Search Results (178)

This study presents the development of Cu-doped NiMo/TiO₂ photoelectrocatalysts for simultaneous green hydrogen production and pharmaceutical pollutant removal under simulated solar irradiation. The catalysts were synthesized via wet impregnation (15 wt.% total metal loading with 0.6 wt.% Cu) and thermally treated at 400 °C and 900 °C to investigate structural transformations and catalytic performance. Comprehensive characterization (XRD, BET, SEM, XPS) revealed phase transitions, enhanced crystallinity, and redistribution of redox states upon Cu incorporation, particularly the formation of NiTiO₃ and an increase in oxygen vacancies. Crystallite sizes for anatase, rutile, and brookite ranged from 21 to 47 nm at NiMoCu400, while NiMoCu900 exhibited only the rutile phase with 55 nm crystallites. BET analysis showed a surface area of 44.4 m²·g⁻¹ for NiMoCu400, and electrochemical measurements confirmed its higher electrochemically active surface area (ECSA, 2.4 cm²), indicating enhanced surface accessibility. In contrast, NiMoCu900 exhibited a much lower BET surface area (1.4 m²·g⁻¹) and ECSA (1.4 cm²), consistent with its inferior photoelectrocatalytic performance. Compared to previously reported binary NiMo/TiO₂ systems, the ternary NiMoCu/TiO₂ catalysts demonstrated significantly improved hydrogen production activity and more efficient photoelectrochemical degradation of paracetamol. Specifically, NiMoCu400 showed an anodic peak current of 0.24 mA·cm⁻² for paracetamol oxidation, representing a 60% increase over NiMo400 and a cathodic current of –0.46 mA·cm⁻² at –0.1 V vs. RHE under illumination, nearly six times higher than the undoped counterpart (–0.08 mA·cm⁻²). Mott–Schottky analysis further revealed that NiMoCu400 retained n-type behavior, while NiMoCu900 exhibited an unusual inversion to p-type, likely due to Cu migration and rutile-phase-induced realignment of donor states. Despite its higher photosensitivity, NiMoCu900 showed negligible photocurrent, confirming that structural preservation and surface redox activity are critical for photoelectrochemical performance. This work provides mechanistic insight into Cu-mediated photoelectrocatalysis and identifies NiMoCu/TiO₂ as a promising bifunctional platform for integrated solar-driven water treatment and sustainable hydrogen production. Full article

Fluorinated organic molecules have become indispensable in modern chemistry, owing to the unique properties imparted by fluorine to other compounds, including enhanced metabolic stability, controlled lipophilicity, and improved bioavailability. The site-selective incorporation of fluorine atoms into organic frameworks is essential in pharmaceutical, agrochemical, and material science research. In recent years, catalytic fluorination has become an important methodology for the efficient and selective incorporation of fluorine atoms into complex molecular architectures. This review highlights advances in catalytic fluorination reactions over the past six years and describes the contributions of transition metal catalysts, photocatalysts, organocatalysts, and electrochemical systems that have enabled site-selective fluorination under a variety of conditions. Particular attention is given to the use of well-defined fluorinating agents, including Selectfluor, N-fluorobenzenesulfonimide (NFSI), AlkylFluor, Synfluor, and hypervalent iodine reagents. These reagents have been combined with diverse catalytic systems, such as AgNO₃, Rh(II), Mo-based complexes, Co(II)-salen, and various organocatalysts, including β,β-diaryl serine catalysts, isothiourea catalysts, and chiral phase-transfer catalysts. This review summarizes proposed mechanisms reported in the original studies and discusses examples of electrophilic, nucleophilic, radical, photoredox, and electrochemical fluorination pathways. Recent developments in stereoselective and more sustainable protocols are also examined. By consolidating these strategies, this article provides an up-to-date perspective on catalytic fluorination and its impact on synthetic organic chemistry. Full article

