Copper Doped Zinc Oxide Research Articles

Expression of Concern: Electrical Study of Trapped Charges in Copper-Doped Zinc Oxide Films by Scanning Probe Microscopy for Nonvolatile Memory Applications.

Expression of Concern: Electrical Study of Trapped Charges in Copper-Doped Zinc Oxide Films by Scanning Probe Microscopy for Nonvolatile Memory Applications.

Adsorption, Kinetics and Thermodynamics of Reactive Blue 21 Textile Dyestuff Using Copper Doped Zinc Oxide Nanocomposite Decorated on Kaolin Surface

Bu çalışmanın amacı; tekstil endüstrisinde yaygın olarak kullanılan bir boyarmadde olan Reaktif Mavi 21 (RM21)’in atık sulardan adsorpsiyon yöntemiyle uzaklaştırılmasında kaolin yüzeyine dekore edilmiş bakır katkılı çinko oksit nanokompozitinin adsorban olarak kullanılabilirliğinin araştırılmasıdır. Adsorpsiyon üzerine, başlangıç RM21 konsantrasyonu, adsorban miktarı, sıcaklık ve denge süresi gibi çeşitli deneysel parametrelerin etkileri incelenmiştir. Adsorpsiyon hızının ikinci mertebeden hız ifadesine uyduğu ve kaolin yüzeyine dekore edilmiş bakır katkılı çinko oksit nanokompozitinin RM21 üzerine adsorpsiyonunun Redlich-Peterson izoterm modeliyle uyum sağladığı görülmüştür. Bu çalışmanın sonuçları, RM21’nin sulu çözeltilerden uzaklaştırılmasında kaolin yüzeyine dekore edilmiş bakır katkılı çinko oksit nanokompozitinin etkili bir adsorban olarak kullanılabileceğini göstermiştir.

All-in-one supercapacitors with high performance enabled by Mn/Cu doped ZnO and MXene

Here, we report the development of high-performance supercapacitor devices using manganese-doped zinc oxide nanowires (Mn-doped ZnO NWs) and copper-doped zinc oxide nanoparticles (Cu-doped ZnO NPs) as a positive electrode with MXene as a negative electrode. Both transition metal (TM)-based electrodes were used separately with MXene, and the performance was tested. When used in combination with MXene as a second electrode, TM-ZnO samples displayed a major increase in the supercapacitors’ performance. The highest-performance supercapacitor recorded values of 151 F/g specific capacitance along with 84 Wh/kg energy density and a power density of 75 kW/kg. Electron paramagnetic resonance and photoluminescence spectroscopy of Mn/Cu-doped ZnO reveals intrinsic and extrinsic defect signals, which were discussed and attributed to the enhancement of the capacitive performance. The presence of the aforementioned defects optimizes the intrinsic properties and boosts the reaction kinetics, thus providing increased electrochemical activity and superior supercapacitor device performance.

Copper-Doped Zinc Oxide Nanoparticles: Synthesis, Characterization, and Application for Adsorptive Removal of Toxic Azo Dye

The goal of this research was to employ copper-doped zinc oxide nanoparticles (Cu/ZnONPs) as an adsorbent to remove the potentially toxic azo dye Congo red (CR). The Cu/ZnONPs were made using a chemical coprecipitation method, and their characteristics were examined using XRD, SEM, EDS, and FTIR methods. The response surface methodology (RSM) central composite design (CCD) is used to optimize the operational parameters’ agitation time, adsorbent dosage, solution pH, and initial concentration of CR solution during the adsorption process. The agitation period of 29.48 min, the Cu/ZnONP dosage of 0.301 g/L, the solution pH of 6.96, and the CR initial concentration of 90 mg/L resulted in a maximum CR adsorption of 94.14% and a desirability of 0.976. The kinetic findings fit the pseudo-second-order kinetic equation, and the equilibrium data agreed with the Langmuir isotherm (maximum uptake capacity qmax = 250 mg/g). During the thermodynamic experiments, endothermic, spontaneous, and physical adsorptions were observed.

