Search Results (251)

Copper-doped indium zinc sulfides were synthesized by heating and stirring a mixture of zinc chloride, indium chloride tetrahydrate, thioacetamide, and copper chloride at 180 °C for 18 h. Among these, Zn_5.7Cu_0.3In₂S₉ exhibited a hydrogen-producing activity of 1660 μmol/g·h, which was approximately five times higher than that of pristine indium zinc sulfide. Therefore, the catalyst was characterized to investigate the effect of Cu addition. PL results revealed that the incorporation of Cu reduced the fluorescence intensity, indicating suppressed recombination of photogenerated electron–hole pairs. DRS showed that the Cu addition enhanced optical absorption in the visible-light region and narrowed the band gap. These findings suggest that the incorporation of copper into indium zinc sulfide improves its photocatalytic activity. Full article

The electrocatalytic decomposition of ammonia represents a promising route for sustainable hydrogen production, yet current systems rely heavily on noble metal catalysts with prohibitive costs and limited durability. A critical challenge lies in developing non-noble electrocatalysts that simultaneously achieve high active site exposure, optimized electronic configurations, and robust structural stability. Addressing these requirements, this study strategically engineered Cu-doped ZIF-8 architectures via in situ growth on nickel foam (NF) substrates through a facile room-temperature hydrothermal synthesis approach. Systematic optimization of the Cu/Zn molar ratio revealed that Cu_0.7Zn_0.3-ZIF/NF achieved optimal performance, exhibiting a distinctive nanoflower-like architecture that substantially increased accessible active sites. The hybrid catalyst demonstrated superior electrocatalytic performance with a current density of 124 mA cm⁻² at 1.6 V vs. RHE and a notably low Tafel slope of 30.94 mV dec⁻¹, outperforming both Zn-ZIF/NF (39.45 mV dec⁻¹) and Cu-ZIF/NF (31.39 mV dec⁻¹). Combined XPS and EDS analyses unveiled a synergistic electronic structure modulation between Zn and Cu, which facilitated charge transfer and enhanced catalytic efficiency. A gas chromatography product analysis identified H₂ and N₂ as the primary gaseous products, confirming the predominant occurrence of the ammonia oxidation reaction (AOR). This study not only presents a noble metal-free electrocatalyst with exceptional efficiency and durability for ammonia decomposition but also demonstrates the significant potential of MOF-derived materials in sustainable hydrogen production technologies. Full article

Photothermal catalytic CO₂ conversion into chemicals that provide added value represents a promising strategy for sustainable energy utilization, yet the development of highly efficient, stable, and selective catalysts remains a significant challenge. Herein, we report a rationally designed p-n junction heterostructure, T-CZ-PBA (SC), synthesized via controlled pyrolysis of high crystalline Prussian blue analogues (PBA) precursor, which integrates CuCo alloy, ZnO, N-doped carbon (NC), and Zn^II-Co^IIIPBA into a synergistic architecture. This unique configuration offers dual functional advantages: (1) the abundant heterointerfaces provide highly active sites for enhanced CO₂ and H₂ adsorption/activation, and (2) the engineered energy band structure optimizes charge separation and transport efficiency. The optimized T-C₃Z₁-PBA (SC) achieves exceptional photothermal catalytic performance, demonstrating a CO₂ conversion rate of 126.0 mmol gcat⁻¹ h⁻¹ with 98.8% CO selectivity under 350 °C light irradiation, while maintaining robust stability over 50 h of continuous operation. In situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) investigations have identified COOH* as a critical reaction intermediate and elucidated that photoexcitation accelerates charge carrier dynamics, thereby substantially promoting the conversion of key intermediates (CO₂* and CO*) and overall reaction kinetics. This research provides insights for engineering high-performance heterostructured catalysts by controlling interfacial and electronic structures. Full article

