Search Results (1,358)

Growing interest in sustainable hydrogen production has brought renewed attention to photoelectrochemical (PEC) water splitting as a promising route for direct solar-to-chemical energy conversion. This study explores how integrating hematite (α-Fe₂O₃) and cupric oxide (CuO) photoelectrodes with a series of nickel-based co-catalysts can improve photoelectrochemical activity. Photoanodic (NiO_x, NiFeO_x, NiWO₄) and photocathodic (Ni, NiCu, NiMo) co-catalysts were synthesized via co-precipitation and mechanochemical methods and characterized through X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Transmission Electron Microscopy–Energy Dispersive X-ray Spectroscopy (TEM-EDX), Scanning Electron Microscopy–Energy Dispersive X-ray Spectroscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) gas-adsorption analyses to clarify their crystallographic, morphological, and compositional properties, as well as their surface chemistry and textural properties (surface area and porosity). Electrochemical tests under 1 SUN illumination showed that NiO_x significantly improves the photocurrent of hematite photoanodes. Among the cathodic co-catalysts, NiMo demonstrated the best performance when combined with CuO photocathodes. For both photoelectrodes, an optimal co-catalyst loading was identified, beyond which performance declined due to potential charge transfer limitations and light attenuation. These findings highlight the critical role of co-catalyst composition and loading in optimizing the efficiency of PEC systems based on earth-abundant materials, offering a pathway toward scalable and cost-effective hydrogen production. Full article

CO₂ hydrogenation to methanol has attracted considerable attention as a promising catalytic route for both reducing CO₂ emissions and producing valuable chemical intermediates. Among various catalysts, Cu–ZnO-based systems are the most widely studied; however, their performance remains constrained by limited methanol selectivity and stability, highlighting the need for improved catalytic strategies. In this work, liquid metal gallium (Ga) was incorporated into Cu–ZnO catalysts as an additive for CO₂ hydrogenation to methanol. Owing to its high dispersibility and fluidity, Ga helps maintain long-term catalyst stability. We investigated different introduction methods for Ga promoters and found that the physical mixing approach generated the strongest alkaline sites, thereby enhancing CO₂ activation and increasing the CO₂ conversion to methanol. Moreover, this catalyst effectively suppressed carbon deposition, further improving its stability. These findings offer new insights into the use of liquid metal Ga in CO₂ hydrogenation and provide fresh perspectives for the rational design of efficient methanol synthesis catalysts. Full article

Understanding how solvents influence the luminescence behavior of Cu(I) complexes is crucial for designing advanced optical sensors. This study reports the synthesis, structures and photophysical investigation of an 8-hydroxyquinoline-functionalized 1H-imidazo[4,5-f][1,10]phenanthroline ligand, ipqH₂, and its four Cu(I) complexes with diphosphine co-ligands. Photoluminescence studies demonstrated distinct solvent-dependent excited-state mechanisms. In DMSO/alcohol mixtures, free ipqH₂ exhibited excited-state proton transfer (ESPT) and enol-keto tautomerization, producing dual emission at about 447 and 560 nm, while the complexes resisted ESPT due to hydrogen bond blocking by PF₆⁻ anions and Cu(I) coordination. In DMSO/H₂O, aggregation-caused quenching (ACQ) and high-energy O–H vibrational quenching dominated, but complexes 1 and 2 showed a significant red-shifted emission (569–574 nm) with high water content due to solvent-stabilized intra-ligand charge transfer and metal-to-ligand charge transfer ((IL+ML)CT) states. In DMSO/DMF, hydrogen bond competition and solvation-shell reorganization led to distinct responses: complexes 1 and 3, with flexible bis[(2-diphenylphosphino)phenyl]ether (POP) ligands, displayed peak splitting and (IL + ML)CT redshift emission (501 ⟶ 530 nm), whereas complexes 2 and 4, with rigid 9,9-dimethyl-4,5-bis(diphenylphosphino)-9H-xanthene (xantphos), showed weaker responses. The flexibility of the diphosphine ligand dictated DMF sensitivity, while the coordination, the hydrogen bonds between PF₆⁻ anions and ipqH₂, and water solubility governed the alcohol/water responses. This work elucidates the multifaceted solvent-responsive mechanisms in Cu(I) complexes, facilitating the design of solvent-discriminative luminescent sensors. Full article

