CuO Catalyst Research Articles

Large-Current CO2 Electromethanation Through Active Hydrogen Regulation Over Carbon Nitride.

Electromethanation of CO2 has received intensive attention due to its high calorific value and convenient storage along with transportation to accommodate industrial demands. However, it is limited by sluggish multi-step proton-coupled electron transfer kinetics and undesired *H coupling under high current density, posing great challenges to its commercialization. Herein, carbon nitride (CN) with superior hydrogen adsorption ability is used as an active-hydrogen adsorption and supply material. Through a facile liquid-assisted exfoliation and electrostatic self-assembly strategy to strengthen its interfacial contacts with Cu2O catalysts, yielding a strengthened CH4 production 52 times higher than that of pristine Cu2O. Flow-cell test ultimately achieved FECH4 and remarkably CH4 partial current density of 61% and 561mAcm-2, respectively. With in situ ATR-FTIR spectra and DFT calculations, it is established that strengthened interfaces enabled abundant *H tethered by ─C─N═C─ sites in CN nanosheets and oriented to the *CO hydrogenation to *CHO and *CHx on Cu species. This work reveals the profound influence of fine-expanded interfaces with dimensional materials on the product distribution and yield through the active-hydrogen management, which is of reference value for other small-molecule electro-polarization dominated by the proton-coupled electron transfer (PCET) process (e.g., N2, O2, etc.).

Cotton fabric coated with graphene oxide nanosheets and CuO nanoparticles as a “dip catalyst” for the photocatalytic degradation of dyes

This research focuses on the immobilization in-situ of CuO nanoparticles on graphene oxide nanosheets modified cotton fabric (CuO/GO@CF) for the photodegradation, of organic dyes. The process involves coating the fabrics (CF) with graphene oxide (GO) nanosheets through sonication.The produced CuO, GO@CF, and CuO/GO@CF have been characterized utilizing various physicochemical methods, such as X-ray diffraction (XRD), Fourrier Transformed Infra-Red (FTIR), trans mission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Thermogravimetric analysis (TGA).The catalytic activity of the nanocomposite was assessed by methylene blue (MB) oxidation. Additionally, a detailed analysis was conducted to determine how various parameters, including catalyst surface, pH, MB concentration and CuO loading (%), affected the degradation efficiency. The results showed that the 10 %CuO/5 %GO@CF with a surface of 4 cm2 (2 × 2 cm) exhibited the highest catalytic activity, achieving a MB removal efficiency of 82 % in 90 min. Additionally, after successive reaction cycles, the synthesized composite showed excellent stability and no appreciable drop-in catalytic activity. Moreover, it was shown that the primary reactive oxidative species (ROSs) in charge of the extremely effective MB breakdown were HO.. Lastly, catalyst stability and recyclability showed that CuO/GO@CF might be used as a substitute photocatalyst for environmental cleanup and dye degradation. This synthetized composite can be easily added to and removed from the reaction solution while maintaining high catalytic performance in the removal of dyes and it could be beneficial in avoiding problems related to powder separation.

Bismuth doping unlocks stability of copper oxides in anodic reaction: A case analysis of glucose electrooxidation

The instability of transition metal oxides during long-term electrolysis significantly impedes their application in various electrochemical reactions. This study demonstrates an interfacial doping strategy utilizing bismuth to enhance the stability of CuO catalyst during glucose electrooxidation in alkaline media. This methodology reduces activity decay from 55% to 6% after 8 h of electrolysis, lowering charge transfer resistance without compromising the intrinsic catalytic activity of the Cu sites. The enhanced stability can be attributed to the formation of a Cu−O−Bi interface on the catalyst surface, which mitigates the interfacial Cu dissolution, as evidenced by in situ electrochemical impedance analysis. These findings underscore the potential efficacy of bismuth doping strategies in advancing the development of robust and efficient catalysts for anodic catalysis. Furthermore, this research highlights the prospect of employing main group metals as dopants in transition metal oxides, thereby expanding the horizon of possibilities in catalyst design.

