Development of CuAg/Cu2O nanoparticles on carbon nitride surface for methanol oxidation and selective conversion of carbon dioxide into formate

Jute-Copper Nanocomposite Embedded PSf Membrane for Sustainable and Efficient Heavy Metal Removal from Water Sources

Numerous corporations have overlooked environmental regulations concerning wastewater treatment, leading to a worldwide issue regarding hazardous pollutant discharge, particularly dyes and heavy metal ions, into river sources. Various industries, with water, energy, and biological sectors, actively employ membranes. Membranes capable of showing flux, metal and dye sorption, and catalysis have been developed and are extensively used by functionalizing the pores of ultrafiltration, microfiltration, and nanofiltration membranes with responsive properties. The enhancement of synthetic membrane performance can be achieved by developing new polymers or modifying the surface of existing polymers. In this study, high porosity and large internal pore volume polysulfone (PSf) membrane composites were produced on a laboratory scale by adjusting the polymer coagulation conditions during the phase inversion process, incorporating copper nanoparticles for antifouling properties, and utilizing pretreated natural jute fibers. A comprehensive characterization of the composites was conducted by using FTIR, XRD, XPS, ICP-MS, and SEM techniques. To calculate their possible uses in separation and purification methods, the performance of PSf-based membrane composites was evaluated in terms of heavy metal rejection rates (%) in water.

Construction synergetic adsorption and activation surface via confined Cu/Cu2O and Ag nanoparticles on TiO2 for effective conversion of CO2 to CH4

High-performance photocatalysts for catalytic reduction of CO2 are largely impeded by inefficient charge separation and surface activity. Reasonable design and efficient collaboration of multiple active sites are important for attaining high reactivity and product selectivity. Herein, Cu-Cu2O and Ag nanoparticles are confined as dual sites for assisting CO2 photoreduction to CH4 on TiO2. The introduction of Cu-Cu2O leads to an all-solid-state Z-scheme heterostructure on the TiO2 surface, which achieves efficient electron transfer to Cu2O and adsorption and activation of CO2. The confined nanometallic Ag further enhances the carrier's separation efficiency, promoting the conversion of activated CO2 molecules to •COOH and further conversion to CH4. Particularly, this strategy is highlighted on the TiO2 system for a photocatalytic reduction reaction of CO2 and H2O with a CH4 generation rate of 62.5 μmol∙g-1∙h-1 and an impressive selectivity of 97.49 %. This work provides new insights into developing robust catalysts through the artful design of synergistic catalytic sites for efficient photocatalytic CO2 conversion.

Two-way rushing travel: Cathodic-anodic coupling of Bi2O3-SnO@CuO nanowires, a bifunctional catalyst with excellent CO2RR and MOR performance for the efficient production of formate

Electrocatalytic carbon dioxide reduction reaction (CO2RR) generates high value-added products and simultaneously reduces excess atmospheric CO2 concentrations, is regarded as a potential approach to achieve carbon neutrality. However, the kinetic process of the anode oxygen evolution reaction (OER) is slow, resulting in a poor electrochemical efficiency of CO2RR. It is a breakthrough to replace OER with methanol oxidation reaction (MOR), which has more advantageous reaction kinetics. Herein, this work proposed a bifunctional catalyst Bi2O3-SnO modified CuO nanowires (Bi2O3-SnO@CuO NWs) with excellent CO2RR and MOR performance. For CO2RR, Bi2O3-SnO@CuO NWs achieved more than 90% formate selectivity at wide potential windows from -0.88 to -1.08 V (vs. reversible hydrogen electrode (RHE)), peaking at 96.6%. Meanwhile, anodic Bi2O3-SnO@CuO NWs achieved 100 mA cm-2 at a low potential of 1.53 V (vs. RHE), possessing nearly 100% formate selectivity ranging from 1.6 to 1.8 V (vs. RHE). Impressively, by coupling cathodic CO2RR and anodic MOR, the integrated electrolytic cell realized co-production of formate (cathode: 94.7% and anode: 97.5%), minimizing the energy input by approximately 69%, compared with CO2RR. This work provided a meaningful perspective for the design of bifunctional catalysts and coupling reaction systems in CO2RR.

Nanofibrous Dressing with Nanocomposite Monoporous Microspheres for Chemodynamic Antibacterial Therapy and Wound Healing

The excessive use of antibiotics and consequent bacterial resistance have emerged as crucial public safety challenges for humanity. As a promising antibacterial treatment, using reactive oxygen species (ROS) can effectively address this problem and has the advantages of being highly efficient and having low toxicity. Herein, electrospinning and electrospraying were employed to fabricate magnesium oxide (MgO)-based nanoparticle composited polycaprolactone (PCL) nanofibrous dressings for the chemodynamic treatment of bacteria-infected wounds. By utilizing electrospraying, erythrocyte-like monoporous PCL microspheres incorporating silver (Ag)- and copper (Cu)-doped MgO nanoparticles were generated, and the unique microsphere-filament structure enabled efficient anchoring on nanofibers. The composite dressings produced high levels of ROS, as confirmed by the 2,7-dichloriflurescin fluorescent probe. The sustained generation of ROS resulted in efficient glutathione oxidation and a remarkable bacterial killing rate of approximately 99% against Staphylococcus aureus (S. aureus). These dressings were found to be effective at treating externally infected wounds. The unique properties of these composite nanofibrous dressings suggest great potential for their use in the medical treatment of bacteria-infected injuries.