Organic soil pollution poses a persistent threat to environmental sustainability by disrupting nutrient cycling and ecosystem functioning. The biochar-activated persulfate (PS)-based advanced oxidation process (AOP) has emerged as a promising strategy for the sustainable remediation of organic-contaminated soils. This review provides a comprehensive overview of the recent progress in the PS-based degradation of organic pollutants, with a particular focus on the role of biochar as an efficient and environmental activator. This review further summarizes advancements in the design of modified biochars, including metal (Fe, Cu, Co, Mn, Zn, and La), non-metal (N, S, B, P), and functional group modifications, aimed at enhancing the PS activation efficiency while minimizing secondary environmental risks. Importantly, the overlooked contributions of soil microorganisms in PS/biochar systems are discussed, highlighting their potential to complement chemical oxidation and contribute to eco-compatible remediation pathways. This review emphasizes the sustainability-oriented evolution of PS/biochar technology, highlighting the importance of a cost-efficient implementation, ecological compatibility, and the rational engineering of smart, regenerable catalysts. These insights support the advancement of PS/biochar-based AOPs toward scalable, intelligent, and environmentally sustainable soil remediation. Full article

Leachates generated from the degradation of green waste and biosolids from urban wastewater treatment plants (WWTPs) pose significant environmental concerns due to high concentrations of organic pollutants and heavy metals. This study proposes a hybrid treatment strategy combining electrocoagulation (EC) and UVC-activated TiO₂ photocatalysis to remediate leachates produced in laboratory-scale biocells. Initial characterization revealed critical pollutant levels: COD (1373 mg/L), BOD₅ (378 mg/L), total phosphorus (90 mg/L), ammoniacal nitrogen (201 mg/L), and metals such as Ni, Pb, and Mn levels all exceeding those set out in the Ecuadorian discharge regulations. Optimized EC achieved removal efficiencies of 62.6% for COD, 44.4% for BOD₅, 89.8% for phosphorus, and 86.2% for color. However, residual contamination necessitated a subsequent photocatalytic step. Suspended TiO₂ under UVC irradiation removed up to 81.8% of the remaining COD, 88.7% of the ammoniacal nitrogen, and 94.4% of the phosphorus. Levels of heavy metals such as Zn, Fe, Pb, Mn, and Cu were reduced by over 80%, while Cr⁶⁺ was nearly eliminated. SEM–EDS analysis confirmed successful TiO₂ immobilization on sand substrates, revealing a rough, porous morphology conducive to catalyst adhesion; however, heterogeneous titanium distribution suggests the need for improved coating uniformity. These findings confirm the potential of the EC–TiO₂/UVC hybrid system as an effective and scalable approach for treating complex biocell leachates with reduced chemical consumption. Full article

5-aminotetrazole (5AT)-based gas generators, particularly the 5AT/NaIO₄ system, have garnered interest for their high gas production and energy potential. This study investigates the impact of various metal oxides (MnO₂, Al₂O₃, TiO₂, CuO, Fe₂O₃, MgO, ZnO, and MoO₃) on the thermal decomposition and combustion performance of 5AT/NaIO₄. The REAL calculation program was used to infer reaction products, which indicated that the gas products are almost all harmless, with negligibly low percentages of NO and CO. Thermogravimetric analysis revealed that metal oxides, especially MoO₃, significantly advance the decomposition process above 400 °C, reducing the activation energy by 130 kJ/mol and lowering critical ignition and thermal explosion temperatures. Combustion performance tests and closed bomb tests confirmed MoO₃’s positive effect, accelerating reaction rates and enhancing decomposition efficiency. The system’s high Gibbs free energy indicates non-spontaneous reactions. These findings provide valuable insights for designing environmentally friendly gas generators, highlighting MoO₃’s potential as an effective catalyst. Full article