Efficient CO2 reduction to C2 products in a Ce-TiO2 photoanode-driven photoelectrocatalysis system using a Bnanometer Cu2O cathode

Excessive emission of CO2 into the atmosphere has caused significant environmental issues. Photoelectrocatalytic (PEC) reduction of CO2 is an effective method that combines the benefits of both photo- and electrocatalysis. This process effectively minimizes CO2 emissions, enhances the efficiency of CO2 reduction, and diminishes energy consumption during the reduction process. In this work, we have successfully developed a photoelectrochemical (PEC) system, integrating a Ce-doped TiO2 film as the photoanode and Cu2O as the dark cathode, in which the 4 % Ce-TiO2 film photoanode demonstrated the best performance. Electrochemical performance data revealed that the Cu2O catalysts, characterized by their octahedral geometry that optimally presents active sites for CO2 reduction, displayed superior activity in converting CO2. Through a straightforward hydrothermal synthesis, we crafted three-dimensional, flower-like TiO2 thin films. The strategic incorporation of cerium into the TiO2 matrix not only enhanced the material's crystallinity but also resulted in a uniform and compact morphology. This modification significantly narrowed the band gap of TiO2, thereby boosting its photocatalytic capabilities. In the system where a 4 % Ce-TiO2 thin film photoanode was used to drive the PEC reduction of CO2, the octahedral Cu2O catalyst demonstrated the highest selectivity for C2 products. This occurred at a reaction voltage of −1.4 V vs. RHE, resulting in a total Faraday efficiency of 67.33 %. Notably, this Faraday efficiency is double the one produced from the electrocatalytic (EC) system. This work demonstrates that the use of a 4 % Ce-TiO2 film as a photoanode is able to solve the photocorrosion problem of the Cu2O catalyst while employing a photovoltaic combination to enhance the selectivity to C2 products.

Exploring the nature of copper species: CeO2 support shape effect and its influence on CO2 hydrogenation to methanol

A series of CuO catalysts supported on CeO2 with different morphologies (nanorod, nanocube and hydrangea-like) were tested for the CO2 hydrogenation into methanol. Remarkable morphology-dependent CuO-CeO2 interaction was observed, which was associated with the types and concentrations of copper species. The best performance was obtained over the CuO/hydrangea-like-CeO2 catalyst, giving CO2 conversion of 15.6 % and methanol selectivity of 92.4 % at 260 °C and 3 MPa. The enhanced activity was due to the largest amount of small particle size of copper species, which was responsible for the facile activation of H2. Additionally, the Cu2+-Ov-Cex species facilitated the generation of oxygen vacancies and hydroxyl groups, these two species favored formate production and further hydrogenation to methanol. Moreover, in situ diffuse reflectance infrared fourier transform spectroscopy (in situ DRIFTS) results revealed that the both monodentate formate (m-HCOO*) and bidentate formate (bi-HCOO*) were key and necessary intermediate of CO2 hydrogenation to methanol. The proposed predominate reaction pathway was m-HCOO*→ b-*OCH3 → CH3OH and the minor one was bi-HCOO* → t-*OCH3 → CH3OH.

Non-radical activation of persulfate by CuO catalyst for degradation of antibiotics

Advanced oxidation process (AOP) based on persulfate (PS) activation has attracted numerous attentions for antibiotic elimination due to the high stability and low cost of PS. In this work, a non-radical activation of PS by CuO catalyst was developed to efficiently degradation of antibiotics. Employing moxifloxacin (MOX) as model pollutant, the CuO/PS system showed excellent degradation rate for 100 mg L−1 MOX that is 13.2 and 7.7 times higher for than the single CuO and PS, and meanwhile the performance is also much better than the typical AOP heterogeneous catalyst Fe2O3 in both neutral and acidic solutions. The optimization experiments indicate the optimal PS concentration is 2.5 mM, and the CuO/PS system can work in a wide pH range for different MOX concentrations. Furthermore, the CuO catalyst has high structural stability and catalytic durability, and the CuO/PS system has good practicality that can degrade a variety of antibiotics and be used in different aquatic environments. Based on various characterizations, a non-radical PS activation route on the CuO surface was proposed. Finally, toxicity assessment of the detected intermediates implies that the toxicity and the potential risk to the environment were effectively decreased. This work testifies PS can be efficiently activated by CuO through a non-radical pathway and presents superior performance for antibiotic elimination.