Electrochemical CO₂ reduction reaction (CO₂RR) is a key technology for achieving carbon neutrality and efficient utilization of renewable energy, capable of converting CO₂ into high-value-added carbon-based fuels and chemicals. Copper (Cu)-based catalysts have attracted significant attention due to their unique performance in generating multi-carbon (C₂₊) products such as ethylene and ethanol; however, there are still many controversies regarding their complex reaction mechanisms, active sites, and the dynamic evolution of intermediates. In situ Raman spectroscopy, with its high surface sensitivity, applicability in aqueous environments, and precise detection of molecular vibration modes, has become a powerful tool for studying the structural evolution of Cu catalysts and key reaction intermediates during CO₂RR. This article reviews the principles of electrochemical in situ Raman spectroscopy and its latest developments in the study of CO₂RR on Cu-based catalysts, focusing on its applications in monitoring the dynamic structural changes of the catalyst surface (such as Cu⁺, Cu⁰, and Cu²⁺ oxide species) and identifying key reaction intermediates (such as *CO, *OCCO(*O=C-C=O), *COOH, etc.). Numerous studies have shown that Cu-based oxide precursors undergo rapid reduction and surface reconstruction under CO₂RR conditions, resulting in metallic Cu nanoclusters with unique crystal facets and particle size distributions. These oxide-derived active sites are considered crucial for achieving high selectivity toward C₂₊ products. Time-resolved Raman spectroscopy and surface-enhanced Raman scattering (SERS) techniques have further revealed the dynamic characteristics of local pH changes at the electrode/electrolyte interface and the adsorption behavior of intermediates, providing molecular-level insights into the mechanisms of selectivity control in CO₂RR. However, technical challenges such as weak signal intensity, laser-induced damage, and background fluorescence interference, and opportunities such as coupling high-precision confocal Raman technology with in situ X-ray absorption spectroscopy or synchrotron radiation Fourier transform infrared spectroscopy in researching the mechanisms of CO₂RR are also put forward. Full article

Copper and iron species were co-deposited onto a hydroxyapatite surface to produce bimetallic catalysts. Characterization techniques (XRD, XPS, DR-UV spectroscopy and TEM-EDX) helped in unveiling the speciation, nuclearity, and electronic properties of copper and iron in samples with variable total metal loading (1–10 wt.%) and relative Cu-to-Fe ratios. The speciation of Cu was revealed to be not affected by Fe and vice versa. Conversely, the metal loading turned out to be a key factor ruling the aggregation state of Cu and Fe species. The samples were tested as catalysts in the Selective Catalytic Reduction of NO by NH₃ (NH₃-SCR) in dry and wet environments under quasi-real conditions (50,000 ppm O₂; 50,000 ppm H₂O, if present; 120,000 h⁻¹ GHSV) in the 200−500 °C interval. Although the combination of Cu and Fe affords a modest improvement in water resistance compared to their monometallic counterparts, no substantial enhancement in activity was observed for the bimetallic hydroxyapatite-based SCR catalysts. Full article

The success of mRNA-based SARS-CoV-2 vaccines has been confirmed in both preclinical and clinical settings. However, the development of safe and efficient mRNA vaccine delivery platforms remains challenging. In this report, PBAE-G-B-SS-modified CaO₂ nanofibers and Au@OVA@Cu@Dendrobium huoshanense polysaccharides were employed to establish novel self-assembling polymeric micelles (CaO₂@Au@OVA@Cu@DHPs) capable of serving as both an adjuvant and a delivery system for mRNA vaccines. In vitro, CaO₂@Au@OVA@Cu@DHPs nanoparticles (NPs) were conducive to effective macrophage antigen uptake and efficient antigen processing. In vivo, P-CaO₂@Au@OVA@Cu@DHPs NP administration was associated with a reduction in the ovalbumin (OVA) release rate that was conducive to the sustained induction of long-term immunity and to the production of higher levels of different IgG subtypes, suggesting that these effects were attributable to enhanced antigen uptake by antigen-presenting cells. Overall, these present data highlight the promise of these P-CaO₂@Au@OVA@Cu@DHPs NPs as an effective and safe platform amenable to vaccine delivery through their ability to provide robust adjuvant activity and sustained antigen release capable of eliciting long-term immunological memory while potentiating humoral and cellular immune responses. Full article

