 eV. The colloidal stacked layers are further assembled into hollow microsphere after freeze-drying the solution into solid powders, which can be redispersed into colloidal solution with reversibility. The photocatalytic hydrogen evolution of ZIS-X colloids is evaluated, and the slightly aggregated ZIS-0.25 displays the enhanced photocatalytic H2 evolution rates (1.11 µmol m-2 h-1 ). The charge-transfer/recombination dynamics are characterized by time-resolved photoluminescence (TRPL) spectroscopy, and ZIS-0.25 displays the longest lifetime (5.55 µs), consistent with the best photocatalytic performance. This work provides a facile, consecutive, and reversible strategy for regulating the photo-electrochemical properties of 2D ZIS, which is beneficial for efficient solar energy conversion.

Nanograin-Boundary-Abundant Cu2O-Cu Nanocubes with High C2+ Selectivity and Good Stability during Electrochemical CO2 Reduction at a Current Density of 500 mA/cm2.

Surface and interface engineering, especially the creation of abundant Cu0/Cu+ interfaces and nanograin boundaries, is known to facilitate C2+ production during electrochemical CO2 reductions over copper-based catalysts. However, precisely controlling the favorable nanograin boundaries with surface structures (e.g., Cu(100) facets and Cu[n(100)×(110)] step sites) and simultaneously stabilizing Cu0/Cu+ interfaces is challenging, since Cu+ species are highly susceptible to be reduced into bulk metallic Cu at high current densities. Thus, an in-depth understanding of the structure evolution of the Cu-based catalysts under realistic CO2RR conditions is imperative, including the formation and stabilization of nanograin boundaries and Cu0/Cu+ interfaces. Herein we demonstrate that the well-controlled thermal reduction of Cu2O nanocubes under a CO atmosphere yields a remarkably stable Cu2O-Cu nanocube hybrid catalyst (Cu2O(CO)) possessing a high density of Cu0/Cu+ interfaces, abundant nanograin boundaries with Cu(100) facets, and Cu[n(100)×(110)] step sites. The Cu2O(CO) electrocatalyst delivered a high C2+ Faradaic efficiency of 77.4% (56.6% for ethylene) during the CO2RR under an industrial current density of 500 mA/cm2. Spectroscopic characterizations and morphological evolution studies, together with in situ time-resolved attenuated total reflection-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) studies, established that the morphology and Cu0/Cu+ interfacial sites in the as-prepared Cu2O(CO) catalyst were preserved under high polarization and high current densities due to the nanograin-boundary-abundant structure. Furthermore, the abundant Cu0/Cu+ interfacial sites on the Cu2O(CO) catalyst acted to increase the *CO adsorption density, thereby increasing the opportunity for C-C coupling reactions, leading to a high C2+ selectivity.

CeO2/Cu2O/Cu Tandem Interfaces for Efficient Water-Gas Shift Reaction Catalysis.

Metal-oxide interfaces on Cu-based catalysts play very important roles in the low-temperature water-gas shift reaction (LT-WGSR). However, developing catalysts with abundant, active, and robust Cu-metal oxide interfaces under LT-WGSR conditions remains challenging. Herein, we report the successful development of an inverse copper-ceria catalyst (Cu@CeO2), which exhibited very high efficiency for the LT-WGSR. At a reaction temperature of 250 °C, the LT-WGSR activity of the Cu@CeO2 catalyst was about three times higher than that of a pristine Cu catalyst without CeO2. Comprehensive quasi-in situ structural characterizations indicated that the Cu@CeO2 catalyst was rich in CeO2/Cu2O/Cu tandem interfaces. Reaction kinetics studies and density functional theory (DFT) calculations revealed that the Cu+/Cu0 interfaces were the active sites for the LT-WGSR, while adjacent CeO2 nanoparticles play a key role in activating H2O and stabilizing the Cu+/Cu0 interfaces. Our study highlights the role of the CeO2/Cu2O/Cu tandem interface in regulating catalyst activity and stability, thus contributing to the development of improved Cu-based catalysts for the LT-WGSR.

Strain-Engineering of Mesoporous Cs3 Bi2 Br9 /BiVO4 S-Scheme Heterojunction for Efficient CO2 Photoreduction.