Biogenic Synthesis Based on Cuprous Oxide Nanoparticles Using Eucalyptus globulus Extracts and Its Effectiveness for Removal of Recalcitrant Compounds

Recalcitrant compounds resulting from anthropogenic activity are a significant environmental challenge, necessitating the development of advanced oxidation processes (AOPs) for effective remediation. This study explores the synthesis of cuprous oxide nanoparticles on cellulose-based paper (Cu2O@CBP) using Eucalyptus globulus leaf extracts, leveraging green synthesis techniques. The scanning electron microscopy (SEM) analysis found the average particle size 64.90 ± 16.76 nm, X-ray diffraction (XRD) and Raman spectroscopy confirm the Cu2O structure in nanoparticles; Fourier-transform infrared spectroscopy (FTIR) suggests the reducing role of phenolic compounds; and ultraviolet–visible diffuse reflectance spectroscopy (UV-Vis DRS) allowed us to determine the band gap (2.73 eV), the energies of the valence band (2.19 eV), and the conduction band (−0.54 eV) of Cu2O@CBP. The synthesized Cu2O catalysts demonstrated efficient degradation of methylene blue (MB) used as a model as recalcitrant compounds under LED-driven visible light photocatalysis and heterogeneous Fenton-like reactions with hydrogen peroxide (H2O2) using the degradation percentage and the first-order apparent degradation rate constant (kapp). The degradation efficiency of MB was pH-dependent, with neutral pH favoring photocatalysis (kapp = 0.00718 min−1) due to enhanced hydroxyl (·OH) and superoxide radical (O2·−) production, while acidic pH conditions improved Fenton-like reaction efficiency (kapp = 0.00812 min−1) via ·OH. The reusability of the photocatalysts was also evaluated, showing a decline in performance for Fenton-like reactions at acidic pH about 22.76% after five cycles, while for photocatalysis at neutral pH decline about 11.44% after five cycles. This research provides valuable insights into the catalytic mechanisms and supports the potential of eco-friendly Cu2O nanoparticles for sustainable wastewater treatment applications.

High‐efficient electrocatalytic CO2 reduction to HCOOH coupling with 5‐hydroxymethylfurfural oxidation using flow cell

AbstractAmong various products from electrocatalytic CO2 reduction (CO2ER), HCOOH is highly profitable one. However, the slow kinetics of anodic oxygen evolution reaction lowers overall energy efficiency, which can be replaced by an electro‐oxidation reaction with low thermodynamic potential and fast kinetics. Herein, we report an electrolysis system coupling CO2ER with 5‐hydroxymethylfurfural oxidation reaction (HMFOR). A BiOCl–CuO catalyst was designed to sustain CO2ER to HCOOH at partial current density of 500 mA/cm2 with FEHCOOH above 90% and 700 mA/cm2 with FEHCOOH above 80%. In situ and ex situ x‐ray absorption fine structure was used to capture the structure transform of BiOCl–CuO into metallic Bi and Cu during CO2ER process, and the presence of CuO will promote this transformation which are supported by DFT calculations. Coupling HMFOR with CO2ER, we realize both FEHCOOH and FEFDCA above 95% simultaneously, providing new prospects vista for the electrosynthesis of value‐added products from paired system.