Aqueous zinc-ion batteries (AZIBs) have attracted significant attention for large-scale energy storage owing to their high safety, low cost, and environmental friendliness. However, issues such as dendrite growth, hydrogen evolution, and corrosion at the zinc anode severely limit their cycling stability. In this study, a “synergistic solvation shell–interfacial adsorption regulation” strategy is proposed, employing potassium gluconate (KG) and dimethyl sulfoxide (DMSO) as composite additives to achieve highly reversible zinc anodes. DMSO integrates into the Zn²⁺ solvation shell, weakening Zn²⁺-H₂O interactions and suppressing the activity of free water, while gluconate anions preferentially adsorb onto the zinc anode surface, inducing the formation of a robust solid electrolyte interphase (SEI) enriched in Zn(OH)₂ and ZnCO₃. Nuclear magnetic resonance(NMR), Raman, and Fourier transform infrared spectroscopy(FTIR) analyses confirm the reconstruction of the solvation structure and reduction in water activity, and X-ray photoelectron spectroscopy(XPS) verifies the formation of the SEI layer. Benefiting from this strategy, Zn||Zn symmetric cells exhibit stable cycling for over 1800 h at 1 mA cm⁻² and 1 mAh cm⁻², and Zn||Cu cells achieve an average coulombic efficiency of 96.39%, along with pronounced suppression of the hydrogen evolution reaction. This work provides a new paradigm for the design of low-cost and high-performance electrolyte additives. Full article

In the present study three composite materials based on iron in combination with bismuth, copper or lithium carbonates FeNO₃@Li₂CO₃ (SFL), FeNO₃@CuCO₃ (SFC), and FeNO₃@(BiO)₂CO₃ (SFB) were synthesized by coprecipitation. The purpose was to obtain materials that possess targeted adsorbent properties for the recovery of silver ions from aqueous solutions. After synthesis, to emphasize the adsorptive qualities of materials for the recovery of silver ions, the synthesized composite materials, as well as those doped with silver ions following the adsorption process (SFL-Ag, SFC-Ag, and SFB-Ag), were characterized and several adsorption-specific parameters were examined, including temperature, contact time, pH, adsorbent dose, and the initial concentration of silver ions in solution. Subsequently, the ideal adsorption conditions were determined to be as follows: pH > 4, contact time 60 min, temperature 298 K, and solid–liquid ratio (S–L) of 0.1 g of adsorbent to 25 mL of Ag (I) solution for all three materials. The Langmuir model properly fits the experimental equilibrium data of the adsorption process; however, the Ho–McKay model closely represents the adsorption kinetics. The maximum adsorption capacities of the materials, 19.7 mg Ag(I)/g for SFC, 19.3 mg Ag(I)/g for SFB, and 19.9 mg Ag(I)/g for SFL, are comparable. The adsorption mechanism is physical in nature, as evidenced by the activation energies of 1.6 kJ/mol for SFC, 4.15 kJ/mol for SFB, and 1.32 kJ/mol for SFL. The highest Ag(I) concentration used for doping all three materials in the study was 150 mg Ag(I)/L. The process is endothermic, spontaneous, and takes place at the interface between the adsorbent and the adsorbate, according to thermodynamic theory. Subsequently, the antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans microorganisms was evaluated by rate of inhibition assessment. The SFC-Ag material showed a percentage of 100% inhibition with respect to the positive control for each microorganism. All synthetized materials have better efficiency as antifungal agents. Full article