Global municipal solid waste (~2B tons/year) affects sustainability, as landfill and incineration face persistent leachate contamination, demanding effective management to advance water recycling and circular economies. Accelerated investigation of hybrid biocatalytic ozonation systems is imperative to enhance contaminant removal efficiency for stringent discharge compliance. This study investigates the catalytic ozonation effects of γ-Al₂O₃-based catalysts loaded with different metals (Cu, Mn, Zn, Y, Ce, Fe, Mg) on the biochemical effluent of landfill leachate. The catalysts were synthesized via a mixed method and subsequently characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Pseudo-second-order kinetics revealed active metal loading’s impact on adsorption capacity, with Cu/γ-Al₂O₃ and Mg/γ-Al₂O₃ achieving the highest Q_e (0.85). To elucidate differential degradation performance among the catalysts, the ozone/oxygen gas mixture was introduced at a controlled flow rate. Experimental results demonstrate that the Cu/γ-Al₂O₃ catalyst, exhibiting optimal comprehensive degradation performance, achieved COD and TOC removal efficiencies of 84.5% and 70.9%, respectively. UV–vis absorbance ratios revealed the following catalytic disparities: Mg/γ-Al₂O₃ achieved the highest aromatic compound removal efficiency; Ce/γ-Al₂O₃ excelled in macromolecular organics degradation. EEM-PARAFAC analysis revealed differential fluorophore removal: Cu/γ-Al₂O₃ exhibited broad efficacy across all five components, while Mg/γ-Al₂O₃ demonstrated optimal removal of C2 and C4, but showed limited efficacy toward C5. These findings provide important insights into selecting catalysts in practical engineering applications for landfill leachate treatment. This study aims to elucidate catalyst formulation-dependent degradation disparities, guiding water quality-specific catalyst selection to ultimately enhance catalytic ozonation efficiency. Full article

CO₂ electrochemical reduction is a promising way to convert CO₂ to valuable fuels and chemicals. This study presents a porous Cu@Zn foam catalyst with a tailored hydrophobic surface for enhanced CO₂ reduction. The catalyst is synthesized via a modified dynamic hydrogen bubble template method, incorporating polytetrafluoroethylene (PTFE) during electrodeposition to control wettability. This strategy creates a hydrophobic microenvironment that significantly increases the three-phase (gas–liquid–solid) contact area, promoting CO₂ mass transfer and suppressing the competing hydrogen evolution reaction. The optimized Cu@Zn-8PTFE catalyst achieves a CO Faraday efficiency (FE_CO) of 87.53% at −35 mA cm⁻², a 40% improvement over the unmodified Cu@Zn. Furthermore, it also exhibits excellent stability, maintaining FE_CO > 90% for 64 h at −15 mA cm⁻². While hydrophobic modification is beneficial, excess PTFE loading reduces performance by covering active sites and diminishing the three-phase interface. This work highlights the importance of controlling catalyst wettability to optimize the three-phase interface for enhanced CO₂ electroreduction. Full article

The hydrogenation of CO₂ to methanol is an effective approach for utilizing carbon resources. Cu-ZnO-based catalysts have attracted significant attention due to their ability to activate CO₂; however, improving methanol selectivity remains a challenge. In this study, the incorporation of an appropriate amount of Ga into Cu-ZnO catalysts, resulting in the formation of spinel ZnGa₂O₄ crystals, significantly enhances the conversion of CO₂ to methanol. Ternary CuZnGa composite oxides with varying Ga contents were synthesized, and their effects on CO₂ hydrogenation were investigated. The optimal Cu₆Zn₃Ga₁ catalyst achieved a CO₂ conversion rate of 13% and a methanol selectivity of 59% under reaction conditions of 240 °C, 4 MPa, and a GHSV of 7500 mL⋅g_cat⁻¹⋅h⁻¹. In contrast, the undoped Cu₆Zn₄ catalyst exhibited a lower CO₂ conversion of 9.8% and a methanol selectivity of 38%. Characterization results indicate that the introduction of Ga promotes the formation of oxygen vacancies, enhances CO₂ activation, and facilitates electronic interactions between spinel ZnGa₂O₄ and Cu sites, thereby improving methanol production. Furthermore, the spinel ZnGa₂O₄-modified Cu catalyst demonstrated excellent stability over 90 h of continuous operation. This study presents a novel approach to designing spinel ZnGa₂O₄-modified Cu-ZnO-based catalysts and offers a new strategy for enhancing CO₂ hydrogenation to methanol. Full article