This work concerns the preparation of Pt/AC catalysts (Pt supported on activated carbon) and their application to the synthesis of hydrocarbon biofuels through the HEFA (hydroprocessing of esters and fatty acids) route. The key motivation for the work was that catalysts based on sulfided Mo supported on γ-Al₂O₃, traditionally employed in the hydroprocessing of petroleum derivatives, (i) are unstable in the HDO (hydrodeoxygenation) of biomass-derived feedstocks and (ii) can contaminate the resulting biofuels with sulfur. In this context, a systematic study on the effects of preparation conditions on the properties of the resulting Pt/AC catalysts and their performance in HEFA was carried out for the first time. Efficient catalysts were obtained, which led to the complete deoxygenation of lauric acid and coconut oil, yielding products composed primarily of n-alkanes. The highest HDO activity was verified for the catalyst prepared using as a support an AC previously subjected to thermal treatment up to 800 °C in a H₂ atmosphere (which removed most of the surface acidic oxygenated groups), depositing Pt over the surface of this support via wet impregnation using a H₂PtCl₆ solution acidified with HCl. The obtained results showed the great potential of the Pt/AC catalysts for the production of hydrocarbon biofuels through the HEFA route. Full article

MXenes have emerged as promising candidates for energy storage and catalyst design. Through detailed density functional theory (DFT) calculations, we designed a series of new 2D composite MXene-based nanomaterials by covering excellent TM₃N₂ MXenes (TM = Nb, Ta, Mo, and W) with graphene or buckled silicene. Our findings demonstrate that this coating can lead to high catalytic activity for hydrogen evolution reactions (HER) in these composite MXene-based systems, with silicene exhibiting superior performance compared to graphene. The relevant carbon and silicon atoms in the coated materials serve as active sites for HER due to complex electron transfer processes. Additionally, doping N or P atoms into graphene/silicene, which have similar atomic radii, but larger electronegativity than C/Si atoms, can further enhance the HER activity of adjacent carbon or silicon atoms, thus endowing the composite systems with higher HER catalytic performance. Coupled with their high stability and metallic conductivity, all these composite systems show great potential as electrocatalysts for HER. These remarkable findings offer new strategies and valuable insights for designing non-precious and highly efficient MXene-based HER electrocatalysts. Full article

Ru-based catalysts manifest unparalleled hydrogen evolution reaction (HER) performance, but the hydrolysis of Ru species and the accumulation of corresponding reaction intermediates greatly limit HER activity and stability. Herein, Ru nanoparticle assemblies modified with single Mo atoms and supported on N-incorporated graphene (referred to as MoRu-NG) are compounded via hydrothermal and chemical vapor deposition (CVD) methods. The incorporation of single Mo atoms into Ru lattices modifies the local atomic milieu around Ru centers, significantly improving HER catalytic behavior and stability. More specifically, MoRu-NG achieves overpotentials of 53 mV and 28 mV at 10 mA cm⁻², with exceptional stability in acidic and alkaline seawater solutions, respectively. In MoRu-NG, Ru atoms have a special electronic structure and thus possess optimal hydrogen adsorption energy, which indicates that excellent HER activity mainly hinges upon Ru centers. To be specific, the d-electron orbitals of Ru atoms are close to half full, giving Ru atoms moderate bond energy for the assimilation and release of hydrogen, which is beneficial for the conversion of reaction intermediates. Moreover, the incorporation of single Mo atoms facilitates the formation of O and O’-bidentate ligands, significantly enhancing the structural stability of MoRu-NG in universal-pH seawater electrolysis. This work advances a feasible construction method of hexagonal octahedral configuration (Ru-O-Mo-N-C) and provides a route to synthesize an efficient and stable catalyst for electrocatalytic HER in universal-pH seawater. Full article

