Search Results (166)

The efficient simultaneous removal of NO_x and CO from sintering flue gas under low-temperature conditions (110–180 °C) in iron and steel enterprises remains a significant challenge in the field of environmental catalysis. In this study, we present an innovative strategy to enhance the performance of CuSmTi catalysts through silver modification, yielding a bifunctional system capable of oxygen structure regulation and demonstrating superior activity for the combined NH₃-SCR and CO oxidation reactions under low-temperature, oxygen-rich conditions. The modified AgCuSmTi catalyst achieves complete NO conversion at 150 °C, representing a 50 °C reduction compared to the unmodified CuSmTi catalyst (T_100% = 200 °C). Moreover, the catalyst exhibits over 90% N₂ selectivity across a broad temperature range of 150–300 °C, while achieving full CO oxidation at 175 °C. A series of characterization techniques, including XRD, Raman spectroscopy, N₂ adsorption, XPS, and O₂-TPD, were employed to elucidate the Ag-Cu interaction. These modifications effectively optimize the surface physical structure, modulate the distribution of acid sites, increase the proportion of Lewis acid sites, and enhance the activity of lattice oxygen species. As a result, they effectively promote the adsorption and activation of reactants, as well as electron transfer between active species, thereby significantly enhancing the low-temperature performance of the catalyst. Furthermore, in situ DRIFTS investigations reveal the reaction mechanisms involved in NH₃-SCR and CO oxidation over the Ag-modified CuSmTi catalyst. The NH₃-SCR process predominantly follows the L-H mechanism, with partial contribution from the E-R mechanism, whereas CO oxidation proceeds via the MvK mechanism. This work demonstrates that Ag modification is an effective approach for enhancing the low-temperature performance of CuSmTi-based catalysts, offering a promising technical solution for the simultaneous control of NO_x and CO emissions in industrial flue gases. Full article

The development of high-performance and stable solid-state lithium batteries (SSBs) is critical for advancing next-generation energy storage technologies. This study investigates LATP (Li_1.3Al_0.3Ti_1.7(PO₄)₃) coatings to enhance the electrochemical performance and interface stability of NCMA83 (LiNi_0.83Co_0.06Mn_0.06Al_0.05O₂) cathodes. Compared to conventional combinations with LPSC (Li₆PS₅Cl) solid electrolytes, LATP coatings significantly reduce interfacial reactivity and improve cycling stability. Structural and morphological analyses reveal that LATP coatings maintain the crystallinity of NCMA83 while fine-tuning its lattice stress. Electrochemical testing demonstrates that LATP-modified samples (83L5) achieve superior capacity retention (65 mAh/g after 50 cycles) and reduced impedance (R_ct ~200 Ω), compared to unmodified samples (83L0). These results highlight LATP’s potential as a surface engineering solution to mitigate degradation effects, enhance ionic conductivity, and extend the lifespan of high-capacity SSBs. Full article

The degradation of polypropylene (PP) through thermal and mechanical stress, as well as the influence of oxygen, are unavoidable when processing on a co-rotating twin-screw extruder. In previous studies, a mathematical model was developed to predict the degradation while compounding on different twin-screw extruder sizes. Additionally, the examination of filled PPs was conducted. To this end, a range of operating parameters and extruder sizes were used to process PP, and the molar mass was then determined by melt flow rate (MFR) and gel permeation chromatography (GPC) measurements to derive the degree of degradation. The model was then modified by adjusting the sensitivity parameters to allow the degradation behavior of the PPs to be described independently of extruder size. Consistent with prior research, comprehensive measurements of a PP/titanium dioxide (TiO₂) compound revealed that, with a few exceptions, increasing temperatures and screw speeds and decreasing throughputs generally resulted in higher degradation. However, the application of the model to the compounds did not achieve good agreement with the measured degradation, indicating different degradation conditions due to the different thermodynamic and rheological properties of the compounds. Full article