Synergistic modulation of valence state and oxygen vacancy induced by surface reconstruction of the CeO2/CuO catalyst toward enhanced electrochemical CO2 reduction

Synergistic modulation of valence state and oxygen vacancy induced by surface reconstruction of the CeO₂/CuO catalyst toward enhanced electrochemical CO₂ reduction

Croton macrostachyus leaf-mediated biosynthesis of copper oxide nanoparticles for enhanced catalytic reduction of organic dyes

Introduction. Owing to the increasing use of organic dyes, the biosynthesis of metal oxide nanocatalysts is urgently needed as an economical and environmentally friendly solution to reduce their waste release. Method. In this study, we synthesized copper oxide nanoparticles (CuO NPs) by the sol–gel method using Croton macrostachyus leaf extracts as capping and reducing agents. The biosynthesized CuO catalysts were characterized using x-ray diffraction analysis (XRD), thermogravimetric differential thermal analysis (TGA-DTA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). Result. The result showed that the synthesized CuO NPs had a crystallite size of about 9 nm and had good crystalline texture. Furthermore, the catalyst showed the best catalytic reduction performance in 1 min for methylene blue (MB) and 3 min for methyl orange (MO). Furthermore, the CuO catalyst synthesized using Croton macrostachyus leaf extract resulted in apparent rate constant (Kapp) values for MB and MO of 0.06793 s−1 and 0.01877 s−1, respectively. Discussion. The recyclability of the CuO catalyst was investigated, and it was shown that the catalysts are suitable for reuse in dye reduction. Therefore, the catalytic activity of this study suggests that the CuO nanocatalysts prepared in this work are a potential candidate for controlling organic pollutants or trace amounts of naturally occurring active organic chemicals in all environmental dye wastes.

Al-doped oxide-derived copper catalyst with stable Cu+ site for efficient electrocatalytic CO2 reduction to C2H4

Electrocatalytic carbon dioxide reduction reaction (ECO2RR), a pivotal process converting CO2 into high-value products, plays a crucial role in advancing objectives of carbon neutrality. Within various catalysts, copper-based electrocatalysts hold a unique position as they demonstrate a remarkable aptitude for producing high-carbon (C2+) products. Notably, the well-established Cu+ sites exhibit robust C-C coupling capabilities, particularly in the synthesis of C2H4 products. However, the challenge lies in maintaining the stability of oxide-derived copper under the negative potential operating conditions. In light of this, we use the ion exchange principle to make Al partially replace Cu-BDC, and then get a dopant by high temperature calcination to prepare Al-doped CuO catalyst. It has been demonstrated that the introduction of oxyphilic Al atoms could induce the redistribution of electrons in the CuO matrix and stabilize the presence of Cu+ in the ECO2RR process. This configuration significantly enhances the catalytic performance of CuO for electrochemically converting CO2 into C2H4. Specifically, the optimized Al-CuO catalyst exhibits ∼50 % Faradaic Efficiency for C2H4 (FEC2H4) at −1.377 V vs. RHE, doubling the performance compared to pure CuO. The design and implementation of doping engineering presented in this work propel advancements in the field of electrocatalytic CO2 reduction for C2H4 production, offering a crucial avenue for the development of efficient catalysts.

Stabilizing Cu0/Cu2+ interface by hydroxy-rich amorphous SiO2 for enhanced electrocatalytic CO2 reduction to ethylene

Constructing a stable Cu0/Cu2+ interface is critical for enhancing the C-C coupling during the process of CO2 electroreduction. However, the high-valence Cu species are unstable under the operating conditions. Herein, polyhedral-shaped CuO is coated with hydroxy-rich SiO2 nanoparticles (m-SiO2/CuO) to stabilize the Cu2+ species, enabling efficient CO2 reduction to the ethylene product. Significantly, the optimal m-SiO2/CuO catalyst exhibits an impressive Faradaic efficiency of 55.5 % and an industrial-level partial current density of 500 mA cm−2 toward ethylene. Fourier transform infrared spectra and X-ray photoelectron spectra reveal that the strong interfacial interaction between CuO and hydroxy-rich SiO2 is conducive to stabilizing the Cu2+ species. In-situ characterizations reveal that the Cu0/Cu2+ interface facilitates CO2 activation and the key intermediate *OCCHO, thus promoting the production of ethylene. This work paves the way for developing advanced electro-catalysts of producing ethylene.