Slow charge kinetics and unfavorable CO2 adsorption/activation strongly inhibit CO2 photoreduction. In this study, a strain-engineered Cs3 Bi2 Br9 /hierarchically porous BiVO4 (s-CBB/HP-BVO) heterojunction with improved charge separation and tailored CO2 adsorption/activation capability is developed. Density functional theory calculations suggest that the presence of tensile strain in Cs3 Bi2 Br9 can significantly downshift the p-band center of the active Bi atoms, which enhances the adsorption/activation of inert CO2 . Meanwhile, in situ irradiation X-ray photoelectron spectroscopy and electron spin resonance confirm that efficient charge transfer occurs in s-CBB/HP-BVO following an S-scheme with built-in electric field acceleration. Therefore, the well-designed s-CBB/HP-BVO heterojunction exhibits a boosted photocatalytic activity, with a total electron consumption rate of 70.63 µmol g-1 h-1 , and 79.66% selectivity of CO production. Additionally, in situ diffuse reflectance infrared Fourier transform spectroscopy reveals that CO2 photoreduction undergoes a formaldehyde-mediated reaction process. This work provides insight into strain engineering to improve the photocatalytic performance of halide perovskite.

Atomic-Interface Effect of Single-Atom Ru/CoOx for Selective Electrooxidation of 5-Hydroxymethylfurfural.

The development of single-atom catalysts with effective interfaces for biomass conversion is a promising but challenging research area. In this study, a Ru1/CoOx catalyst was successfully fabricated with the impregnation method, which featured Ru single atoms on a cobalt oxide substrate. The Ru1/CoOx catalyst showed superior performance in the selective electrooxidation of 5-hydroxymethylfurfural (HMF) to produce 2,5-furandicarboxylic acid (FDCA), a high value-added product. The introduction of Ru single atoms with an ultralow loading of ∼0.5 wt % was revealed to accelerate the electroredox of Co2+/Co3+/Co4+ and improve the intrinsic activity of the CoOx substrate with an FDCA selectivity of 76.5%, which is better than that of the pristine CoOx electrocatalysts (62.7%). The interfacial synergistic effect of the Ru1/CoOx interface clarified that Ru single atoms can enhance the adsorption of HMF at the Ru1/CoOx interface, which promoted the rate-determining step of the selective C-H bond activation for FDCA production. This finding provides valuable insights into the rational design of single-atom catalysts with functional interfaces for biomass upgrading.

Polymer Dot-Gated Accumulation-Type Organic Photoelectrochemical Transistor for Urea Biosensing.

Organic photoelectrochemical transistor (OPECT) biosensing represents a new platform interfacing optoelectronics and biological systems with essential amplification, which, nevertheless, are concentrated on depletion-type operation to date. Here, a polymer dot (Pdot)-gated accumulation-type OPECT biosensor is devised and applied for sensitive urea detection. In such a device, the as-designed Pdot/poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) is validated as a superior gating module against the diethylenetriamine (DETA) de-doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) channel, and the urea-dependent status of Pdots has been shown to be sensitively correlated with the device's response. High-performance urea detection is thus realized with a wide linear range of 1 µM-50 mM and a low detection limit of 195 nM. Given the diversity of the Pdot family and its immense interactions with other species, this work represents a generic platform for developing advanced accumulation-type OPECT and beyond.

Quenching-Induced Defect-Rich Platinum/Metal Oxide Catalysts Promote Catalytic Oxidation.

Enhancing oxygen activation through defect engineering is an effective strategy for boosting catalytic oxidation performance. Herein, we demonstrate that quenching is an effective strategy for preparing defect-rich Pt/metal oxide catalysts with superior catalytic oxidation activity. As a proof of concept, quenching of α-Fe2O3 in aqueous Pt(NO3)2 solution yielded a catalyst containing Pt single atoms and clusters over defect-rich α-Fe2O3 (Pt/Fe2O3-Q), which possessed state-of-the-art activity for toluene oxidation. Structural and spectroscopic analyses established that the quenching process created abundant lattice defects and lattice dislocations in the α-Fe2O3 support, and stronger electronic interactions between Pt species and Fe2O3 promote the generation of higher oxidation Pt species to modulate the adsorption/desorption behavior of reactants. In situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) characterization studies and density functional theory (DFT) calculations determined that molecular oxygen and Fe2O3 lattice oxygen were both activated on the Pt/Fe2O3-Q catalyst. Pt/CoMn2O4, Pt/MnO2, and Pt/LaFeO3 catalysts synthesized by the quenching method also offered superior catalytic activity for toluene oxidation. Results encourage the wider use of quenching for the preparation of highly active oxidation catalysts.

CuC(O) Interfaces Deliver Remarkable Selectivity and Stability for CO2 Reduction to C2+ Products at Industrial Current Density of 500 mA cm-2.