Herein, nanoscale MgAl₂O₄ (MOA), 10%CuO@MgAl₂O₄ (10Cu@MOA), 10%NiO@MgAl₂O₄ (10Ni@MOA), and 10%CoO@MgAl₂O₄ (10Co@MOA) were synthesized employing butylated hydroxytoluene (the food additive BHT) as a capping agent. The SEM images illustrated average sizes of 38.8, 30.0, 40.8, and 32.7 nm for MOA, 10Cu@MOA, 10Ni@MOA, and 10Co@MOA, respectively, and their BET surface area were 84.4, 141.8, 126.7, and 105.3, respectively. Doxycycline DXC removal was studied employing the MOA, 10Cu@MOA, 10Ni@MOA, and 10Co@MOA, which resulted in q_t values of 57.3, 106.1, 97.7, and 73.9 mg g⁻¹, respectively. The pseudo-second order model best described the DXC sorption onto MOA, 10Cu@MOA, 10Ni@MOA, and 10Co@MOA, and both film diffusion models influenced the DXC sorptions onto the sorbents. The DXC sorption onto the 10Cu@MOA fitted the Freundlich model. The thermodynamics implied endothermic-spontaneous DXC sorption onto the10Cu@MOA. The pH study exposed that the DXC removal by 10Cu@MOA was more effective in a mildly acidic medium (pH = 6.0). Furthermore, the 10Cu@MOA effectiveness in treating surface water contaminated by 5.0 and 10.0 mg L⁻¹ DXC was 99.9% and 98.1%, respectively, while it was 94.7% and 92.5% in treating the concentrations above in seawater, respectively. The reusability study showed a 10% reduction in the 10Cu@MOA’s removal efficiency at the fourth cycle, which is encouraging for real-life applications. Full article

Two copper-containing perovskites Ba_0.8Mn_0.7Cu_0.3O₃ and Cu(4 wt%)/Ba_0.7MnO₃ (selected from previous studies) were tested as catalysts for the CO oxidation reaction under conditions similar to the found in the exhaust of last-generation automotive internal combustion engines. The Cu(4 wt%)/Ba_0.7MnO₃ sample has been selected due to its higher tolerance to CO₂. In order to optimize the performance of this sample for the reaction under study, a Cu(2 wt%)Ce(2 wt%)/Ba_0.7MnO₃ formulation was synthesized, characterized and tested. The excellent catalytic performance of the bimetallic formulation, in terms of CO conversion at low temperatures and tolerance to CO₂, is because cerium improves the redox properties and increases the proportion of reduced copper species on the surface compared to the Cu(4 wt%)/Ba_0.7MnO₃ sample. Full article

The alarming rise in foodborne illnesses, particularly those associated with microbial contamination in meat products, presents a serious challenge to global food safety. Among these microbial threats, Pseudomonas aeruginosa (P. aeruginosa) poses a critical threat due to its biofilm-forming capability and prevalence in contaminated beef, highlighting its effective real-time detection. Herein, we report the fabrication of a novel electrochemical aptasensor based on multimetal perovskite (FeCoCuNiO) doped with urea-derived graphitic carbon nitride (g-C₃N₄), synthesized via a sol–gel combustion method. The FeCoCuNiO-g-C₃N₄ nanocomposite was then coated onto a graphitic pencil electrode and functionalized with a DNA-based aptamer specific towards P. aeruginosa. The resulting aptasensor exhibited a low detection limit of 3.03 CFU mL⁻¹ with high selectivity and sensitivity, and was successfully applied to real-time detection of P. aeruginosa in food samples. To the best of our knowledge, this work presents the first FeCoCuNiO-g-C₃N₄-based aptasensor for bacterial detection, offering a promising platform for food safety assurance and public health protection. Full article

The incomplete degradation of degradable plastics may pose potential ecological risks, as it can generate degradable microplastics (DMPs), especially when these DMPs coexist with heavy metals in soil. Taking petrochemical-based poly(butylene adipate-co-terephthalate) (PBAT) and bio-based polylactic acid (PLA) as representative DMPs, this study investigated how DMPs affect the adsorption–desorption behavior of Cu²⁺ in soil and the underlying mechanisms via batch equilibrium experiments and characterization analyses. The experiments revealed that ion exchange (accounting for 33.6–34.3%), oxygen-containing functional group complexation, and electrostatic interactions were the primary adsorption driving forces, with chemical adsorption playing the main role. Compared to the soil, the PBAT and PLA had smaller specific surface areas and pore volumes, fewer oxygen-containing functional groups, and especially lacked O-metal functional groups. They can dilute soil, clog its pores, and cover its active sites. 1% DMPs significantly reduced the soil’s equilibrium adsorption capacity (Q_e) (3.7–4.7%) and increased equilibrium desorption capacity (Q_De) (1.7–2.6%), thereby increasing the mobility and ecological risk of Cu²⁺. PBAT and PLA had no significant difference in effects on the adsorption, but their specific mechanisms were somewhat distinct. Faced with the prevalent, worsening coexistence of DMPs and heavy metals in soil, these findings contribute to the ecological risk assessment of DMPs. Full article