The present work examines pure and palladium photofixed TiO₂ and binary (TiO₂/ZnO) photocatalysts for breaking down tartrazine, a food coloring agent, in distilled water. Powders with the following compositions are obtained using the sol-gel process: 100TiO₂, 10TiO₂/90ZnO, 50TiO₂/50ZnO, and 90TiO₂/10ZnO. The composite materials are analyzed using SEM-EDS, UV-Vis, DTA-TG, and X-ray diffraction. The synthesized gels are then photo-fixed with UV light to incorporate palladium ions and are also examined for tartrazine (E102) degradation. The photocatalytic tests were carried out in a cylindrical glass reactor illuminated by ultraviolet light. Compared to mixed binary catalysts, the prepared pure TiO₂ catalyst demonstrated greater activity in the photodegradation of tartrazine (E102). The further of a specific quantity of zinc oxide reduced the catalytic properties of TiO₂. The recombination of photoinduced electron-hole pairs in ZnO may account for this. In comparison to the pure samples, the co-catalytic palladium-modified gels exhibited higher photocatalytic efficiency. Heterojunction and palladium modification of the composites partially captured and transferred the electrons. Consequently, the longer lifetime of the photogenerated charges improved the catalytic activity of the palladium titanium dioxide and binary gels. Additionally, under UV light, pure and palladium photofixed TiO₂ and binary sol-gel samples displayed excellent stability for tartrazine photodegradation. Full article

To address the issue of air pollution caused by automobile exhaust in China, a titanium dioxide/graphite carbon nitride (TiO₂/g-C₃N₄) composite photocatalyst capable of degrading automobile exhaust was prepared in this study. It was used as an additive to modify styrene–-butadiene latex (SBR) emulsified asphalt. The basic properties of modified emulsified asphalt before and after aging were analyzed, and the dosage range of TiO₂/g-C₃N₄ (TCN) was determined. The environmentally friendly micro-surfacing of degradable automobile exhaust was prepared. Based on 1 h and 6 d wet wheel wear test, rutting deformation test, surface structure depth test, and pendulum friction coefficient test, the road performance of TCN environmentally friendly micro-surfacing mixture with different contents was analyzed and evaluated, and the effect of environmentally friendly degradation of automobile exhaust was studied by a self-made degradation device. The results show that when the mass ratio of TiO₂ and melamine was 1:4, the TCN composite photocatalyst had strong photocatalytic activity. The crystal structure of TiO₂ and g-C₃N₄ was not damaged during the synthesis process. The g-C₃N₄ inhibited the agglomeration of TiO₂. The introduction of N-Ti bond changed the electronic structure of TiO₂, narrowed the band gap and broadened the visible light response range. When the TCN content was in the range of 1~7%, the softening point of SBR- modified emulsified asphalt increased with the increase in TCN content, the penetration decreased, the ductility decreased gradually, and the storage stability increased gradually. The penetration ratio and ductility ratio of the composite-modified emulsified asphalt after aging increased with the increase in TCN content, and the increment of the softening point decreased. This shows that the TCN content is beneficial to the high-temperature performance and anti-aging performance of SBR-modified emulsified asphalt, and has an adverse effect on low temperature performance and storage stability. The addition of TCN can improve the wear resistance and rutting resistance of the micro-surfacing mixture, and has no effect on the water damage resistance and skid resistance. The environment-friendly micro-surfacing asphalt mixture had a significant degradation effect on NO, CO, and HC. With the increase in TCN content, the degradation efficiency of the three gases was on the rise. When the content was 5%, the degradation rates of NO, CO, and HC were 37.16%, 25.72%, and 20.44%, respectively, which are 2.34 times, 2.47, times and 2.30 times that of the 1% content, and the degradation effect was significantly improved. Full article