Dye-sensitized solar cells fabricated using ZnO:Cu thin films and dye extracted from Hypericum perforatum L. flowers

Dye-sensitized solar cells (DSSC) were designed utilizing pure and copper-doped zinc oxide (ZnO:Cu) nanoparticles and the dye extracted from dried Hypericum perforatum L. (H. perforatum) flowers. The ZnO:Cu thin films were grown using the successive ionic layer adsorption and reaction (SILAR) method on tin-doped indium oxide-coated (ITO) glass substrates at 85 °C. Regarding the molar ratio of Cu ions to Zn ions, Cu had a doping concentration of 0.5%, 1%, and 2%. The crystalline nature, morphological, compositional, and optical properties of the synthesized ZnO:Cu thin films were studied using an X-ray diffractometer (XRD), a scanning electron microscope (SEM), energy dispersive x-ray spectrometry (EDS), UV-vis spectroscopy, and Fourier transformation infrared (FTIR) spectroscopy. The SEM results indicated the formation of a porous structure on the surface of ZnO:Cu thin films, which provided more active sites for dye molecules and electrolyte ions. A DSSC, produced by using a pure ZnO thin film, showed a current density (Jsc) of 7.66 mA/cm2 with an open-circuit voltage (Voc) of 0.98 V and an overall efficiency (η) of 2.47%

Micelle encapsulation zinc-doped copper oxide nanocomposites reverse Olaparib resistance in ovarian cancer by disrupting homologous recombination repair.

Micelle Encapsulation Zinc-doped copper oxide nanocomposites (MEnZn-CuO NPs) is a novel doped metal nanomaterial prepared by our group based on Zinc doped copper oxide nanocomposites (Zn-CuO NPs) using non-micellar beam. Compared with Zn-CuO NPs, MEnZn-CuO NPs have uniform nanoproperties and high stability. In this study, we explored the anticancer effects of MEnZn-CuO NPs on human ovarian cancer cells. In addition to affecting cell proliferation, migration, apoptosis and autophagy, MEnZn-CuO NPs have a greater potential for clinical application by inducing HR repair defects in ovarian cancer cells in combination with poly (ADP-ribose) polymerase inhibitors for lethal effects.

Structural, Optical, and Renewable Energy-Assisted Photocatalytic Dye Degradation Studies of ZnO, CuZnO, and CoZnO Nanostructures for Wastewater Treatment

Renewable energy can be harnessed from wastewater, whether from municipalities or industries, but this potential is often ignored. The world generates over 900 km3 of wastewater annually, which is typically treated through energy-consuming processes, despite its potential for energy production. Environmental pollution is a most important and serious issue for all and their adulterations to the aquatic system are very toxic in very low concentrations. Photocatalysis is a prominent approach to eliminating risky elements from the environment. The present study developed Zinc oxide (ZnO), Copper-doped Zinc oxide (CuZnO), and Cobalt-doped Zinc oxide (CoZnO) nanostructures (NSs) by facile hydrothermal route. The crystalline and structural stability of the synthesized nanostructures were evident from XRD and FESEM analysis. Metal, and oxygen bond and their interaction on the surfaces and their valency were explored from XPS spectra. Optical orientations and electron movements were revealed from UV-Visible analysis. After 100 min exposure time with 1 g of catalyst concentration 60%, 70%, and 89% of dye degraded, for dye concentration (5 mg/L to 50 mg/L), the huge variation observed (70% to 22%), (80% to 16%), (94% to 10%). The highest photodegradation rate (55%, 75%, 90%) was observed on pH~12 using ZnO, CoZnO, and CuZnO respectively. Photodegradation of methylene blue confirmed the largest surface area, rate of recombination, photo-excited charge carriers, photo-sensitivity range, and radical generations of ZnO, CuZnO, and CoZnO. The present study, therefore, suggested that CuZnO would be preferred to produce nanomaterials for industrial wastewater treatment like methylene.

Cu/CuO-Doped ZnO Nanocomposites via Solution Combustion Synthesis for Catalytic 4-Nitrophenol Reduction.