Coupling regulation of boron doping and morphology in nano-floral CuO using one pot method for electrocatalytic CO2 reduction

The two crucial methods for regulating Cu-based electrocatalysts to achieve high C2+ selectivity during CO2 reduction are doping with heteroatoms and controlling morphology. However, it is challenging to achieve both through the facial preparation approach. Herein, we prepared a series of nano-floral boron-doped CuO catalysts by a simple one-pot template-free approach to attain the coupling regulation of boron doping and morphology by the amount of H3BO3 added. As indicated by the SEM and TEM results, these petals of B3-CuO are the sharpest and the overall size is the smallest among all the nano-floral catalysts, enabling them to demonstrate a tip effect. B3-CuO exhibits enhanced electron transport capacity and a more pronounced response to CO2, aligning with its electrochemical characteristics. Meanwhile, B3-CuO possesses higher Vo compared to other catalysts. These factors lead to B3-CuO having the greatest FEC2H4 at −1.2 V vs. RHE, reaching 51.2 %, and excellent stability. The possible reaction pathway of Bx-CuO has been elucidated through in-situ ATR-SEIRAS, which indicates that the mechanism involves CO2→*COOH→*CO→*OCCOH → C2H4. Therefore, the coupled use of B-doped and morphology regulation offers a notable improvement in C2H4 selectivity while unlocking asymmetric C–C coupled pathways towards higher FEC2H4.

Bottom‐up Growth of Convex Sphere with Adjustable Cu(0)/Cu(I) Interfaces for Effective C2 Production from CO2 Electroreduction

AbstractOne challenge confronting the Cu2O catalysts in the electrocatalysis of carbon dioxide reduction reaction (CO2RR) is the reduction of active Cu(I) species, resulting in low selectivity and quick deactivation. In this study, we for the first time introduce a bottom‐up growth of convex sphere with adjustable Cu(0)/Cu(I) interfaces (Cux@Cu2O convex spheres). Interestingly, the interfaces are dynamically modulated by varying hydrothermal time, thus regulating the conversion of C1 and C2 products. In particular, the 4 h hydrothermal treatment applied to Cu0.25@Cu2O convex sphere with the favorable Cu(0)/Cu(I) interface results in the highest selectivity for C2 products (90.5 %). In situ Fourier‐transform infrared spectroscopy measurements and density functional theory calculations reveal that the Cu(0)/Cu(I) interface lowers the energy barrier for the production of ethylene and ethanol while increasing the coverage of localized *CO adsorbate for increased dimerization. This work establishes a novel approach for transforming the state of valence‐sensitive electrocatalysts into high‐value energy‐related engineering products.

Bottom-up Growth of Convex Sphere with Adjustable Cu(0)/Cu(I) Interfaces for Effective C2 Production from CO2 Electroreduction.

One challenge confronting the Cu2O catalysts in the electrocatalysis of carbon dioxide reduction reaction (CO2RR) is the reduction of active Cu(I) species, resulting in low selectivity and quick deactivation. In this study, we for the first time introduce a bottom-up growth of convex sphere with adjustable Cu(0)/Cu(I) interfaces (Cux@Cu2O convex spheres). Interestingly, the interfaces are dynamically modulated by varying hydrothermal time, thus regulating the conversion of C1 and C2 products. In particular, the 4 h hydrothermal treatment applied to Cu0.25@Cu2O convex sphere with the favorable Cu(0)/Cu(I) interface results in the highest selectivity for C2 products (90.5%). In situ Fourier-transform infrared spectroscopy measurements and density functional theory calculations reveal that the Cu(0)/Cu(I) interface lowers the energy barrier for the production of ethylene and ethanol while increasing the coverage of localized *CO adsorbate for increased dimerization. This work establishes a novel approach for transforming the state of valence-sensitive electrocatalysts into high-value energy-related engineering products.