Surface and interface engineering play a crucial role in enhancing the CO₂ methanation performance of heterogeneous catalysts. In this study, we present NiO-TiO₂ nanoparticles modified with oxygen vacancy-rich Fe₃O₄ clusters, significantly improving CO₂ methanation performance. The as-prepared catalyst (referred to as NiO@Fe₃O₄) achieves an impressive CH₄ selectivity of 91.2% and a methane production yield of 6400.50 μmol/g at 573 K, an approximately 83% increase compared to unmodified NiO nanoparticles (3154.2 μmol/g). The results of physical characterizations and gas chromatography confirm that the outstanding activity and selectivity of the NiO@Fe₃O₄ catalyst arise from the synergistic interaction between its surface-active sites. Notably, the high concentration of oxygen vacancies within Fe₃O₄ enhances CO₂ activation, while adjacent NiO sites efficiently promote H₂ dissociation. These findings provide valuable insights into the rational design of heterogeneous catalysts, highlighting the advantages of Fe₃O₄ as an efficient promoter over conventional metal oxides for catalytic applications. Additionally, we envision that the obtained results will help to design transition metal-based industry viable catalysts for a diverse range of applications. Full article

The development of state-of-the-art gas sensors based on metal oxide semiconductors (MOS) to monitor hazardous and greenhouse gas (e.g., methane, CH₄, and carbon dioxide, CO₂) has been significantly advanced. Moreover, the morphological and topographical structures of MOSs have significantly influenced the gas sensors by means of surface catalytic activities. This work examines the impact of morphological and topological networked assembly of zinc oxide (ZnO) nanostructures, including microparticles and nanoparticles (0D), nanowires and nanorods (1D), nanodisks (2D), and hierarchical networks of tetrapods (3D). Gas sensors consisting of vertically aligned ZnO nanorods (ZnO–NR) and topologically interconnected tetrapods (T–ZnO) of varying diameter and arm thickness synthesized using aqueous phase deposition and flame transport method on interdigitated Pt electrodes are evaluated for methane detection. Smaller-diameter nanorods and tetrapod arms (nanowire-like), having higher surface-to-volume ratios with reasonable porosity, exhibit improved sensing behavior. Interestingly, when the nanorods’ diameter and interconnected tetrapod arm thickness were comparable to the width of the depletion layer, a significant increase in sensitivity (from 2 to 30) and reduction in response/recovery time (from 58 s to 5.9 s) resulted, ascribed to rapid desorption of analyte species. Additionally, nanoparticles surface-catalyzed with Pd (~50 nm) accelerated gas sensing and lowered operating temperature (from 200 °C to 50 °C) when combined with UV photoactivation. We modeled the experimental findings using a modified general formula for ZnO methane sensors derived from the catalytic chemical reaction between methane molecules and oxygen ions and considered the structural surface-to-volume ratios (S/V) and electronic depletion region width (L_d) applicable to other gas sensors (e.g., SnO₂, TiO₂, MoO₃, and WO₃). Finally, the effects of UV light excitation reducing detection temperature help to break through the bottleneck of ZnO-based materials as energy-saving chemiresistors and promote applications relevant to environmental and industrial harmful gas detection. Full article

Ammonia is one of the common inorganic pollutants in surface waters. It can come from a wide range of sources through the discharge of wastewater (industry, agriculture, and municipal waters). Catalytic ozonation reaction can efficiently remove ammonia nitrogen without introducing other pollutants and improve the nitrogen selectivity of reaction products by controlling the reaction conditions. Catalysts based on silver nanoparticles (Ag NPs) have shown excellent O₃ decomposition performance; therefore, they are promising catalysts for catalytic ammonia ozonation due to their high reactivity, stability, and selectivity to N₂. In this study, we synthesized well-defined silver nanoparticles (Ag NPs) using a modified alkaline polyol method and then dispersed them on solid oxide supports (Fe₃O₄, TiO₂, and WO₃). Before being deposited on the oxide support, the silver nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-VIS spectroscopy. The obtained catalysts, Ag_Fe₃O₄, Ag_TiO₂, and Ag_WO₃ were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area analysis, UV-VIS spectroscopy, temperature-programmed reduction (H₂-TPR), and temperature-programmed desorption (TPD) of CO₂ and NH₃. It has been demonstrated that the nature of the support significantly influences the physicochemical properties of the catalysts, as well as their catalytic performance in ammonia ozonation reaction. Full article

