Search Results (42)

The effects of Ce incorporation into trimetallic PtSnIn-supported catalysts were investigated for a propane dehydrogenation reaction with advanced characterization techniques. It was found that some Ce species exist in the form of CeAlO₃ on the reduced PtSnIn/xCe-Al catalyst, significantly enhancing the thermal stability of the alumina support. The NH₃-TPD measurements verified that the total acidity of the PtSnIn/xCe-Al catalysts decreases with the addition of Ce. The PtSnIn/1.5Ce-Al catalyst exhibits the optimal particle distribution with the smallest Pt particle size of 8.0 nm, which was revealed by TEM. The H₂-TPR and XPS results suggest that more oxidized-state Sn species form on catalyst surfaces, and the metal–support interaction can be strengthened when Ce is introduced. Furthermore, TG analysis demonstrates that Ce incorporation substantially reduces coke formation on the spent catalysts. The PtSnIn/1.5Ce-Al catalyst exhibits exceptional catalytic performance, achieving an initial propane conversion of 62.6% and maintaining a conversion of 57.2% after a 120 min reaction. In addition, the PtSnIn/1.5Ce-Al catalyst possesses high long-term stability. Over 40.0% propane conversion can be maintained after a 53 h continuous PDH reaction. These findings highlight the pivotal role of Ce in improving the structural properties and catalytic performance of PtSnIn-based catalysts for propane dehydrogenation, offering valuable insights for the design of highly efficient and stable dehydrogenation catalysts. Full article

The electrocatalytic hydrogenation (ECH) of biomass-derived phenolic compounds is a promising approach to the production of value-added chemicals and biofuels in a sustainable way under moderate reaction conditions. This study provides a comprehensive comparison of electrochemical and thermochemical hydrogenation processes, highlighting their relative advantages in terms of energy efficiency, product selectivity, and environmental impact. Several electrocatalysts (Pt, Pd, Rh, Ru), membranes (Nafion, Fumasep, GO-based PEMs), and reactor configurations are tested for the selective conversion of model compounds such as phenol, guaiacol, furfural, and levulinic acid. The contributions made by the electrode material, electrolyte composition, membrane nature, and reaction conditions are critically evaluated in relation to Faradaic efficiency, conversion rates, and product selectivity. The enhancement in the performance achieved by a new catalyst architecture is emphasized, such as MOF-based systems and bimetallic/trimetallic catalysts. In addition, a demonstration of graphite-based membranes and membrane-separated slurry reactors (SSERs) is provided, for enhanced ion transport and reaction control. The results illustrate the potential of using ECH as a low-carbon, scalable, and tunable method for the upgrading of biomass. This study offers valuable insights and guidelines for the rational design of next-generation electrocatalytic systems toward green chemical synthesis and emphasizes promising perspectives for the strategic development of electrochemical technologies in the pathway of a sustainable energy economy. Full article

The development of advanced electrocatalysts plays a pivotal role in enhancing hydrogen production through water electrolysis. In this study, we employed a two-step electrodeposition method to fabricate a 3D porous Cu-Co-Ni alloy with superior catalytic properties and long-term stability for hydrogen evolution reaction (HER). The resulting trimetallic alloy, Cu@Cu-Ni-Co, demonstrated significant improvements in structural integrity and catalytic performance. A comparative analysis of electrocatalysts, including Cu, Cu@Ni-Co, and Cu@Cu-Ni-Co, revealed that Cu@Cu-Ni-Co achieved the best results in alkaline media. Electrochemical tests conducted in 1.0 M NaOH showed that Cu@Cu-Ni-Co reached a current density of 10 mA cm⁻² at a low overpotential of 125 mV, along with a low Tafel slope of 79.1 mV dec⁻¹. The catalyst showed exceptional durability, retaining ~95% of its initial current density after 120 h of continuous operation at high current densities. Structural analysis confirmed that the enhanced catalytic performance arises from the synergistic interaction between Cu, Ni, and Co within the well-integrated trimetallic framework. This integration results in a large electrochemical active surface area (ECSA) of 380 cm² and a low charge transfer resistance (15.76 Ω), facilitating efficient electron transfer and promoting superior HER activity. These findings position Cu@Cu-Ni-Co as a highly efficient and stable electrocatalyst for alkaline HER in alkaline conditions. Full article