Waste Biomass-Derived Activated Carbon-Supported 0D, 1D, 2D, and 3D Nanostructures of Copper Oxide for Hydrogenation Reaction: A Study on the Role of Structural Properties.

Intensive attention is given to the morphology-controlled synthesis of inorganic nanomaterials because of their intrinsic shape-dependent properties. In this article, different dimensions (D) of copper oxide (CuO) nanoparticles (such as 0D-sphere, 1D-rod, 1D-belt, 2D-rolling pin sheets, 3D-octahedron, and 3D-throne) are prepared. The catalytic efficacy of these differently shaped CuO catalysts is compared for hydrogenation reactions under reducing agent-free conditions. The order of catalytic activity of the CuO catalyst is found to be belt > octahedron > rolling pin > rod > sphere > throne. The best catalyst among the different shaped CuO catalysts, namely belt shape, is supported on the functionalized groundnut shells activated carbon sheets (FGNC). Interestingly, 25 wt % CuO/FGNC catalysts exhibit the highest catalytic activity for the reduction of nitro compounds. Importantly, the highly active FGNC-supported catalyst is reused for up to 10 cycles without any noticeable loss in the catalytic activity.

XPS valence band observable light-responsive system for photocatalytic acid Red114 dye decomposition using a ZnO–Cu2O heterojunction

ZnO–Cu2O composites were made as photocatalysts in a range of different amounts using an easy, cheap, and environment-friendly coprecipitation method due to their superior visible light activity to remove pollutants from the surrounding atmosphere. X-ray diffraction and Fourier transform infrared spectroscopy (FT-IR) have demonstrated that ZnO–Cu2O catalysts are made of highly pure hexagonal ZnO and cubic Cu2O. X-ray photoelectron spectroscopy has confirmed that there is a substantial interaction between the two phases of the resultant catalyst. The optical characterizations of the synthesized ZnO–Cu2O composite were done via UV–vis reflectance spectroscopy. Due to the doping on ZnO, the absorption range of the ZnO–Cu2O catalyst is shifted from the ultraviolet to the visible region due to diffuse reflection. The degradation efficiency is affected by the Ratio of ZnO: Cu2O and ZnO–Cu2O composite with a proportion of 90:10 exhibited the most prominent photocatalytic activity on Acid Red 114, with a pseudo-first-order rate constant of 0.05032 min−1 that was 6 and 11 times greater than those of ZnO and Cu2O, respectively. The maximum degradation efficiency is 97 %. The enhanced photocatalytic activity of the composite is caused by the synergistic interaction of ZnO and Cu2O, which improves visible light absorption by lowering band gap energy and decreasing the rate at which the electron-hole pairs recombine. The scavenging experiment confirmed that hydroxyl radical was the dominant species for the photodegradation of Acid Red 114. Notably, the recycling test demonstrated the ZnO–Cu2O photocatalyst was highly stable and recyclable. These results suggest that the ZnO–Cu2O mix might be able to clean up environmental pollutants when it meets visible light.

Boosting the electroreduction of CO2 to liquid products via nanostructure engineering of Cu2O catalysts