The increasing concentration of antibiotics in natural water poses a significant threat to society’s sustainable development due to water pollution. Photocatalytic technology is an efficient and environmentally friendly approach to environmental purification, offering great potential for addressing pollution and attracting significant attention from scholars worldwide. TiO₂, as a representative semiconductor photocatalytic material, exhibits strong oxidation ability and excellent biocompatibility. However, its wide band gap and the rapid recombination of photo-generated electron–hole pairs significantly limit its photocatalytic applications. Recent studies indicate that constructing heterojunctions with synergistic plasmonic effects is an effective strategy for developing high-performance photocatalysts. In this study, Bi metal nanoparticles and (BiO)₂CO₃ nanosheets were simultaneously grown on TiO₂ nanofibers via an in situ hydrothermal method, successfully forming a Bi@(BiO)₂CO₃/TiO₂ composite fiber photocatalyst with synergistic plasmonic effects. The surface plasmon resonance (SPR) effect of Bi nanoparticles combined with the (BiO)₂CO₃/TiO₂ heterojunction enhances sunlight absorption, facilitates efficient separation of photo-generated carriers, and significantly strengthens the photo-oxidation and reduction abilities. This system effectively generates abundant hydroxyl (·OH) and superoxide (·O²⁻) radicals under sunlight excitation. Consequently, Bi@(BiO)₂CO₃/TiO₂ exhibited outstanding photocatalytic performance. Under simulated sunlight for 60 min, the photodegradation efficiencies of the quinolone antibiotics lomefloxacin, ciprofloxacin, and norfloxacin reached 93.2%, 97.5%, and 100%, respectively. Bi@(BiO)₂CO₃/TiO₂ also demonstrates excellent stability and reusability. This study represents a significant step toward the application of TiO₂-based photocatalyst materials in environmental purification. Full article

Potassium hexatitanate whiskers are prepared and characterized in this study. The reinforcement of polyethylene with potassium hexatitanate whiskers is also investigated. The potassium hexatitanate whiskers are prepared through the calcination of TiO₂ and K₂CO₃ at 1000 °C. It is determined that a polyvinylpyrrolidone additive is crucial for the formation of slender rod-like structures with smooth and flat surfaces and a high length-to-diameter ratio. For the surface modification of the whiskers, γ-aminopropyl triethoxysilane has been identified as the most effective coupling agent for enhancing mechanical properties. The whiskers have little change in shape after surface modification, and the majority of the whiskers still retain a considerable length-to-diameter ratio. The results of mechanical tests indicate that the tensile strength and the modulus of elasticity, as well as the shear strength and the shear elasticity, are enhanced to some extent. The tensile strength and the modulus of elasticity increase by 18.6% and 3.6%, respectively. The modified polyethylene composites show enhanced softness and elasticity. The elongation at the break for the prepared PE/PHT-2-1 composites increases significantly to 38.1%, significantly exceeding that of unfilled polyethylene (6.84%). Nevertheless, a suitable method is established for reinforcing thermoplastic polymers using inexpensive potassium hexatitanate whiskers. Full article

CO selective methanation is regarded as an efficient technological solution for hydrogen-rich gas purification in fuel cells. In this study, a series of bimetallic catalysts (Ru-Ni/xTiO₂-MgAl₂O₄) were synthesized by impregnation method after surface modification of MgAl₂O₄ supports with different contents of TiO₂. The prepared catalysts were characterized by XRD, BET, SEM, TEM, H₂-TPR, CO-TPD, NH₃-TPD, and XPS. The Ru-Ni/10TiO₂-MgAl₂O₄ exhibited excellent CO-SMET performance, removing the CO in the H₂-rich gas to less than 10 ppm with the selectivity above 50% in a temperature window range of 210–280 °C. The results showed that the TiO₂-modified MgAl₂O₄ support not only improved the interaction between metal and support, and promoted the dispersion of active component nanoparticles on the support, but also introduced oxygen vacancies or defects in the catalyst and enhanced the acidity, resulting in better catalytic activity and stability. Full article