This research aimed to enhance biodiesel stability through catalytic transfer hydrogenation using a biomimetic bimetallic catalyst and glycerol as a hydrogen donor. The effects of catalyst species, intermediate solvent, glycerol feed, and glycerol form on biodiesel stability were investigated. In this study, the examined bimetallic catalysts were Zn-Cr-bicarbonate, Zn-Cr-formate, Zn-Cr-Ni, and Cu-Ni/SiO₂. Based on the results, the most excellent catalyst was presented by Cu-Ni/SiO₂ catalyst with DMF solvent and 10 wt% glycerol feed. This combination demonstrated a significant reduction in iodine (ΔIV = −4.9 g-I₂/100 g) and peroxide values (ΔPV = −5.2 meq-O₂/kg) accompanied by an elevation of oxidative stability (ΔOS = 4.3 h). Moreover, the reaction of catalytic transfer hydrogenation using these bimetallic catalysts followed the theoretical mechanism of the simultaneous dehydrogenation–hydrogenation process with two different metals. The promotion of bicarbonate and formate ions on the bimetallic catalyst provided hydrogen transfer assistance in the catalyst. Hence, the continuous improvement of biodiesel properties is expected to promote sustainable implementation of cleaner diesel fuel. Full article

This paper deals with synthesizing Zn, Cu, and AgNPs supported on the surface of zeolite Y for catalytic and antimicrobial applications. Firstly, the zeolite Na-Y was exchanged with solutions containing metal precursors and then a chemical treatment was used to transform the metal cations into metal nanoparticles. The different samples were characterized by different characterization methods. The reduction of methylene blue (MB) and orange (OG) dyes in the presence of NaBH₄ and nanocatalysts in a simple and binary system showed good results. It was shown in this study that the concentration of the reagents, the nature of metal species, and the nature of the dye can influence the conversion of the dye. The calculated kapp obtained by the best catalyst (Ag/Y) in a simple system was 1.882 min⁻¹ and 1.115 min⁻¹ for MB and OG dyes, respectively. It was found that the Ag/Y catalyst was more selective via MB in the binary system containing OG+MB dyes. The reuse of the Ag/Y catalyst in five cycles showed good results via the conversion of the MB dye without losing its performance. For antimicrobial activities, encouraging results have been recorded on different strains having inhibition zones between 14 and 25 mm. Full article

The reasonable design of low-cost, high-activity single-atom catalysts (SACs) is crucial for achieving highly efficient electrochemical CO₂RR. In this study, we systematically explore, using density functional theory (DFT), the performance of transition metal (TM = Mn, Fe, Co, Ni, Cu, Zn)-doped defect-type hexagonal boron nitride (h-BN) SACs TM@B₋₁N (B vacancy) and TM@BN₋₁ (N vacancy) in both CO₂RR and the hydrogen evolution reaction (HER). Integrated crystal orbital Hamiltonian population (ICOHP) analysis reveals that these catalysts weaken the sp orbital hybridization of CO₂, which promotes the formation of radical-state intermediates and significantly reduces the energy barrier for the hydrogenation reaction. Therefore, these theoretical calculations indicate that the Mn, Fe, Co@B₋₁N, and Co@BN₋₁ systems demonstrate excellent CO₂ chemical adsorption properties. In the CO₂RR pathway, Mn@B₋₁N exhibits the lowest limiting potential (U_L = −0.524 V), and its higher d-band center (−0.334 eV), which aligns optimally with the adsorbate orbitals, highlights its excellent catalytic activity. Notably, Co@BN₋₁ exhibits the highest activity in HER, while U_L is −0.217 V. Furthermore, comparative analysis reveals that Mn@B₋₁N shows 16.4 times higher selectivity for CO₂RR than for HER. This study provides a theoretical framework for designing bifunctional SACs with selective reaction pathways. Mn@B₋₁N shows considerable potential for selective CO₂ conversion, while Co@BN₋₁ demonstrates promising prospects for efficient hydrogen production. Full article