Self-assembled supramolecule for synthesizing highly thermally conductive Cellulose/Carbon nitride nanocomposites with improved flame retardancy

The fabrication of polymer composites with excellent thermal conductivity typically involves complex matrix or fillers modifications. This study proposed a simple technique based on precursor selection for obtaining highly thermally conductive cellulose nanofiber (CNF)/supramolecule-synthesized carbon nitride (SCN) composites. Fourier-transform infrared tests demonstrated the construction of hydrogen bonds between CNF and SCN; a highly ordered structure and relatively compact in-plane stacking were confirmed via scanning electron microscopy and X-ray diffraction characterizations. Consequently, the resultant CNF/SCN composites exhibited remarkable in-plane thermal conductivity of 11.83 ± 0.41 W m^-1 K^-1 at 30 wt% SCN content, which was attributed to the significantly reduced interfacial phonon scattering. It also showed evident improvements in electrical insulation and flame retardancy compared with the pure CNF film, where the volume resistivity, peak heat release rate, and total heat release were remarkably enhanced by 1242% and reduced by 59.9% and 15.8%, respectively. Further analysis of char residuals revealed a relatively dense surface, high concentration of carbon materials, and a high degree of graphitization, indicating that the char residual functioned as a robust physical barrier to effectively inhibit combustion. This study provides a facile approach to achieving high-efficiency improvements in thermal conductivity and flame retardancy, and simultaneously facilitating broader applications of carbon nitride in thermal management.

Integrated catalytic insights into methanol production: Sustainable framework for CO2 conversion

A continuous increase in the amount of greenhouse gases (GHGs) is causing serious threats to the environment and life on the earth, and CO₂ is one of the major candidates. Reducing the excess CO₂ by converting into industrial products could be beneficial for the environment and also boost up industrial growth. In particular, the conversion of CO₂ into methanol is very beneficial as it is cheaper to produce from biomass, less inflammable, and advantageous to many industries. Application of various plants, algae, and microbial enzymes to recycle the CO₂ and using these enzymes separately along with CO₂-phillic materials and chemicals can be a sustainable solution to reduce the global carbon footprint. Materials such as MOFs, porphyrins, and nanomaterials are also used widely for CO₂ absorption and conversion into methanol. Thus, a combination of enzymes and materials which convert the CO₂ into methanol could energize the CO₂ utilization. The CO₂ to methanol conversion utilizes carbon better than the conventional syngas and the reaction yields fewer by-products. The methanol produced can further be utilized as a clean-burning fuel, in pharmaceuticals, automobiles and as a general solvent in various industries etc. This makes methanol an ideal fuel in comparison to the conventional petroleum-based ones and it is advantageous for a safer and cleaner environment. In this review article, various aspects of the circular economy with the present scenario of environmental crisis will also be considered for large-scale sustainable biorefinery of methanol production from atmospheric CO₂.

Rational design of Cu3PdN nanocrystals for selective electroreduction of carbon dioxide to formic acid

The selective electrochemical reduction of CO₂ yields value-added products that are important renewable energy resources for carbon recycling. In this study, Cu₃PdN nanocrystals (NCs) exhibited higher electrocatalytic activity for carbon dioxide (CO₂) reduction to formic acid (HCOOH) than as-prepared Cu₃N and Cu₃Pd NCs. In addition, the reaction yielded small amounts of CO (<5%), H₂, and HCOOH as the main products, and the electrocatalytic activity of the Cu NCs was significantly enhanced by modification with N and Pd. This work demonstrates a simple and effective strategy for improving the electrochemical reduction of CO₂.

Nanosheet Synthesis of Mixed Co3O4/CuO via Combustion Method for Methanol Oxidation and Carbon Dioxide Reduction

This paper represents a study of mixed Co₃O₄/CuO nanosheet (NS) synthesis via solution combustion synthesis for oxidation of methanol and carbon dioxide (CO₂) conversion. The mixed oxide NS of Co₃O₄/CuO is a hybrid structure of Co₃O₄ and CuO NSs. We applied this mixed oxide NS of Co₃O₄/CuO for methanol oxidation and carbon dioxide (CO₂) conversion, and the results revealed that the activity of the mixed oxide NS surpassed the activity of the corresponding individual Co₃O₄ and CuO metal oxide NSs, both in methanol oxidation and in CO₂ conversion. The mass activity of the mixed Co₃O₄/CuO NS produced at 0.627 V versus Ag/AgCl during methanol oxidation (0.5 M) was 12 mA g^-1, which is 2.4 times better than that of Co₃O₄, whose mass activity is 5 mA g^-1, and 4 times better than that of the CuO NS, whose mass activity is 3 mA g^-1. The methanol oxidation peak at 0.62 V versus Ag/AgCl was also more intense than individual oxides. The trend in performance of methanol oxidation follows the order: Co₃O₄/CuO > Co₃O₄ > CuO. In the case of CO₂ reduction, we experienced that our product was formate, and this was proved by formate oxidation (formate is formed as a product during the reduction of CO₂) on the surface of the Pt ring of a rotating ring-disc electrode. Similar to methanol oxidation, Co₃O₄/CuO also showed superior activity in carbon dioxide reduction. It was experienced that at -1.5 V, the current density rises to -24 mA/cm² for the Co₃O₄/CuO NS, that is, 0.6 times that of the CuO NS, which is -15 mA/cm², and 3 times more than that of the Co₃O₄ NS, which is 8 mA/cm². The trend in performance of CO₂ reduction follows the order: Co₃O₄/CuO > CuO > Co₃O₄.