Metal–organic framework (MOF)-derived transition metal compounds and their composites have attracted great interest for applications in energy conversion and storage. In this work, hexagonal micro-prisms of Ni-doped CoTiO₃ composited with amorphous carbon (Ni_xCTO/C) were synthesized using Ti-Co-based MOFs as precursors. The experimental results indicate the substitutional doping of Ni²⁺ for Co²⁺ in CoTiO₃ (CTO), leading to improved conductivity, as further confirmed by density functional theory calculations. Thus, the carbon-free sample of Ni-doped CTO exhibits improved lithium storage properties compared to the pristine one. Furthermore, when coupled with in situ-formed carbon, the dually modified Ni_0.05CTO/C micro-prisms demonstrated a significantly increased reversible capacity of 584.8 mA h g⁻¹, excellent rate capability, and superior cycling stability at a high current density of 500 mA g⁻¹. This enhanced electrochemical performance can be attributed to the synergistic effect of Ni doping and carbon coating. Full article

This study explores the development and performance of photocatalytic cementitious composites modified with nano-TiO₂ to address urban air quality and sustainability challenges. Nine mortar series were prepared, incorporating binders with varying carbon footprints and mass contents across different series. The interplay between the fundamental (abrasion resistance) and functional (air purification efficiency) properties of the composites’ surfaces and interfaces was investigated. The photocatalytic removal of airborne pollutants, specifically nitrogen oxides (NOx) and ozone (O₃), was evaluated under simulated environmental conditions. The variations in binder composition influenced the composites’ overall initial carbon footprint and air purification efficiency. The assessment revealed a possible net decrease in carbon emissions over the life cycle of the composite due to the removal of ozone (greenhouse gas) and its precursor—NOx, highlighting the potential of photocatalytic cementitious composites for dual environmental benefits in an urban environment, emphasizing the critical role of surface and interface engineering in achieving carbon-negative composites. Full article

Polydispersed Ag species-modified TiO₂ samples with abundant oxygen vacancies were successfully prepared through the calcination of atomically precise Ag₃₃ nanocluster-loaded TiO₂ at an optimal temperature under a nitrogen atmosphere. The ligands of the Ag₃₃ nanoclusters are removed by extracting lattice oxygen from TiO₂ during the calcination, leading to the formation of CO₂, SO₂, and H₂O vapor. This process simultaneously induces Ag species sintering on the surface of TiO₂. The resulting nanocomposites exhibited excellent catalytic activity for the reduction of nitroarenes with NaBH₄ as the reductant. This is attributed to the produced Ag species on the oxygen-deficient TiO₂, which act as active centers for the catalytic process. Full article

To enhance the corrosion resistance of underground pipelines made of low carbon steel, nano-TiO₂-modified polyurea was applied to their surface. The anti-corrosion performance of these nano-TiO₂-modified coatings was tested by immersing them in a NACE (5 wt.% NaCl + 0.5 wt.% CH3COOH) solution under high temperatures and high CO₂ pressures. The mass variation, SEM morphology, and open-circuit potential were determined. EIS tests, neutral salt spray tests, and contact angle measurements were carried out to analyze the effect of nanoparticles on corrosion resistance. Within the same pressure range, the polyurea coating shows the highest corrosion resistance when 5% TiO₂ nanoparticles were added compared to that of polyurea coatings with 0%, 10%, and 15% TiO₂ added. Coatings with 5% TiO₂ nanoparticles showed rapid diffusion after being immersed for 96 h, indicating that the anti-corrosion performance of the coating weakened. Full article