This study focuses on making non-precious electrocatalysts for improving the performance of Direct Alcohol Fuel Cells (DAFCs). Specifically, it examines the oxidation of ethanol and methanol. Conventional platinum-based catalysts are expensive and suffer from problems such as degradation and poisoning. To overcome these challenges, we fabricated tri-metallic catalysts composed of nickel, cobalt, and titanium dioxide (TiO₂) embedded in carbon nanofibers (CNFs). The synthesis included electrospinning and subsequent carbonization as well as optimization of parameters to achieve uniform nanofiber morphology and high surface area. Electrochemical characterization revealed that the incorporation of TiO₂ significantly improved electrocatalytic activity for ethanol and methanol oxidation, with current densities increasing from 57.8 mA/cm² to 74.2 mA/cm² for ethanol and from 38.69 mA/cm² to 60.39 mA/cm² for methanol as the TiO₂ content increased. The catalysts showed excellent stability, with the TiO₂-enriched sample (T2) showing superior performance during longer cycling tests. Chronoamperometry and electrochemical impedance spectroscopy are used to examine the stability of the catalysts and the dynamics of the charge carriers. Impedance spectroscopy indicated reduced charge transfer resistance, confirming enhanced activities. These findings suggest that the synthesized non-precious electrocatalysts can serve as effective alternatives to platinum-based materials, offering a promising pathway for the development of cost-efficient and durable fuel cells. Research highlights non-precious metal catalysts for sustainable fuel cell technologies. Full article

Hollow flower-like multi-metallic nanocrystals have attracted significant research attention due to their exceptional catalytic properties, which stem from their high surface area-to-volume ratio and abundant active sites. Nevertheless, conventional synthesis methods for noble metal nanocrystals typically involve complex procedures or require harsh reaction conditions. In this work, we developed a facile and environmentally benign strategy for fabricating hollow flower-shaped trimetallic nanocrystals at ambient temperature. Our approach employs AgCl nanocubes, derived from AgNO₃ and HAuCl₄, as self-sacrificing templates. Through ascorbic acid-mediated reduction of metal precursors, we successfully synthesized three distinct types of hollow flower-like nanocrystals: AuAgCu, AuAgPt, and AuAgPd. Comprehensive characterization confirmed the well-defined morphology and precise composition control of the as-prepared nanocrystals. The catalytic performance was systematically evaluated through in situ UV–vis spectroscopy monitoring of 4-nitrophenylthiophenol reduction, revealing the following activity trend: AuAgCu > AuAgPt > AuAgPd. This study not only provides a versatile platform for constructing sophisticated multi-metallic nanostructures but also offers valuable insights into the structure–activity relationship of complex catalysts. Full article

Chemical sensors, relying on electrical conductance changes in a gas-sensitive material due to the surrounding gas, have the (dis-)advantage of reacting with multiple target gases and humidity. In this work, we report CMOS-integrated SnO₂ thin film-based gas sensors, which are functionalized with mono-, bi-, and trimetallic nanoparticles (NPs) to optimize the sensor performance. The spray pyrolysis technology was used to deposit the metal oxide sensing layer on top of a CMOS-fabricated micro-hotplate (µhp), and magnetron sputtering inert-gas condensation was employed to functionalize the sensing layer with metallic NPs, Ag-, Pd-, and Ru-NPs, and all combinations thereof were used as catalysts to improve the sensor response to carbon monoxide and to suppress the cross-sensitivity toward humidity. The focus of this work is the detection of toxic carbon monoxide and a specific hydrocarbon mixture (HC_mix) in a concentration range of 5–50 ppm at different temperatures and humidity levels. The use of CMOS chips ensures low-power, integrated sensors, ready to apply in cell phones, watches, etc., for air quality-monitoring purposes. Full article