Piezoelectric and photocatalytic technologies use mechanical and light energy to decompose environmental contaminants, demonstrating a beneficial synergistic impact. This investigation employs a two-step hydrothermal-calcination technique to synthesize N-doped MoS₂ photocatalytic materials. The ideal catalyst, N-MoS₂-3, utilizing the synergistic effect of piezoelectric–photocatalysis processes, attained a TC degradation rate of 90.8% in 60 min. The kinetic constant (0.0374 min⁻¹) is 1.75 times greater than the combined rates of single photocatalysis and piezoelectric catalysis, indicating a notable synergistic impact. The material has 80% degradation efficiency after five cycles, indicating its remarkable resilience. Mechanistic investigations reveal that nitrogen doping establishes an internal electric field by modulating the S-Mo-S charge distribution. Photogenerated electrons move to generate •O₂⁻, while holes accumulate internally. The ultrasound-induced piezoelectric polarization field interacts with the photogenerated electric field in reverse, thereby synergistically improving carrier separation efficiency and facilitating redox processes. This study emphasizes the viability of non-metal doping as a method for modifying the properties of two-dimensional materials, offering a novel approach to enhance the synergistic attributes of piezoelectric and photocatalytic processes. This technology possesses significant promise for environmental restoration through the utilization of solar and mechanical energy. Full article

Sulfur hexafluoride (SF₆), the strongest greenhouse gas, has great challenges in degradation because of its stable structure, posing significant environmental concerns. Photocatalysis offers an environmentally friendly, low-energy solution, but the fluoride deposition on catalysts reduces their activity, thus limiting their large-scale application. To prevent catalyst fluoride poisoning, we report a thin-layer graphitic carbon nitride (CN) material loaded with MoO_x (CNM) that resists fluoride deposition for long-term SF₆ degradation. By combining molecular structure design and nanostructure regulation, we construct a photocatalyst with enhanced charge carrier mobility and reduced transport distances. We find that the CNM exhibits a high specific surface area, increased contact between reactants and active sites, and efficient electron–hole separation due to the Mo-N bonds, achieving an SF₆ degradation efficiency of 1.73 mmol/g after one day due to the prolonged catalytic durability of the catalyst, which is eight times higher than pristine g-C₃N₄ (0.21 mmol/g). We demonstrate the potential of CNMs for low-energy, high-efficiency SF₆ degradation, offering a new approach to mitigate the environmental impact of this potent greenhouse gas. We envision that this study will inspire further research into advanced photocatalytic materials for environmental remediation, contributing to global efforts in combating climate change. Full article

The key to selectively cleaving C–O bonds in lignin to produce high-value aromatic chemicals lies in the development of efficient and stable catalysts. In this study, a heterostructured catalyst with N-doped carbon-supported Co and dual-phase Mo_xC nanoparticles was prepared via the in situ pyrolysis of a Co–Mo–N precursor. The dual-phase α-MoC/β-Mo₂C heterostructure is adjusted by varying the Co:Mo ratio to affect the structure and electronic properties of the catalyst. The heterostructures bring about enhanced electron transfer from Co to Mo, which promotes hydrogen dissociation over the Co sites, significantly improving the catalyst’s hydrogenolysis activity and stability. The optimal catalyst with Co₁Mo_xC@NC exhibits excellent hydrogenolysis activity; under the optimal reaction conditions (260 °C, 1 MPa H₂, 3 h), the yield of aromatic monomers reaches 28.5%. Such prominent performance not only benefits from the numerous α-MoC/β-Mo₂C hetero-interfaces that offer abundant active sites for hydrogen dissociation, but also should be ascribed to the strong synergistic effect between Co and Mo. Full article

Developing a catalyst with excellent electrical conductivity and catalytic performance for on-site testing of residual imidacloprid is significant and challenging. In situ growth of Mo₂C nanodots on Co-induced N-doped carbon nanotubes (Co/Mo₂C/N-CNT) was synthesized to construct a molecularly imprinted electrochemical sensor for the detection of imidacloprid. The results proved that the catalytic performance of Co/Mo₂C/N-CNT for imidacloprid was over two times higher than those of Co/N-CNT and commercial CNT. This improvement was attributed to the formation of a heterostructure between Co species, Mo₂C, and N-CNT, which facilitated highly exposed catalytic active sites. Additionally, the abundant Mo₂C nano-dots promoted interfacial charge transfer to achieve optimal dynamics. The optimum preparation parameters of the catalysts were obtained by response surface methodology. By analyzing the relationship between different pH values and peak potential, as well as the influence of different scanning rates on peak potential, it was deduced that the possible electrocatalytic mechanism of imidacloprid involved the reduction of the nitro group to a hydroxylamine group and H₂O. Under optimal conditions, the limit of detection (LOD) was 0.033 × 10⁻⁶ mol·L⁻¹ (R² = 0.99698), and the linear range was 0.1 × 10⁻⁶~100 × 10⁻⁶ mol·L⁻¹. The application effect of the prepared sensor was evaluated by measuring the imidacloprid in two kinds of tea, indicating that the sensor possessed good sensitivity and selectivity, and was capable of meeting the requirements of on-site detection. Full article