Under mild conditions, the effective conversion of carbon dioxide (CO₂) into formic acid (HCOOH) and carbon monoxide (CO) represents a promising avenue for mitigating greenhouse gas emissions and addressing energy crises. In this work, we analyzed the electro-catalytic activities of six metals (Ti, Fe, Ni, Cu, Zn, and Cr) anchored on monolayer molybdenum telluride (TM@MoTe₂) for the CO₂ reduction reaction (CO₂RR) from CO₂ to HCOOH and CO. Compared to the reversible hydrogen electrode, the limiting potential for HCOOH production on Ni@MoTe₂ is only about −0.38 V, and it is only about −0.20 V for the CO production on Cu@MoTe₂. The limiting potential is concerned with the free energies of *OCHO and *COOH. Both the CO₂RRs suppress the competing hydrogen evolution reaction (HER) and exhibit good selectivity for the desired reaction products. These features enable the efficient conversion of CO₂ into HCOOH on Ni@MoTe₂ or CO on Cu@MoTe₂. Our calculations could provide valuable insights for the design and synthesis of high-performance catalysts based on MoTe₂. Full article

This study focuses on optimizing the Reverse Water Gas Shift (RWGS) reaction system using a membrane reactor to improve CO₂ conversion efficiency. A one-dimensional simulation model was developed using FlexPDE Professional Version 8.01/W64 software to analyze the performance of ZSM-5 membranes integrated with 0.5 wt% Ru-Cu/ZnO/Al₂O₃ catalysts. The results show that the membrane reactor significantly outperforms the conventional Packed Bed Reactor by achieving higher CO₂ conversion (0.61 vs. 0.99 with optimized parameters), especially at lower temperatures, due to its ability to remove H₂O and shift the reaction equilibrium selectively. Key operational parameters, including temperature, pressure, and sweep gas flow rate, were optimized to maximize membrane reactor performance. The ZSM-5 membrane showed strong H₂O selectivity, with an optimum operating temperature of around 400–600 °C. The problem is that many reactants permeate at higher temperatures. Subsequently, a Half-MPBR design was introduced. This design was able to overcome the reactant permeation problem and increase the conversion. The conversion ratios for PBR, MPBR, and Half-MPBR are 0.71, 0.75, and 0.86, respectively. This work highlights the potential of membrane reactors to overcome the thermodynamic limitations of RWGS reactions and provides valuable insights to advance Carbon Capture and Utilization technologies. Full article

The thermocatalytic hydrogenation of CO₂ to methanol offers a promising route for reducing greenhouse gas emissions (GHG) and producing valuable chemicals and fuels. In this study, copper–zinc bimetallic catalysts supported on a zirconium-based MOF-808 framework were synthesized via a facile deposition–precipitation method and compared to a conventional Cu/ZnO/Al₂O₃ (CZA) catalyst. MOF-808 was selected due to its high surface area and porous structure, which enhance metal dispersion. Characterization through X-ray diffraction (XRD) and N₂ physisorption showed significant changes in surface area and pore structure after Cu-Zn incorporation and calcination. The 50-CuZn MOF-808 catalyst achieved the best catalytic performance at 260 °C and 40 bar, demonstrating a high STY of 193.32 gMeOH·Kgcat⁻¹ h⁻¹ and a turnover frequency (TOF) of 47.44 h⁻¹, surpassing traditional CZA catalysts. The strong Cu-Zn-Zr interactions within the MOF-808 framework played a crucial role in promoting CO₂ activation and methanol formation. This study underscores the potential of MOF-808-supported Cu-Zn catalysts as viable alternatives to traditional systems for CO₂ hydrogenation to methanol. Full article