The electrocatalytic CO2 reduction reaction (CO2 RR) is an attractive technology for CO2 valorization and high-density electrical energy storage. Achieving a high selectivity to C2+ products, especially ethylene, during CO2 RR at high current densities (>500 mA cm-2 ) is a prized goal of current research, though remains technically very challenging. Herein, it is demonstrated that the surface and interfacial structures of Cu catalysts, and the solid-gas-liquid interfaces on gas-diffusion electrode (GDE) in CO2 reduction flow cells can be modulated to allow efficient CO2 RR to C2+ products. This approach uses the in situ electrochemical reduction of a CuO nanosheet/graphene oxide dots (CuOC(O)) hybrid. Owing to abundant CuOC interfaces in the CuOC(O) hybrid, the CuO nanosheets are topologically and selectively transformed into metallic Cu nanosheets exposing Cu(100) facets, Cu(110) facets, Cu[n(100) × (110)] step sites, and Cu+ /Cu0 interfaces during the electroreduction step, the faradaic efficiencie (FE) to C2+ hydrocarbons was reached as high as 77.4% (FEethylene  ≈ 60%) at 500 mA cm-2 . In situ infrared spectroscopy and DFT simulations demonstrate that abundant Cu+ species and Cu0 /Cu+ interfaces in the reduced CuOC(O) catalyst improve the adsorption and surface coverage of *CO on the Cu catalyst, thus facilitating CC coupling reactions.

Photodehydration of Ethanol Mediated by CuCl2-Ethanol Complex.

Biomass ethanol is regarded as a renewable resource but it is not economically viable to transform it to high-value industrial chemicals at present. Herein, a simple, green, and low-cost CuCl2-ethanol complex is reported for ethanol dehydration to produce ethylene and acetal simultaneously with high selectivity under sunlight irradiation. Under N2 atmosphere, the generation rates of ethylene and acetal were 165 and 3672 µmol g-1 h-1, accounting for 100% in gas products and 97% in liquid products, respectively. An outstanding apparent quantum yield of 13.2% (365 nm) and the maximum conversion rate of 32% were achieved. The dehydration reactions start from the photoexcited CuCl2-ethanol complex, and then go through the energy transfer (EnT) and ligand to metal charge transfer (LMCT) mechanisms to produce ethylene and acetal, respectively. The formation energies of the CuCl2-ethanol complex and the key intermediate radicals (e.g., ·OH, CH3CH2·, and CH3CH2O·) were validated to clarify the mechanisms. Different from previous CuCl2-based oxidation and addition reactions, this work is anticipated to supply new insights into the dehydration reaction of ethanol to produce useful chemical feedstocks.

Toward More Efficient Carbon-Based Electrocatalysts for Hydrogen Peroxide Synthesis: Roles of Cobalt and Carbon Defects in Two-Electron ORR Catalysis.

Electrochemical production of H2O2 is a cost-effective and environmentally friendly alternative to the anthraquinone-based processes. Metal-doped carbon-based catalysts are commonly used for 2-electron oxygen reduction reaction (2e-ORR) due to their high selectivity. However, the exact roles of metals and carbon defects on ORR catalysts for H2O2 production remain unclear. Herein, by varying the Co loading in the pyrolysis precursor, a Co-N/O-C catalyst with Faradaic efficiency greater than 90% in alkaline electrolyte was obtained. Detailed studies revealed that the active sites in the Co-N/O-C catalysts for 2e-ORR were carbon atoms in C-O-C groups at defect sites. The direct contribution of cobalt single atom sites and metallic Co for the 2e-ORR performance was negligible. However, Co plays an important role in the pyrolytic synthesis of a catalyst by catalyzing carbon graphitization, tuning the formation of defects and oxygen functional groups, and controlling O and N concentrations, thereby indirectly enhancing 2e-ORR performance.

Alkaline Phosphatase-Mediated Bioetching of CoOOH/BiVO4 for Signal-On Organic Photoelectrochemical Transistor Bioanalysis.