This study aimed to synthesize a multicationic hydrotalcite and transform it into mixed oxide nanostructures (ZnO/TiO₂/CeO₂/Al₂O₃, referred to as MixO) to serve as a heterogeneous photocatalyst for degrading various pollutants, including methylene blue (MB), methyl orange (MO), paracetamol (PA), and paraquat (PQ). The hydrotalcite was synthesized via an ultrasound-assisted method and calcined at 700 °C to obtain the corresponding mixed metal oxide. A comprehensive characterization of both the multicationic hydrotalcite (MC-LDH) and the mixed metal oxides (MixO) was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), N₂ adsorption–desorption, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and pH_PZC analysis. The MixO sample exhibited an optical bandgap of 3.19 eV. Photocatalytic performance was evaluated during 240 min of UV irradiation, demonstrating high degradation efficiencies attributable to the synergistic interactions among ZnO, TiO₂, and CeO₂. Degradation efficiencies reached 99.3% for MO and 95.2% for MB, while PA and PQ showed moderate degradation rates of 60% and 15%, respectively. The degradation kinetics of all pollutant compounds followed the Langmuir–Hinshelwood model. Additionally, the MixO catalyst maintained consistent performance over four consecutive degradation cycles, highlighting its reusability and stability. These findings underscore the potential of MixO mixed oxide nanostructures as practical and recyclable photocatalysts for environmental remediation, particularly in wastewater treatment applications. Full article

Non-noble metal electrocatalysts for the hydrogen oxidation reaction (HOR) that are both highly active and low-cost are essential for the widespread use of fuel cells. Herein, a simple two-step method for creating an in-plane heterostructure of Ni₃N/MoSe₂ loaded on N-doped reduced graphene oxide (Ni₃N/MoSe₂@N-rGO) as an effective electrocatalyst for the HOR is described. The process involves hydrothermal treatment of the Ni and Mo precursors with N-doped reduced graphene oxide, followed by the annealing with urea. The Ni₃N/MoSe₂@N-rGO catalyst exhibits high activities for the HOR, with current densities of 2.15 and 3.06 mA cm⁻² at 0.5 V vs. the reversible hydrogen electrode (RHE) in H₂-saturated 0.1 M KOH and 0.1 M HClO₄ electrolytes, respectively, which is comparable to a commercial 20% Pt/C catalyst under similar experimental conditions. Furthermore, the catalyst demonstrates excellent durability, maintaining its performance during accelerated degradation tests for 5000 cycles. This work offers a practical framework for the designing and preparing of non-precious metal electrocatalysts for the HOR in fuel cells. Full article

We successfully synthesize monodisperse sulfhydryl-modified mesoporous organosilica nanospheres (MONs-SH) via one-step hydrolytic condensation, where cetyltrimethylammonium chloride and dodecyl sulfobetaine are employed as dual-template agents with (3-mercaptopropyl)triethoxysilane and 1,2-bis(triethoxysilyl)ethane as the precursors and concentrated ammonia as the alkaline catalyst. The prepared MONs-SHs deliver a large specific surface area (729.15 m² g⁻¹), excellent monodispersity, and homogeneous particle size. The introduction of ethanol into the reaction systems could expand the particle size of the synthesized MONs-SH materials from 18 to 182 nm. Moreover, the successful modification of -SH groups endowed MONs-SHs with an excellent adsorption capacity (297.12 mg g⁻¹) for Pb²⁺ ions in aqueous solution through ion exchange and complexation function. In addition, the established isotherm model and kinetic analyses reveal that the adsorption of Pb²⁺ ions on MONs-SHs follows the secondary reaction kinetic models, where both physisorption and chemisorption contribute to the adsorption of Pb²⁺ ions. The favorable recyclability of MONs-SHs is demonstrated with the maintained adsorption efficiency of 85.35% after six cycles. The results suggest that the synthesized MONs-SHs exhibit considerable application prospects for effectively eliminating Pb²⁺ ions from aqueous solutions. Full article

