Bimetallic Nanocatalysts Research Articles

Impact of Surface Composition Changes on the CO2-Reduction Performance of Au-Cu Aerogels.

Over the past decades, the electrochemical CO2-reduction reaction (CO2RR) has emerged as a promising option for facilitating intermittent energy storage while generating industrial raw materials of economic relevance such as CO. Recent studies have reported that Au-Cu bimetallic nanocatalysts feature a superior CO2-to-CO conversion as compared with the monometallic components, thus improving the noble metal utilization. Under this premise and with the added advantage of a suppressed H2-evolution reaction due to absence of a carbon support, herein, we employ bimetallic Au3Cu and AuCu aerogels (with a web thickness ≈7 nm) as CO2-reduction electrocatalysts in 0.5 M KHCO3 and compare their performance with that of a monometallic Au aerogel. We supplement this by investigating how the CO2RR-performance of these materials is affected by their surface composition, which we modified by systematically dissolving a part of their Cu-content using cyclic voltammetry (CV). To this end, the effect of this CV-driven composition change on the electrochemical surface area is quantified via Pb underpotential deposition, and the local structural and compositional changes are visually assessed by employing identical-location transmission electron microscopy and energy-dispersive X-ray analyses. When compared to the pristine aerogels, the CV-treated samples displayed superior CO Faradaic efficiencies (≈68 vs ≈92% for Au3Cu and ≈34 vs ≈87% for AuCu) and CO partial currents, with the AuCu aerogel outperforming the Au3Cu and Au counterparts in terms of Au-mass normalized CO currents among the CV-treated samples.

Biosynthesis of Pt doped Zn bimetallic nanoparticles by using Polygonum glabrum extract for colorimetric, fluorimetric (Ni2+, Hg2+ and Fe2+) ions sensing and photocatalytic degradation of organic dye with electrochemical techniques

In the present study we aimed to explore the biosynthesis and characterization of monometallic platinum nanoparticles (PtNPs), zinc oxide nanoparticles (ZnONPs) are compared to the Pt doped ZnONPs (Pt-ZnONPs) and its sensing, electrochemical, photocatalytic properties. The bimetallic Pt-ZnONPs was synthesized by using Polygonum glabrum leaves extract; it acts as reducing agent and stabilizing agent. The analysis of colorimetric and fluorimertic sensing methods to determine the highly detection of Ni2+, Hg2+ and Fe2+ ions. The optical properties were characterized by UV-visible, FT-IR, XRD, XPS, SEM-EDX and TEM-SAED analysis. The synthesized monometallic PtNPs and ZnONPs are well dispersed spherical and hexagonal particles with sizes ranging from 8 nm to 25 nm. Electrochemical analysis were carried out the synthesized monometallic and bimetallic Pt-ZnONPs oxidation with reduction potentials by using cyclic voltammetry with UV-visible absorption spectroscopy based on band gap energy to calculation of LUMO and HOMO energy levels. The photocatalytic activities with band gap energy 96% for MeB indicated that only Pt doped ZnONPs for bimetallic Pt-ZnONPs nanocatalyst as compared to monometallic PtNPs and ZnONPs for single metal nanocatalyst actions. The highly sensitivity of Ni2+, Hg2+ and Fe2+ ions are combined with synthesized NPs extended to the oxidation-reduction potential for Pt2+ by Zn2+ ions may find sensitivity for trace different metal ions of pollution level with environmental sensing and photocatalytic applications.