Organic photoelectrochemical transistor (OPECT) bioanalytics has recently appeared as a promising route for biological measurements, which has major implications in both next-generation photoelectrochemical (PEC) bioanalysis and futuristic biorelated implementations. Via biological dissociation of materials, bioetching is a useful technique for bio-manufacturing and bioanalysis. The intersection of these two domains is expected to be a possible way to achieve innovative OPECT bioanalytics. Herein, we validate such a possibility, which is exemplified by alkaline phosphatase (ALP)-mediated bioetching of a CoOOH/BiVO4 gate for a signal-on OPECT immunoassay of human immunoglobulin G (HIgG) as the model target. Specifically, target-dependent bioetching of the upper CoOOH layer could result into an enhanced electrolyte contact and light accessibility to BiVO4, leading to the modulated response of the polymeric poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) channel that could be monitored by the channel current. The introduced biosensor achieves sensitive detection of HIgG with high selectivity and sensitivity. This work features bioetching-enabled high-efficacy OPECT bioanalysis and is anticipated to serve as a generic protocol, considering the diverse bioetching routes.

Enhanced Red Emission from Amorphous Silicon Carbide Films via Nitrogen Doping.

The enhanced red photoluminescence (PL) from Si-rich amorphous silicon carbide (a-SiCx) films was analyzed in this study using nitrogen doping. The increase in nitrogen doping concentration in films results in the significant enhancement of PL intensity by more than three times. The structure and bonding configuration of films were investigated using Raman and Fourier transform infrared absorption spectroscopies, respectively. The PL and analysis results of bonding configurations of films suggested that the enhancement of red PL is mainly caused by the reduction in nonradiative recombination centers as a result of the weak Si-Si bonds substituted by Si-N bonds.

Molecular Assembled Electrocatalyst for Highly Selective CO2 Fixation to C2+ Products.

In certain metalloenzymes, multimetal centers with appropriate primary/secondary coordination environments allow carbon-carbon coupling reactions to occur efficiently and with high selectivity. This same function is seldom realized in molecular electrocatalysts. Herein we synthesized rod-shaped nanocatalysts with multiple copper centers through the molecular assembly of a triphenylphosphine copper complex (CuPPh). The assembled molecular CuPPh catalyst demonstrated excellent electrochemical CO2 fixation performance in aqueous solution, yielding high-value C2+ hydrocarbons (ethene) and oxygenates (ethanol) as the main products. Using density functional theory (DFT) calculations, in situ X-ray absorption spectroscopy (XAS) and quasi-in situ X-ray photoelectron spectroscopy (XPS), and reaction intermediate capture, we established that the excellent catalytic performance originated from the large number of double copper centers in the rod-shaped assemblies. Cu-Cu distances in the absence of CO2 were as long as 7.9 Å, decreasing substantially after binding CO2 molecules indicating dynamic and cooperative function. The double copper centers were shown to promote carbon-carbon coupling via a CO2 transfer-coupling mechanism involving an oxalate (OOC-COO) intermediate, allowing the efficient production of C2+ products. The assembled CuPPh nanorods showed high activity, excellent stability, and a high Faradaic efficiency (FE) to C2+ products (65.4%), with performance comparable to state-of-the-art copper oxide-based catalysts. To our knowledge, our findings demonstrate that harnessing metalloenzyme-like properties in molecularly assembled catalysts can greatly improve the selectivity of CO2RR, promoting the rational design of improved CO2 reduction catalysts.

In Situ Engineering of the Cu+/Cu0 Interface to Boost C2+ Selectivity in CO2 Electroreduction.

The Cu+/Cu0 interface in the Cu-based electrocatalyst is essential to promote the electrochemical reduction of carbon dioxide (ERCO2) to produce multi-carbon hydrocarbons and alcohols with high selectivity. However, due to the high activity of the Cu+/Cu0 interface, it is easy to be oxidized in the air. How to control and prepare a Cu-based electrocatalyst with an abundant and stable Cu+/Cu0 interface in situ is a huge challenge. Here, combined with density functional theory (DFT) calculations and experimental studies, we found that the trace halide ions adsorbed on Cu2O can slow the reduction kinetics of Cu+ → Cu0, which allowed us to in-situ well control the synthesis of the CuO-derived electrocatalyst with rich Cu+/Cu0 interfaces. Our Cu catalyst with a rich Cu+/Cu0 interface exhibits excellent ERCO2 performance. Under the operation potential of -0.98 V versus RHE, the Faraday efficiency of C2H4 and C2+ products are 55.8 and 75.7%, respectively, which is about 16% higher than that of CuO-derived electrocatalysts that do not use halide ions. The high FEC2+ comes from the improvement of the coupling efficiency of reaction intermediates such as CO-CO, which is proved by DFT calculations, and the suppression of hydrogen evolution reaction. Therefore, we provide an in-situ engineering strategy, which is simple and effective for the design and preparation of high-performance ERCO2 catalysts.