The synthesis of optoelectrically enhanced nanomaterials should be continuously improved by employing time- and energy-saving techniques. The porous zinc oxide (ZnO) and copper-doped ZnO nanocomposites (NCs) were synthesized by the time- and energy-efficient solution combustion synthesis (SCS) approach. In this SCS approach, once the precursor-surfactant complex ignition point is reached, the reaction starts and ends within a short time without the need for any external energy. The TGA-DTA analysis confirmed that 500 °C was the point at which stable metal oxide was obtained. The doping and heterojunction strategy improved the optoelectric properties of the NCs more than the individual constituents, which then enhanced the materials' charge transfer and optical absorption capabilities. The porosity, nanoscale crystallite size (15-50 nm), and formation of Cu/CuO-ZnO NCs materials were confirmed from the XRD, SEM, and TEM/HRTEM analyses. The obtained d-spacing values of 0.275 and 0.234 nm confirm the formation of ZnO and CuO crystals, respectively. The decrease in photoluminescence intensity for the doped NCs corroborates a reduction in electron-hole recombination. On the Mott-Schottky analysis, the positive slope for ZnO confirms the n-type character, while the negative and positive slopes of the NCs confirm the p- and n-type characters, respectively. A diffusion-controlled type of charge transfer process on the electrode surface was confirmed from the cyclic voltammetric analysis. Thus, the overall analysis shows the applicability of the less expensive and more efficient SCS for several applications, such as catalysis and sensors. To confirm this, an organic catalytic reduction reaction of 4-nitrophenol to 4-aminophenol was tested. Within three and a half minutes, the catalytic reduction result showed the great potential of NCs over ZnO NPs. Thus, the energy- and time-saving SCS approach has a great future outlook as an industrial pollutant catalytic reduction application.

Folic-acid adorned alginate-polydopamine modified paclitaxel/Zn-CuO nanocomplex for pH triggered drug release and synergistic antitumor efficacy

Targeted chemotherapy is a prominent cancer treatment research trend that intends to boost the efficacy of drug delivery to cancer cells. The present work aimed to design, a folate-decorated biologically inspired alginate-polydopamine capped zinc doped copper oxide nanoparticles (Zn-CuO) loaded with paclitaxel (Zn-CuO@PTX/AlgPDA-FA) as a simple, efficient, and versatile nanoplatform. Interestingly, Zn species doped in CuO frameworks significantly improved paclitaxel (PTX) molecule loading efficiency without requiring any additional functionalization and fostered the increased antitumor efficacy by precisely delivering them in tumor's acidic microenvironment by obliterating the formed coordination connections between the host as well as guest species. According to DLS, average size of nanocomplex was 196 ± 5.01 nm with ȥ-potential −31.4 ± 1.54 mV. PTX encapsulation and loading efficiencies were 75.2 ± 1.54 % and 18.54 ± 2.31 %, respectively. Furthermore, nanocomplex demonstrates high stability and biocompatibility in vitro. Under an acidic environment (pH 5.0), there was greater PTX release compared to normal physiological conditions. Moreover, Zn-CuO@PTX/AlgPDA-FA NPs showed remarkable internalization efficiency in MCF-7 cells and demonstrated strong cytotoxicity with IC50 (150 ± 2.58 μg/mL) along with improved ROS generation and changed mitochondrial membrane potential level. Therefore, our approach could suggest excellent potential for tumor targeting in cancer therapy with reduced off-target toxicity, and desirable therapeutic effects.

Inquest on photocatalytic and antibacterial traits of low composition Cu doped ZnO nanoparticles

Copper-doped Zinc Oxide nanoparticles (Zn1-xCuxO; x = 0, 0.025, and 0.05) were synthesized by viable hydrothermal method. Structural, morphological, and optical studies were done to characterize the material’s properties. The samples were tested as adsorbents to study their dye degradation potential using Methylene Blue (MB) as a model dye. The antibacterial potential of ZnO nanorods upon Cu doping was performed by disc diffusion method against both gram-negative and gram-positive bacteria. The results thus reveal the practical applicability of prepared samples in photodegradation and antibacterial applications.

Application of Non-Enzymatic Lactate Sensor Modified by Graphitic Carbon Nitride/Iron–Platinum Nanoparticles and Combined With the Low Power Consumption Instrumentation Amplifier and Calibration Readout Circuit

In a previous study, this laboratory produced and tested a lactic acid biosensor using a copper-doped zinc oxide (CZO) sensing film modified with graphite carbon nitride (g-C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) and iron platinum nanoparticles (FePt NPs). The previous sensor exhibited two non-ideal effects during persistent use and when alternating between high and low lactose concentrations. Using a low unity-gain frequency and low power consumption instrumentation amplifier (UGFPCIA) in conjunction with a calibration readout circuit, it was possible to reduce the previously observed drift and hysteresis effects. The UGFPCIA and calibration readout circuit were connected to a voltage-time (V-T) measurement system so the effects could be accurately quantified. The influence of the UGFPCIA on the measurement characteristics of the lactate biosensor were recorded and compared to a similar device using a commercial LT1167. Results showed that the UGFPCIA produced a more stable measurement, where linearity increased from 0.985 to 0.998. When measuring interference effects, the fluctuation in response voltage became smaller, and the time drift effect was successfully reduced by 89.7%. The hysteresis effect reduced the forward period by 0.13 mV, and the reverse period by 4.37 mV.