An electrocatalytic nitrogen reduction reaction (eNRR) presents an appealing strategy for ammonia (NH₃) production at ambient conditions. Through systematic density functional theory (DFT) calculations, the eNRR performance of 23 double-atom catalysts has been investigated. These catalysts are composed of a Mo atom and a transition metal atom anchored on the graphdiyne (GDY), and they are named MoM-GDYs. Among the 23 MoM-GDYs studied, 14 MoM-GDYs highlighted catalytic selectivity by inhibiting a competitive hydrogen evolution reaction (HER) and demonstrated commendable eNRR catalytic performance. MoRu-GDY, MoMo-GDY, MoFe-GDY and MoY-GDY exhibited excellent eNRR catalytic activity with limiting potentials of −0.05 V, −0.13 V, −0.21 V and −0.24 V, respectively. These 14 catalysts favor N₂ adsorption compared to H and exhibit less negative U_L than the −0.98 V benchmark of the stepped Ru(0001) surface. Among them, MoRu-GDY has the best catalytic activity with an U_L of −0.05 V. The excellent catalytic performance originates from the synergistic effect of the dual catalytic sites, where the alternation of the consecutive and enzymatic paths effectively reduces the limiting potentials. In addition, the catalytic activity can be evaluated using ΔG*_NH3 − ΔG*_NH2 as a theoretical descriptor, while U_L and the ΔG*_NH3 − ΔG*_NH2 fit coefficient R² reached 0.99. These findings not only contribute to the development of dual-atom electrocatalysts for eNRR but also offer a valuable pathway for identifying new eNRR catalysts with high activity and selectivity. Full article

C4 and C5 fractions are significant by-products in the ethylene industry, with considerable research and economic potential when processed through hydrogenation technology to enhance their value. This study explored the development of hydrotreating catalysts using composite oxides as carriers, specifically enhancing low-temperature performance by incorporating electronic promoters and employing specialized surface modification techniques. This approach enabled the synthesis of non-noble metal hydrogenation catalysts supported on Al₂O₃–TiO₂ composite oxides. The catalysts were characterized using various techniques, including X-ray diffraction, N₂ adsorption-desorption, scanning electron microscopy, X-ray photoelectron spectroscopy, ammonia temperature-programmed desorption, infrared spectroscopy, and transmission electron microscopy. Mo–Ni/Al₂O₃–TiO₂ catalysts were optimized for low-temperature hydrotreating of C4 and C5 fractions, demonstrating stable performance at inlet temperatures far below those typically required. This finding enables a shift from traditional gas-phase to gas–liquid two-phase reactions, eliminating the need for high-pressure steam in industrial settings. As a result, energy consumption is reduced, and operational stability is significantly improved. Full article

The development of effective catalytic systems for deoxygenation reactions is critical to the conversion of renewable feedstocks into sustainable fuels. In this work, the influence of various reaction parameters on the conversion of palmitic acid into alkanes, such as temperature, stirring rate, reaction time, H₂ pressure, amount of catalyst and substrate concentration was evaluated using the commercial Co-Mo/Al₂O₃ catalyst. In parallel, bimetallic Co-Mo catalysts supported on carbon nanotubes (CNTs) were prepared and characterized using various techniques, and their catalytic performance was assessed under the optimized conditions. The results showed that palmitic acid can be efficiently converted at 350 °C for 6 h at 30 bar H₂ pressure, stirring at 150 rpm and using 0.25 g of catalyst and 0.50 g of palmitic acid in 50 mL of n-decane. Under these conditions, a complete substrate conversion and yields of 89.4 and 4.8% of C₁₆ and C₁₅ were achieved. In addition, Co-Mo/CNT_ox presented a similar catalytic performance as the commercial one, with a final result of 90.9% yield in C₁₆. These findings point out the potential of using Co-Mo/CNT_ox as a competitive alternative to liquid fuel production. Full article