A huge variety of chemical commodities are built from propylene molecules, and its conventional production technologies (naphtha steam cracking and fluid catalytic cracking) are unable to satisfy C₃H₆’s increasing requirements. In this scenario, Direct Propane Dehydrogenation (PDH) provides a practical and reliable route for supplying this short demand due to the economic availability of the raw material (C₃H₈) and the high propylene selectivities. The main challenges of propane dehydrogenation technology are related to the design of very active catalysts with negligible byproduct formation. In particular, the issue of catalyst deactivation by coke deposition still requires further development. In addition, PDH is a considerable endothermic reaction, and the efficiency of this technology is strictly related to heat transfer management. Thus, this current review specifically discusses the recent advances in highly dispersed bimetallic and trimetallic catalysts proposed for the PDH reaction in both conventional-heated and microwave-heated reactors. From the point of view of catalyst development, the recent research is mainly addressed to obtain nanometric and single-atom catalysts and core–shell alloys: atomically dispersed metal atoms promote the desorption of surface-bonded propylene and inhibit its further dehydrogenation. The discussion is focused on the alternative formulations proposed in the last few years, employing active species and supports different from the classical Pt-Sn/Al₂O₃ catalyst. Concerning the conventional route of energy-supply to the catalytic bed, the advantage of using a membrane as well as fluidized bed reactors is highlighted. Recent developments in alternative microwave-assisted dehydrogenation (PDH) employing innovative catalytic systems based on silicon carbide (SiC) facilitate selective heating of the catalyst. This advancement leads to improved catalytic activity and propylene selectivity while effectively reducing coke formation. Additionally, it promotes environmental sustainability in the ongoing electrification of chemical processes. Full article

The catalytic dehydrogenation of NaBH₄ for the generation of H₂ has a lot of potential as a reliable and achievable approach to make H₂, which could be used as a safe and cost-effective energy source in the near future. This work describes the production of unique trimetallic NiCrPd-decorated carbon nanofiber (NiCrPd-decorated CNF) catalysts using electrospinning. The catalysts demonstrated exceptional catalytic activity in generating H₂ through NaBH₄ dehydrogenation. The catalysts were characterized using SEM, XRD, TEM, and TEM-EDX analyses. NiCrPd-decorated CNF formulations have shown higher catalytic activity in the dehydrogenation of NaBH4 compared with NiCr-decorated CNFs. It is likely that the better catalytic performance is because the three metals in the NiCrPd-decorated CNF structure interact with each other. Furthermore, the NiCrPd-decorated CNFs catalyzed the dehydrogenation of NaBH₄ with an activation energy (E_a) of 26.55 KJ/mol. The kinetics studies showed that the reaction is first-order dependent on the dose of NiCrPd-decorated CNFs and zero-order dependent on the concentration of NaBH₄. Full article

Effluent-containing dye molecules is a significant environmental hazard. An economical and energy-saving solution is needed to combat this issue for the purpose of environmental sustainability. In this study, Fe-Ni-Co-based trimetallic nanocomposite was synthesized using the coprecipitation method. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infra-Red spectroscopy were conducted to explore the physical morphology, phase structure and functional groups of the synthesized catalyst. Among dyes, methyl orange is considered as a major contaminant in textile effluent. The current study focused on the degradation of methyl orange using a trimetallic Fe-Ni-Co-based nanocomposite. A central composite design in response surface methodology was employed to analyze the independent variables including dye concentration, catalyst dose, temperature, hydrogen peroxide, irradiation time, and pH. Dye degradation has been achieved up to 81% in 20 min at the lowest initial concentration (5 mg/L) in optimized conditions. Based on ANOVA, the predicted values were in great agreement with the actual values, signifying the applicability of response surface methodology in the photocatalytic decolorization of dyeing effluents. The results gained from this research demonstrated that the synthesis method of trimetallic nanocomposite (Iron Triad) is a cost-effective and energy efficient method that can be scaled up to a higher level for industrial application. Full article