Efficient degradation of tetracycline by activated peroxymonosulfate with high permeate flux FeTiOx reactive ceramic membrane: Membrane preparation, real wastewater application, and mechanism insight

Antibiotic residue in wastewater is one of the most worrying environmental pollution problems. In this study, innovative bimetallic nanocatalysts of FeTiOx were prepared. Benefiting from the synergistic effect between Ti and Fe, FeTiOx exhibited an excellent performance in activating peroxymonosulfate (PMS) for tetracycline (TC) degradation. Within 60 min, the TC treatment efficiency can reach 96 %. Mechanism study confirmed that the non-free radical pathway (1O2) and free radical pathway (O2−, OH, SO4−) co-participated during the TC treatment process. To further improve the separation function and efficiency, FeTiOx nanocatalyst was loaded on the ceramic membrane (CM) by a facile spraying method and a self-designed experimental device was constructed, which can be used to degrade TC with large volume. In the designed device, 2 L 40 mg/L TC wastewater can be degraded at one time with an efficiency of 85 % and a permeate flux of 1011.66 kg/m2·h when the transmembrane pressure (TMP) was 20 kPa. Finally, real pharmaceutical wastewater was treated and found that the removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3−N) and total organic carbon (TOC) were 70.3 %, 62.85 % and 32.8 %, respectively. The study provides a new strategy for treating wastewater pollutants by combining CM technology with advanced oxidation processes (AOPs).

Significantly improved dehydrogenation of dodecyl-N-ethylcarbazole over supported PdFe bimetallic nanocatalysts via polydopamine surface modification of Al2O3

N-ethylcarbazole (NEC) has great application prospects in hydrogen storage due to its ability to dehydrogenate at lower energy and high hydrogen storage performance. Developing supported metal catalysts with high catalytic activity and stability is key to achieving large-scale application of LOHC hydrogen storage technology. In this paper, bimetallic FePd/Al2O3@PDA-GR catalysts used for the dehydrogenation process of 12H-NEC were prepared by stepwise reduction methods, including chemical reduction and galvanic replacement, using PDA-coated Al2O3 as the support. The characterization results showed that adding PDA could anchor the metal particles, improve the dispersion of metal particles on the support surface, and reduce the agglomeration phenomenon. The nanoparticles of bimetallic catalysts prepared by the galvanic replacement were small, with the particle size distribution of 0.86 nm-2.78 nm, and an average size of 1.52 nm. The large number of exposed active sites enabled the catalysts to reduce the dosage of Pd while still possessing excellent catalytic performance. And part of Pd was coated on Fe NPs in the Fe5Pd1/Al2O3@PDA-GR catalysts prepared by galvanic replacement, which improved the atom utilization of Pd. And there is an obvious electronic interaction between Fe and Pd. In the dehydrogenation process of 12H-NEC to NEC, The prepared FePd/Al2O3@PDA-GR catalyst exhibited excellent catalytic performance and had a significantly greater dehydrogenation efficiency than found in the literature, 95% for 1 h and 100% for 3 h at 180 °C. The temperature drop to 160 °C did not affect the dehydrogenation efficiency, which remained at 98.1% for 3 h. The prepared catalyst had good stability, and the dehydrogenation efficiency was 93.1% after five successive cycles.

Self-assembled FeRu bimetallic nanocatalysts for efficient and durable mutual CO–CO2 conversion in a reversible solid oxide electrochemical cell

Self-assembled FeRu bimetallic nanocatalysts for efficient and durable mutual CO–CO2 conversion in a reversible solid oxide electrochemical cell

Synthesis and photocatalytic properties of zinc-copper bimetallic oxide nanoparticles for removal of reactive blue 19 dye in aqueous suspension

ABSTRACT This research investigates the photocatalytic removal of reactive blue 19 (RB19) dye utilising Zn-Cu (zinc-copper) bimetallic oxide nanocatalysts under UV irradiation. The nanocatalysts were prepared via the co-precipitation technique and thoroughly characterised using different procedures including XRD, FTIR, BET-BJH, FESEM, TEM, and EDX. BET-BJH analysis revealed a specific surface area of 59.774 m2/g for the Zn-Cu bimetallic oxide nanocatalyst. Response surface methodology (RSM) was employed to optimise operational factors such as catalyst amount, pH, H2O2 amount, and UV power, with a quadratic model showing high reliability (R2 = 0.89). Under optimal conditions (4 mg catalyst amount, pH 6.68, 0.42 mL H2O2 dose, 23 W UV power, and 45 min reaction time), the maximum RB19 removal reached 77.14%, increasing to 98.33% after 120 min. The kinetic study revealed a reaction rate constant of 0.884 min−1, indicating efficient removal. Zn-Cu bimetallic oxides demonstrated superior RB19 removal capacity, with only a 5.92% reduction in removal yield after 5 consecutive reuse cycles. This study underscores the potential of Zn-Cu bimetallic oxide nanocatalysts for efficient removal of RB19 dye in suspension media.