Preparation of dynamic polyurethane networks with UV-triggered photothermal self-healing properties based on hydrogen and ion bonds for antibacterial applications

• The building of Zn-dimethylglyoxime-polyurethane coordination complex provides a covalently cross-linked elastomer with triple dynamic bonds. • The self-healing behavior and mechanism of 3D micro-crack is investigated by molecular dynamics simulations. • The doping of copper on double-nut shaped zinc oxide generates more defects, preventing the recombination of photo-induced electron-hole pairs and generating more heat through lattice vibration. • The enhanced self-healing effect of UV-light-responsive polyurethane was due to the hybrid of Cu-doped ZnO, which provides coordination bonds and the photothermal effect. Photo-induced self-healing composites have attracted more and more attention as a kind of materials that can be controlled remotely and accurately in real time. Here, we report a strategy of a photo-responsive system based on hydrogen and ion bonds capable of performing self-healing process by ultraviolet wavelengths, which is covalently cross-linked zinc-dimethylglyoxime-polyurethane coordination network with triple dynamic bonds. The recombination of hydrogen bond and metal coordination bond produces effective healing performance. The self-healing behavior and temperature dependence of 3D micro-crack is investigated by molecular dynamics simulations to reveal the mechanism of self-healing at molecular level. Moreover, the hybrid of copper-doped zinc oxide not only provides metal coordination bonds to enhance the self-healing rate, but also enhances the photothermal effect and anti-bacterial properties of polyurethane. Importantly, doping of copper generates more defects and forms a space charge layer on the surface of zinc oxide. The defects could trap surface electrons and holes, preventing the recombination of photo-induced electron-hole pairs, generating more heat through lattice vibration. Therefore, under ultraviolet light irradiation, the polyurethane can reach 62.7°C for 60 s, and the scratches of the polyurethane can be healed within 30 min and fully healed within 1 h.

Production of negative temperature coefficient thermistors from copper-doped zinc oxide via combustion reaction

Production of negative temperature coefficient thermistors from copper-doped zinc oxide via combustion reaction

Synthesis, structure, and improved frequency-dependent transport properties of copper doped zinc oxide nanoparticles at high temperatures

The nanostructures of ZnO are studied in this research utilizing a simple, eco-friendly, and cost-effective co-precipitation have a formula Zn 1 − x Cu ( x ) O with (x = 0.0, 0.03, 0.06, and 0.10). The effects of copper (Cu) doping on structure, morphology, impedance, dielectric, and electrical conductivity were investigated using an XRD, SEM, and LCR meter, respectively. All prepared samples have a hexagonal wurtzite structure, and the average crystalline size varies between 46 and 56 nm, according to the XRD spectra. Impedance measured data analyzes that a capacitance phase element perfectly modulates the fabricated samples with the equivalent circuits. Depending on the temperature, the examination of complex impedance and complex electrical modulus revealed a non-Debye types relaxation process. The Arrhenius plots for the conduction mechanism were used to investigate single activation energy. A correlated barrier hopping (CBH) model dominated the conduction process in un-doped and Cu-doped ZnO nanoparticles. The dielectric measurements in low-frequency at high temperatures regions exhibited high dielectric constant values for the prepared samples. Compared to undoped ZnO, the dielectric constant values increase with Cu concentration, also improving the ac conductivity of all Cu-doped ZnO nanoparticles, making them a suitable choice for energy storage applications. The electrical modulus displays a dual nature of relaxation times for all synthesized samples with lower values. • Pure ZnO and Cu-doped ZnO nanostructures have been fabricated using a Co-precipitation method. • The average crystalline size of ZnO and Cu-doped ZnO nanostructures lies at 46 nm to 56 nm. • The samples of pure and Cu-doped ZnO nanostructures showed negative temperature coefficient resistance (NTCR). • Dielectric and ac conductivity properties improved with the addition of Cu concentrations. • The Cu-doped ZnO nanostructures shall be beneficial for optoelectronics applications.

Iron and Copper Doped Zinc Oxide Nanopowders as a Sensitizer of Industrial Energetic Materials to Visible Laser Radiation.