This study addresses the development of advanced anode materials for lithium-ion batteries by investigating the high-entropy perovskite La(Co_0.2Mn_0.2Fe_0.2Ni_0.2Cu_0.2)O₃. The material was synthesized via spray drying of aqueous metal nitrate solutions, followed by calcination at various temperatures (800 °C/1 h, 1000 °C/1 h, 1000 °C/2 h, 1100 °C/1 h) to optimize structural properties. Structural analysis using X-ray diffraction confirmed the formation of a single-phase perovskite in the sample calcined at 1100 °C for 1 h, while SEM/EDS revealed homogeneous elemental distribution. Electrochemical testing of the powders as anode materials in coin-type lithium-ion cells revealed a trend of slightly increasing capacity over 150 cycles, with capacity ultimately reaching 617 mAh g⁻¹, indicating progressive electrochemical activation. Although the samples share the same composition, variations in calcination conditions resulted in differences in capacity and cycling behavior. These results demonstrate that synthesis parameters critically influence the electrochemical performance of high-entropy perovskites. The findings suggest that such materials have potential as stable anodes for next-generation lithium-ion batteries, contributing to improved durability and efficiency in energy-storage technologies. Full article

The catalytic performance of metal oxide materials is profoundly influenced by both chemical composition and surface morphology, particularly at high dopant loadings where metallic clusters can form. Here, we use density functional theory (DFT) to elucidate how copper incorporation—either as isolated dopants or as surface clusters—modulates the mechanism and activity of ZrO₂ catalysts in the direct carboxylation of phenol to para-hydroxybenzoic acid. Our results reveal that while Cu doping inhibits C–H bond activation, the presence of Cu clusters at the ZrO₂ surface dramatically lowers the barrier for C–C coupling with CO₂, owing to unique interfacial sites that facilitate substrate activation and CO₂ bending. We show that the reaction mechanism shifts from an Eley–Rideal pathway on pure ZrO₂ to a Langmuir–Hinshelwood mechanism on Cu-modified surfaces, with the rate-determining step depending on the Cu morphology. These findings demonstrate that even small amounts of metallic clusters can fundamentally alter catalytic pathways, providing actionable insights for the rational design of heterogeneous catalysts for selective aromatic carboxylation. Full article

Electrocatalytic CO₂ reduction driven by renewable electricity offers a sustainable approach to producing valuable chemicals, though it is often hindered by low activity and selectivity. CuO, an important transition metal oxide, exhibits unique advantages in photoelectrocatalysis due to its high intrinsic catalytic activity and ability to serve as an active site for CO₂ reduction. SiO₂, a widely used substrate, facilitates Cu loading and increases the specific surface area of the catalyst. Meanwhile, g-C₃N₄ provides excellent visible-light responsiveness and efficient charge carrier mobility. Together, CuO, SiO₂, and g-C₃N₄ are earth-abundant, low-cost, and chemically stable, making them ideal for solar-to-fuel applications. Here, a novel ternary heterojunction photocatalyst was constructed using SiO₂, CuO, and g-C₃N₄. The heterostructure significantly improves light-harvesting efficiency, promotes efficient charge separation and transport, and simultaneously mitigates photogenerated carrier recombination and catalyst corrosion. The resulting SiO₂@CuO/g-C₃N₄ catalyst demonstrates outstanding CO₂ conversion performance, achieving a CO yield of 17 mmolg⁻¹h⁻¹ at 1.2 V_RHE with nearly 100% selectivity. Moreover, this work systematically investigates the electrocatalytic CO₂ reduction reaction (CO₂RR) mechanism on Cu-based catalysts, offering insights into the formation of high-value multicarbon products and highlighting the potential of rational heterojunction design in enhancing solar-driven fuel production efficiency. Full article