Unveiling the Dynamic Electrocatalytic Activity of Online Synthesized Bimetallic Nanocatalysts via Electrochemiluminescence Microscopy.

Effective bimetallic nanoelectrocatalysis demands precise control of composition, structure, and understanding catalytic mechanisms. To address these challenges, we employ a two-in-one approach, integrating online synthesis with real-time imaging of bimetallic Au@Metal core-shell nanoparticles (Au@M NPs) via electrochemiluminescence microscopy (ECLM). Within 120 s, online electrodeposition and in situ catalytic activity screening alternate. ECLM captures transient faradaic processes during potential switches, visualizes electrochemical processes in real-time, and tracks catalytic activity dynamics at the single-particle level. Analysis using ECL photon flux density eliminates size effects and yields quantitative electrocatalytic activity results. Notably, a nonlinear activity trend corresponding to the shell metal to Au surface atomic ratio is discerned, quantifying the optimal surface component ratio of Au@M NPs. This approach offers a comprehensive understanding of catalytic behavior during the deposition process with high spatiotemporal resolution, which is crucial for tailoring efficient bimetallic nanocatalysts for diverse applications.

In situ Tracking the Constrained Reconstruction of Cu3Pd@SiO2 Nanoparticles Driven by Redox Atmospheres

AbstractEndowed with flexible surface coordination and synergetic electronic status, bimetallic particles serve as promising heterogeneous catalysts as their microstructures evolved sensitively to the treatment atmospheres, whereas knowledge of dynamic manners is less. Herein, utilizing environmental transmission electron microscopy (ETEM), the reconstructions of Cu3Pd particles in oxidization/reduction atmospheres were explored at atomic scale. Specifically, bare Cu3Pd particles went through a phase separation of CuOx and PdOx during in situ oxidation, and subsequent agglomeration after H2 reduction. While protected in a silica shell, the confined Cu3Pd particles were oxidized into Cu1.5Pd0.5O2 phase after air calcination and subsequently restructured into versatile configurations during H2 reduction. Specifically, hollow Cu3Pd alloy architecture with Pd enriched layer near surface as reduced at 200 °C. Further rising 400 to 600 °C, it yielded disordered Cu3Pd alloys with slightly Pd atoms enrichment at outmost surface. The dynamical behaviors of single Cu1.5Pd0.5O2 particle during in situ reduction have been visualized in ETEM, wherein a series of deformation, elongation and rotation is involved during the hollow architecture firstly formation, and then vanished into a Cu3Pd solid solution nanoparticle. The tunable microstructures of Cu3Pd@SiO2 driven by redox atmospheres demonstrate efficient approach for precisely regulating the chemical environments of constrained bimetallic nanocatalysts.

New Design PdNi Heterogeneous Nanocatalysts for the Direct Synthesis of Hydrogen Peroxide

Hydrogen peroxide (H2O2) is a widely used chemical as an eco-friendly oxidizing agent, with water being the only byproduct of oxidation in applications like bleaching pulp and paper, making electronic semiconductors, chemical and detergent synthesis, and wastewater treatment. The direct synthesis approach is preferred to provide the environmentally friendly production of H2O2 for market requirements. Bimetallic PdNi nanocatalysts were chosen for this study because of their catalytic activity and the structural characteristics of the material system. First, for the development of order-structured bimetallic PdNi nanocatalysts based on mesoporous carbon template after hydrogen-assisted heat treatment at 750∘C. The transformation of the disordered structure into ordered intermetallically structured PdNi alloys with higher alloying extents was confirmed by X-ray absorption spectroscopy (XAS) and high-resolution transition electron microscopy (HR-TEM). Then, to improve the oxygen oxidation reaction, two-electron pathway selectivity was used by TiO2-C as a support-ordered structure material to facilitate strong metal-support interactions. XAS and X-ray photoelectron spectra (XPS) techniques show more clear evidence of metal-support interactions with electron transfer from defects in the TiO2-C support to the ordered alloyed PdNi nanocatalysts, resulting in record productivity and selectivity of H2O2 production at ambient conditions. The results demonstrated in this study will enlighten a reliable design of new heterogeneous nanocatalysts with ordered structure. Electron transfer between hybrid support and active sites can clarify the catalytic behavior and prompt further research during the direct synthesis of hydrogen peroxide.
 Keywords: hydrogen peroxide, direct synthesis, heterogeneous nanocatalysts PdNi, TiO2-C