The electrochemical reduction of CO2 presents a promising pathway for storing intermittent renewable energy in the form of chemical bonds, thereby mitigating CO2 emissions and enabling the production of sustainable fuels. In this work, we demonstrate nanoscale engineering of oxygen vacancy and morphology simultaneously on Cu2O catalysts for electrochemical reduction of CO2 to liquid products (formate and ethanol). By comparing the performance of cube- and tetrakaidecahedron-like Cu2O catalysts, we have demonstrated that the flower-like Cu2O catalyst, enclosed with rich oxygen vacancy defects, exhibited superior performance in the reduction of CO2 to liquid products. Moreover, the synergetic role of Cu+ also contributed to the enhanced activity by promoting CO2 adsorption and facilitating C–C coupling. As a result, the peak Faradaic efficiency (FE) for liquid products of 95.5 % was obtained, associated with a high ethanol FE of 52.6 % and formation rate of 23.8 μmol h−1 cm−2 within a H-cell. Furthermore, within a flow cell configuration, we have observed a significant improvement in the generation of formate, maintaining FE values above 70 % even under high current densities of up to 400 mA cm−2. In-situ Raman spectroscopic measurements allow us to identify and track key intermediates involved in the CO2 reduction to formate and ethanol. This detailed understanding of the reaction pathways adds to our fundamental knowledge and provides valuable insights for the development of morphology-controlled electrocatalysts targeting efficient conversion of CO2 into liquid products.

N-doped Cu2O with the tunable Cu0 and Cu+ sites for selective CO2 electrochemical reduction to ethylene

The electrochemical carbon dioxide reduction reaction (CO2RR) to high value-added fuels or chemicals driven by the renewable energy is promising to alleviate global warming. However, the selective CO2 reduction to C2 products remains challenge. Cu-based catalyst with the specific Cu0 and Cu+ sites is important to generate C2 products. This work used nitrogen (N) to tune amounts of Cu0 and Cu+ sites in Cu2O catalysts and improve C2-product conversion. The controllable Cu0/Cu+ ratio of Cu2O catalyst from 0.16 to 15.19 was achieved by adjusting the N doping amount using NH3/Ar plasma treatment. The major theme of this work was clarifying a volcano curve of the ethylene Faraday efficiency as a function of the Cu0/Cu+ ratio. The optimal Cu0/Cu+ ratio was determined as 0.43 for selective electroreduction CO2 to ethylene. X-ray spectroscopy and density functional theory (DFT) calculations were employed to elucidate that the strong interaction between N and Cu increased the binding energy of NCu bond and stabilize Cu+, resulting in a 92.3% reduction in the potential energy change for *CO-*CO dimerization. This study is inspiring in designing high performance electrocatalysts for CO2 conversion.

Ulva lactuca L. extract bio-templated fabrication of CuO/ZnFe2O4 nanocomposites for photodegradation organic dye pollutants and in vitro biological activities

In this present work, a novel CuO/ZnFe2O4 nanocomposites has been fabricated via hydrothermal-assisted synthesis using Ulva lactuca L. extract as both a reducing and capping agent A comprehensive investigation such as structural, morphological, optical, and electronic properties of the CuO/ZnFe2O4 NCs were investigated in details. The photocatalytic efficacy of the prepared CuO/ZnFe2O4 NCs was assessed for Congo red (CR) dye degradation and the experimental results demonstrate the CuO/ZnFe2O4 NCs exhibits superior photocatalytic activity (91.13% k=0.03289 min−1) compared to pure CuO and ZnFe2O4 catalysts under 120 min of visible light irradiation. Additionally, the CuO/ZnFe2O4 NCs exhibited excellent long-term recycling stability over four consecutive cycles. This enhanced photocatalytic performance of CuO/ZnFe2O4 NCs was attributed to the synergism between CuO and ZnFe2O4, which facilitate the exceptional properties such as large specific area, a wide visible-light absorption range, and efficient electron-hole separation. Furthermore, the prepared CuO/ZnFe2O4 NCs were evaluated for their in vitro antibacterial and anticancer properties. The results of the disc diffusion assay with CuO/ZnFe2O4 NCs as an antibacterial agent demonstrated a highest zone of inhibition of 18.23 ± 0.30 mm for Bacillus subtilis and 19.83 ± 0.76 mm Escherichia coli. Moreover, in vitro cytotoxicity assessments using the MTT assay indicated a 64.94% cytotoxic activity against HT-29 colon cancer cells. The multifunctional advantages of Ulva lactuca L. extract-mediated green CuO/ZnFe2O4 NCs hold significant promise for environmental remediation and in vitro-based therapeutic applications.