In recent years, nanozymes have attracted particular interest and attention as catalysts because of their high catalytic efficiency and stability compared with natural enzymes, whereas how to use simple methods to further improve the catalytic activity of nanozymes is still challenging. In this work, we report a trimetallic metal–organic framework (MOF) based on Fe, Co and Ni, which was prepared by replacing partial original Fe nodes of the Fe-MOF with Co and Ni nodes. The obtained FeCoNi-MOF shows both oxidase-like activity and peroxidase-like activity. FeCoNi-MOF can not only oxidize the chromogenic substrate 3,3,5,5-tetramethylbenzidine (TMB) to its blue oxidation product oxTMB directly, but also catalyze the activation of H₂O₂ to oxidize the TMB. Compared with corresponding monometallic/bimetallic MOFs, the FeCoNi-MOF with equimolar metals hereby prepared exhibited higher peroxidase-like activity, faster colorimetric reaction speed (1.26–2.57 folds), shorter reaction time (20 min) and stronger affinity with TMB (2.50–5.89 folds) and H₂O₂ (1.73–3.94 folds), owing to the splendid synergistic electron transfer effect between Fe, Co and Ni. Considering its outstanding advantages, a promising FeCoNi-MOF-based sensing platform has been designated for the colorimetric detection of the biomarker H₂O₂ and environmental pollutant TP, and lower limits of detection (LODs) (1.75 μM for H₂O₂ and 0.045 μM for TP) and wider linear ranges (6–800 μM for H₂O₂ and 0.5–80 μM for TP) were obtained. In addition, the newly constructed colorimetric platform for TP has been applied successfully for the determination of TP in real water samples with average recoveries ranging from 94.6% to 112.1%. Finally, the colorimetric sensing platform based on FeCoNi-MOF is converted to a cost-effective paper strip sensor, which renders the detection of TP more rapid and convenient. Full article

This study investigated the production of hydrogen-rich syngas from renewable sources using durable and efficient catalysts. Specifically, the research focused on steam methane reforming (SRM) and dry methane reforming (DRM) of simulated producer gas from biomass steam gasification in a fluidized bed reactor. The catalysts tested are ZSM-5-supported nickel-iron-cobalt-based trimetallic catalysts in different ratios, which were prepared via the wet impregnation method. Synthesized catalysts were characterized using XRD, BET, H₂-TPR, and SEM techniques. The results of the SRM with the simulated producer gas showed that the 20%Ni-20%Fe-10%Co/ZSM-5 trimetallic catalyst, at a gas hourly space velocity (GHSV) of 12 L·h⁻¹·g⁻¹ and reaction temperature of 800 °C, achieved the highest CH₄ conversion (74.8%) and highest H₂ yield (65.59%) with CO₂ conversion (36.05%). Comparing the performance of the SRM and DRM of the simulated producer gas with the 20%Ni-20%Fe-10%Co/ZSM5 at a GHSV of 36 L·h⁻¹·g⁻¹ and 800 °C, they achieved a CH₄ conversion of 67.18% and 64.43%, a CO₂ conversion of 43.01% and 52.1%, and a H₂ yield of 55.49% and 42.02%, respectively. This trimetallic catalyst demonstrated effective inhibition of carbon formation and sintering, with only 2.6 wt.% carbon deposition observed from the thermo-gravimetric analysis of the used catalyst from the SRM of the simulated producer gas, thus promoting the potential of the ZSM-5-supported trimetallic catalysts in methane reforming. Full article

The contamination of industrial water sources with synthetic dyes, such as methylene blue (MB), remains a persistent environmental concern, demanding effective remediation techniques. In response, this research centers on the utilization of trimetallic nanoparticles (TMNPs) composed of Fe-Ni-Cr, Fe-Ni-Cd and Fe-Ni-Cu as a promising solution to address color-related pollution in aquatic ecosystems. These nanoparticles were synthesized using the wet chemical precipitation method and rigorously characterized using Fourier transform infrared (FT-IR), energy-dispersive X-rays (EDX), and scanning electron microscopy (SEM). Armed with these trimetallic nanoparticles, our primary objective was to harness their photocatalytic prowess when exposed to direct sunlight in aqueous environments for the degradation of MB. The progress of photodegradation was meticulously monitored using a reliable visible spectrophotometer, providing insights into the degradation kinetics. Remarkably, within just six hours of solar irradiation, the TMNPs exhibited a remarkable capacity to degrade MB, achieving an impressive degradation rate ranging from 77.5% to 79.4%. In our relentless pursuit of optimization, we conducted a comprehensive examination of various parameters including catalyst dosage, dye dosage, and pH levels, focusing specifically on the Fe-Ni-Cr TMNPs. Through systematic experimentation, a trifecta of optimal conditions emerged: a pH level of 10 (resulting in a 79.35% degradation after 1.5 h), a catalyst amount of 0.005 g (yielding 43.5% degradation after 1.5 h), and a dye concentration of 40.0 ppm (culminating in a 42.54% degradation after 1.5 h). The study also extended its scope to explore the regeneration potential of the catalyst, shedding light on its sustainability in long-term applications. Amidst the vibrant interplay of color and water, TMNPs emerged as a symbol of optimism, offering a promising avenue for the removal of synthetic dyes from the water system. With each experiment and investigation, we inch closer to realizing clearer waters and brighter environmental horizons. Full article