Insights in the removal of micropollutants using Fe0+Au0@BN heterojunction: A synergistic in the photo-Fenton-like system

Recently, contamination of aquatic habitats by antibiotics, particularly tetracyclines and cancer-causing compounds, n-(n-propyl) thiourea, has caused serious concerns. The primary objective of the current investigation is to obtain an efficient method of removing these contaminants from waterbodies using the novel bimetallic heterojunction nanocatalyst supported by bentonite clay. A greener route using Psidium guajava extract reduces the precursor ions, viz., iron and gold, to Fe0 and Au0 in synthesizing composite material (Fe0+Au0@BN). The catalyst (Fe0+Au0@BN) shows a band gap energy of 1.85 eV. Nevertheless, using nanocomposite material under visible light irradiations, the photo-Fenton-like process efficiently degrades the n-(n-propyl) thiourea and tetracycline. The method enables achievement of a high degradation efficacy for both the micro-pollutants and allows very high mineralization of these pollutants, and the multiple parameters, such as pH, catalyst dosage, and H2O2 concentration, optimize the degradation process. Repeated usage of the nanocomposite material with no significant change in efficiency showed the high stability and reusability of the nanocatalyst. Furthermore, the material showed high suitability in natural water samples to decontaminate water contaminated with these two contaminants: n-(n-propyl) thiourea and tetracycline.

Revealing the heterogeneous catalytic kinetics of PtRu nanocatalysts at the single particle level.

Comparison of the structural features and catalytic performance of bimetallic nanocatalysts will help to develop a unified understanding of structure-reaction relationships. The single-molecule fluorescence technique was utilized to reveal the differences in catalytic kinetics among PtRu bimetallic nanocatalysts and Pt and Ru monometallic nanocatalysts at the single particle level. The results show that bimetallic nanocatalysts have higher apparent rate constants and desorption rate constants relative to monometallic nanocatalysts, which leads to their higher catalytic activity. At the single particle level, bimetallic nanocatalysts have a wider distribution of apparent rate constants, suggesting that bimetallic nanocatalysts have higher activity heterogeneity relative to monometallic nanocatalysts. By investigating the relationship between the reaction rate and the rate of dynamic activity fluctuations, it was found that spontaneous surface restructuring and reaction-induced surface restructuring of nanoparticles occurred. The surface of bimetallic nanoparticles restructured faster, which made the bimetallic nanocatalysts more active. These findings provide new insights into the design of highly active bimetallic nanocatalysts.

Total oxidation of toluene at low temperatures in air using sono-impregnated Mn/Cu bimetal over activated clinoptilolite as a nanocatalyst: Designing the oxidation reaction rate with the optimization of the fixed bed reactor CFD model