The development of methods ensuring reliable control over explosive chemical reactions is a critical task for the safe and efficient application of energetic materials. Triggering the explosion by laser radiation is one of the promising methods. In this work, we demonstrate a technique of applying the common industrial high explosive pentaerythritol tetranitrate (PETN) as a photosensitive energetic material by adding zinc oxide nanopowders doped with copper and iron. Nanopowders of ZnO:Fe and ZnO:Cu able to absorb visible light were synthesized. The addition of one mass percent nanopowders in PETN decreased the threshold energy density of its initiation through Nd:YAG laser second harmonic (2.33 eV) by more than five times. The obtained energetic composites can be reliably initiated by a CW blue laser diode with a wavelength of 450 nm and power of 21 W. The low threshold initiation energy and short irradiation exposure of the PETN-ZnO:Cu composite makes it applicable in laser initiation devices. PETN-ZnO:Cu also can be initiated by an infrared laser diode with a wavelength of 808 nm. The proposed photochemical mechanism of the laser-induced triggering of the explosion reaction in the studied energetic composites was formulated. The results demonstrate the high promise of using nanomaterials based on zinc oxide as a sensitizer of industrial energetic materials to visible laser radiation.

Effect of dopant oxidation states on enhanced low ppm CO sensing by copper doped zinc oxide

Chemiresistive gas sensing by functional ceramics, like semiconductor metal oxides have been so far explained in terms of parameters such as particle size, morphology, temperature, oxygen vacancies, surface charge imbalance and so on. However, the effects of oxidation states of dopants in shaping gas sensing behavior in chemiresistors have been largely ignored. In this work, the role of oxidation states of Cu dopants on improved CO sensing behaviour of ZnO has been categorically analyzed. In this process, a multi-fold enhanced and selective sensing response towards low ppm CO in comparison to pure zinc oxide has been achieved by n-type Cu doped Zinc Oxide. Extensive studies on surface electronic and bulk crystal structures have revealed that relative amount of Cu1+ and Cu2+ is the probable primary cause behind enhanced CO sensing response by Cu doped zinc oxide. Our results thus indicate that by modifying the relative amounts of different oxidation states of dopants, semiconductor metal oxide systems may be tuned to show improved sensing response towards CO and other gases.

Influence of heat treatment on zinc oxide nanostructured film grown by immersion method for nanogenerator application

The zinc oxide (ZnO) and copper-doped ZnO (Cu:ZnO) films were synthesized by an immersion method on a sheet of aluminium foil as a substrate. Investigations were conducted into how heat treatment affected the output nanogenerator performance, surface morphological characteristics and structural properties. The field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) was used to characterize the structural properties of the ZnO and Cu:ZnO films-based triboelectric nanogenerators (TENGs), and an oscilloscope was used to indicate the triboelectric response. ZnO and Cu:ZnO films exhibited an increment in average diameter size and showed good crystallinity after heat treatment. The output performance of ZnO and Cu:ZnO films based on TENGs in contact and separation mode by finger tapping was investigated. The output voltage of ZnO and Cu:ZnO films based on TENGs after heat treatment achieved a maximum of 0.63 V and 1.65 V, respectively. This study provides an essential insight into TENGs based on ZnO without a seed layer through a straightforward and inexpensive fabrication technique for nanogenerator applications.[copyright information to be updated in production process]

Coated Cu-doped ZnO and Cu nanoparticles as control agents against plant pathogenic fungi and nematodes