Given the serious harm of toxic phenol to human health and the ecological environment, it is urgent to develop an efficient, low-cost and sensitive nanoenzyme-based method to monitor phenol. MOF-derived nanozyme has attracted wide interest due to its hollow polyhedra structure and porous micro-nano frameworks. However, it is still a great challenge to synthesize MOF-derived multimetal synergistic catalytic nanoenzymes in large quantities with low cost. Herein, we reported the synthetic strategy of porous hollow CA-CoNiMn-CLDHs with ZIF-67 as templates through a facile solvothermal reaction. The prepared trimetallic catalyst exhibits excellent peroxidase-like activity to trigger the oxidative coupling reaction of 4-AAP and phenol in the presence of H₂O₂. The visual detection platform for phenol based on CA-CoNiMn-CLDHs is constructed, and satisfactory results are obtained. The K_m value for CA-CoNiMn-CLDHs (0.21 mM) is lower than that of HRP (0.43 mM) with TMB as the chromogenic substrate. Because of the synergistic effect of peroxidase-like activity and citric acid functionalization, the built colorimetric sensor displayed a good linear response to phenol from 1 to 100 μM with a detection limit of 0.163 μM (3σ/slope). Additionally, the CA-CoNiMn-CLDHs-based visual detection platform possesses high-chemical stability and excellent reusability, which can greatly improve economic benefits in practical applications. Full article

The generation of H₂ via the catalytic hydrolysis of sodium borohydride (SBH) has promise as a practical and secure approach to produce H₂, a secure and environmentally friendly energy source for the foreseeable future. In this study, distinctive trimetallic NiCoPd nanoparticle-supported carbon nanofibers (NiCoPd tri-NPs@CNFs) is synthesized via sol-gel and electrospinning approaches. The fabricated trimetallic catalysts show an excellent catalytic performance for the generation of H₂ from the hydrolysis of SBH. Standard physicochemical techniques were used to characterize the as-prepared NiCoPd tri-NPs@CNFs. The results show that NiCoPd tri-NPs@CNFs is formed, with an average particle size of about 21 nm. When compared to NiCo bimetallic NP @CNFS, all NiCoPd tri-NPs@CNFs formulations demonstrated greater catalytic activates for the hydrolysis of SBH. The improved catalytic activity may be due in the majority to the synergistic interaction between the three metals in the trimetallic architecture. Furthermore, the activation energy for the catalytic hydrolysis of SBH by the NiCoPd tri-NPs@CNFs was determined to be 16.30 kJ mol⁻¹. The kinetics studies show that the reaction is of a first order with respect to the catalyst loading amount and a half order with respect to the SBH concentration [SBH]. Full article

Aiming at developing low-cost, high-performance catalysts for the electrochemical reduction of CO₂ (CO₂-ERR) to valuable multicarbon (C₂–C₃) chemicals to alleviate global warming, trimetallic alloy electrocatalysts containing Cu, Ni, and Sn supported on a Pd-activated carbon fabric substrate (CS) were prepared via an electroless deposition method. The as-deposited CuNiSn/CS electrocatalysts were employed in CO₂-ERR in an H-cell type reactor at an applied potential of −1.6 V vs. Ag/AgCl. The effect of the electroless deposition time (15, 30, and 45 min) was investigated, finding no significant structural differences according to the X-ray diffraction patterns. The evaluation of the reaction performance via linear sweep voltammetry revealed that CO₂ was more effectively reduced to adsorbed species on the catalytic surface sites of the electrocatalyst prepared with a 30 min deposition time. The analysis of the gas and liquid products via gas chromatography and nuclear magnetic resonance, respectively, revealed that the Faradaic efficiency and H₂ production over CuNiSn/CS was lower than those over related bimetallic and monometallic electrocatalysts, indicating the inhibition of the competitive H₂ evolution reaction. Liquid products including formate, ethylene glycol, acetone, ethanol, acetate, and 1-buthanol were detected. Full article