A series of manganese-copper oxides on clinoptilolite with various impregnation sequences were synthesized using ultrasonic irradiation. Their properties were characterized by XRD, BET, FTIR, FESEM, and EDX techniques. The XRD patterns confirmed the formation of Mn2O3/MnO and CuO as the crystalline phase on clinoptilolite. FESEM images confirmed that manganese and copper dispersed on support in nano-range size. EDX results indicated uniform dispersion of the elements. FTIR patterns demonstrated that surface groups of nanocatalysts agree with the patterns of metals and support applied in nanocatalysts synthesis. Catalysts were investigated in the oxidation of toluene from the polluted air. Results showed that bimetallic nanocatalysts are more active than single metal oxide nanocatalysts) Mn2O3/MnO/CuO(causing the synergism effect of active phases. The highest catalytic activity was observed on the Mn/Cu/CLT nanocatalyst in which excess manganese oxide as active sites existed on the support and led to a decreased complete oxidation temperature of toluene. The result of toluene oxidation from the polluted air demonstrated that the prepared nanocatalyst was very active and stable. Also, the Mars–Van Krevelen kinetic model and the calculated kinetic parameters of this model were used to develop and express the toluene catalytic oxidation reaction rate on newly synthesized catalysts using the combination of CFD method with an intelligent genetic optimization algorithm. All results obtained using this method have an RMSE less than 0.1. Also, the activation energy based on the Arrhenius law for the toluene oxidation reaction using the Mn/Cu/CLT optimal nanocatalyst was calculated by this method equal to 98480 J/mol with RMSE 0.0248.

Two-dimensional titanium carbide-supported ultrafine non-noble bimetallic nanocatalysts for remarkable hydrolytic evolution from ammonia borane

Cu0.9Ni0.1/Ti3C2Tx catalysts exhibit an impressive turnover frequency (TOF) of 2429 h−1 at 323 K for AB hydrolysis due to the synergistic effect between Cu and Ni, as well as strong electronic metal–support interactions between Ti3C2Tx and CuNi NPs.

Insight into activation of peroxymonosulfate by Fe2O3 and MoN co-doped nitrogen-rich carbon to removal of bisphenol A: Singlet oxygen and electron transfer

In this study, zeolite imidazolate framework-8 (ZIF-8) was utilized as a nitrogen-rich porous carbon substrate (NC) loaded with Fe2O3 and MoN to prepare bimetallic nanocatalysts (FeMo@NC) with synergistic catalytic effect. The optimized Fe0.05Mo0.05 @NC exhibited excellent performance in activating PMS and could completely remove BPA from water within 60 min. The results showed that the introduction of molybdenum significantly lowered the energy barrier for the generation of 1O2 and significantly increased the degree of graphitization and specific surface area of the catalysts, which facilitated the direct electron transfer and adsorption of target substances. The electron transfer of the surface complexes and 1O2 jointly induced the non-radical oxidation of BPA. In addition, the system was suitable for a wide pH range (pH=3–9) and resistant to background organic matter in wastewater. Our work elucidated the mechanism of transition metal Mo to enhance the catalytic performance of heterogeneous iron-based catalysts, which provided a new aspect for the development of catalysts with high efficiency for PMS activation.

Tuning Pd-to-Ag Ratio to Enhance the Synergistic Activity of Fly Ash-Supported PdxAgy Bimetallic Nanoparticles.

Fly ash (FA)-supported bimetallic nanoparticles (PdxAgy/FA) with varying Pd:Ag ratios were prepared by coprecipitation of Pd and Ag involving in situ reduction of Pd(II) and Ag(I) salts in aqueous medium. All the supported nanoparticles were thoroughly characterized with the aid of powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), electron microscopy (field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM)), and elemental analyses, which include inductively coupled plasma-optical emission spectroscopy (ICP-OES) and energy-dispersive X-ray spectroscopy (EDS). A gradual broadening and shifting of PXRD peaks, ascribable to Ag, to higher angles with an increase in the Pd:Ag ratio affirms the alloying of interface between Pd and Ag nanoparticles. The coexistence of Pd and Ag was further confirmed by EDS elemental mapping as well as by the presence of bimetallic lattices on the FA surface, as evident from the high-resolution TEM analysis. The dependency of crystallite size and average size of bimetallic nanoparticles on Ag loading (mol %) was elucidated with the help of a combination of PXRD and TEM studies. Based on XPS analysis, the charge transfer phenomenon between contacting Pd-Ag sites could be evident from the shifting of 3d core electron binding energy for both Pd and Ag compared with monometallic Pd and Ag nanoparticles. Following a pseudo-first-order reaction kinetics, all the nanocatalysts were able to efficiently reduce 4-nitrophenol into 4-aminophenol in aqueous NaBH4. The superior catalytic performance of the bimetallic nanocatalysts (PdxAgy/FA) over their monometallic (Pd100/FA and Ag100/FA) analogues has been demonstrated. Moreover, the tunable synergistic effect of the bimetallic systems has been explored in detail by varying the Pd:Ag mol ratio in a systematic manner which in turn allowed us to achieve an optimum reaction rate (k = 1.050 min-1) for the nitrophenol reduction using a Pd25Ag75/FA system. Most importantly, all the bimetallic nanocatalysts explored here exhibited excellent normalized rate constants (K ≈ 6000-15,000 min-1 mmol-1) compared with other supported bimetallic Pd-Ag nanocatalysts reported in the literature.