In the current study, coated copper nanoparticles with polyethylene glycol 8000 (Cu@PEG NPs) and copper-doped zinc oxide nanoparticles with diethylene glycol (Cu-doped ZnO@DEG NPs) have been synthesized via solvothermal and microwave-assisted process, physicochemical characterized, and studied as nano-fungicides and nano-nematicides. Spheroidal Cu-doped ZnO@DEG NPs and urchin-like Cu@PEG NPs have been isolated with average crystallite sizes of 12 and 21 nm, respectively. The Cu doping (11.3 wt%) in ZnO lattice (88.7 wt%) was investigated by Rietveld refinement analysis and confirmed by X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). The Cu-doped ZnO@DEG and Cu@PEG NPs revealed a growth inhibition of fungi Botrytis cinerea (B. cinerea) and Sclerotinia sclerotiorum (S. sclerotiorum) and nematode paralysis of Meloidogyne javanica in a dose-dependent manner. Cu-doped ZnO@DEG NPs were more effective against M. javanica (EC50 = 2.60 μg/mL) than the Cu@PEG NPs (EC50 = 25 μg/mL). In contrast, the antifungal activity was approximately similar for both NPs, with EC50 values at 310 and 327 μg/mL against B. cinerea, respectively, and 260 and 278 μg/mL against S. sclerotiorum, respectively. Lettuce (Lactuca sativa) plants were inoculated with S. sclerotiorum or M. javanica and sprayed with either Cu-doped ZnO@DEG NPs or Cu@PEG NPs. The antifungal effect was evaluated based on a disease index (DI), and nematicidal activity was assessed based on the total number of galls and nematode females per root gram. NPs successfully inhibited the growth of both pathogens without causing phytotoxicity on lettuce. The DI were significantly decreased as compared to the positive control (DI = 5.2), estimated equal to 1.7, 2.9 and 2.5 for Cu@PEG NPs, Cu-doped ZnO@DEG NPs and the chemical control (KOCIDE 2000), respectively. The reduction in galling and population of M. javanica ranged from 39.32% to 32.29%, statistically like chemical control. The treatment of lettuce plants with Cu-doped ZnO@DEG NPs increased the leaf net photosynthetic value at 4.60 and 6.66 μmol CO2−2 s−1 in plants inoculated with S. sclerotiorum and M. javanica, respectively, as compared to the control (3.00 μmol CO2−2 s−1). The antioxidant capacity of NPs treated lettuce plants was evaluated as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity in leaf extracts. Plants inoculated with S. sclerotiorum and sprayed with Cu-doped ZnO@DEG and Cu@PEG NPs, exhibited a 34.22% and 32.70% increase in antioxidant capacity, respectively, higher than the control. Similarly, an increase in antioxidant capacity was measured (39.49 and 37.36%) in lettuce inoculated with M. javanica and treated with Cu-doped ZnO@DEG and Cu@PEG NPs, respectively. Moreover, an increase of phenolic compounds in lettuce leaf tissue treated with NPs was measured as compared to the control. Overall, foliar applied Cu and Cu-doped ZnO NPs could be a promising tool to control phytopathogenic fungi and nematodes contributing to sustainability of agri-food sector.

Emulation of bio-synaptic behaviours in copper-doped zinc oxide memristors: A nanoscale scanning probe microscopic study

Memristors emulating biological synapses to perform memory and learning functions are crucial for realizing bio-inspired neuromorphic systems. However, to meet the increasing demand for high-speed operation, low power consumption, and large integration density in neuromorphic architectures, the synaptic functions must be achieved at nanometer scale and with ultra-low write current. This report evidences electronic synapses realized in Cu-doped ZnO (CZO) memristors by nanoscale scanning probe microscopic techniques. In this process, the device can be downsized all the way up to the size of the probe, offering ultra-high density (>109 devices/mm2) of electronic synapses. The essential bio-synaptic functions in the memristor are accomplished with ultra-low write current (∼10 nA) and in a forming-free approach that marks their potential in building power-efficient computing systems. The modulation in device conductivity is elucidated on the basis of charged defect migration, forming conducting bridges across the thickness or locally within the CZO layer. In addition, the influence of Cu-doping in controlling nanoscale neuromorphic and memristive performances of the device is explored. The present study, therefore, demonstrates a novel approach to decipher oxide-based synaptic-memristors and highlights CZO as a promising candidate to fabricate ultra high-density power-efficient neuromorphic devices.

Tuning the local electronic structure of oxygen vacancies over copper-doped zinc oxide for efficient CO2 electroreduction

Oxygen vacancies in metal oxides can serve as electron trap centers to capture CO2 and lower energy barriers for the electrochemical CO2 reduction reaction (CO2RR). Under aqueous electrolytes, however, such charge-enriched active sites can be occupied by adsorbed hydrogen (H∗) and lose their effectiveness for the CO2RR. Here, we develop an efficient catalyst consisting of Cu-doped, defect-rich ZnO (Cu–ZnO) for the CO2RR, which exhibits enhanced CO Faradaic efficiency and current density compared to pristine ZnO. The introduced Cu dopants simultaneously stabilize neighboring oxygen vacancies and modulate their local electronic structure, achieving inhibition of hydrogen evolution and acceleration of the CO2RR. In a flow cell test, a current density of more than 45 ​mA ​cm−2 and a CO Faradaic efficiency of > 80% is obtained for a Cu–ZnO electrocatalyst in the wide potential range of −0.76 ​V to −1.06 ​V vs. Reversible Hydrogen Electrode (RHE). This work opens up great opportunities for dopant-modulated metal oxide catalysts for the CO2RR.