Graphene Oxide from Graphite of Spent Batteries as Support of Nanocatalysts for Fuel Hydrogen Production

The increasing production of electronic waste and the rising demand for renewable energy are currently subjects of debate. Sustainable processes based on a circular economy are required. Then, electronic devices could be the main source for the synthesis of new materials. Thus, this work aimed to synthesize graphene oxide (GO) from graphite rod of spent Zn-C batteries. This was used as support for Ni/Co bimetallic nanocatalysts in the evolution of hydrogen from NaBH4 for the first time. The graphene oxide (GO) exhibited a diffraction peak at 2θ = 9.1°, as observed using X-ray diffraction (XRD), along with the presence of oxygenated groups as identified using FTIR. Characteristic bands at 1345 and 1574 cm−1 were observed using Raman spectroscopy. A leaf-shaped morphology was observed using SEM. GO sheets was observed using TEM, with an interplanar distance of 0.680 nm. Ni/Co nanoparticles, with an approximate size of 2 nm, were observed after deposition on GO. The material was used in the evolution of hydrogen from NaBH4, obtaining an efficiency close to 90%, with a kinetic constant of 0.0230 s−1 at 296.15 K and activation energy of 46.7 kJ mol−1. The material showed an efficiency in seven reuse cycles. Therefore, a route of a new material with added value from electronic waste was obtained from an eco-friendly process, which can be used in NaBH4 hydrolysis.

Cysteine and Ionic Liquid Modified Magnetic Nanoparticles Supported RuCu as a New Bimetallic Catalyst in Reduction Reactions

In this study, bimetallic RuCu supported on L-cysteine functionalized ionic liquid modified magnetic nanoparticles (Fe3O4@IL-Cys-RuCu) was successfully synthesized and characterized. This bimetallic nanocatalyst showed excellent activity in the reduction of 2,3, and 4-nitrophenol isomers and organic dyes as well as catalytic degradation of tetracycline (TC) at room temperature in water. Using this catalyst, complete reduction of nitrophenols was achieved within 9-16 min and degradation of organic dyes and tetracycline were accomplished within 7-4 and 30 minutes, respectively. The superior activity of bimetallic RuCu compared to similar Ru and Cu catalysts was proved and results indicated that the based on type of reaction, bimetallic catalyst was 2-33 times more efficient than the corresponding monometallic catalysts. This catalyst was recovered and recycled up to 14 times without decreasing in the catalytic activity and stability of the reused catalyst was confirmed by TEM, XRD and XPS.

Highly efficient dehydrogenation of dodecahydro-N-ethylcarbazole over Al2O3 supported PdCo bimetallic nanocatalysts prepared by galvanic replacement

NEC is one of the most promising liquid organic hydrogen storage materials. The highly efficient and low cost dehydrogenation catalysts are crucial for large-scale hydrogen storage. In this paper, Co/Al2O3 precursors were prepared by chemical reduction, and then a series of Pd1Con/Al2O3 catalysts for 12H-NEC dehydrogenation was prepared by galvanic replacement of Pd2+ using Co as a template and reducing agent. The prepared catalysts were characterized by TEM, FT-IR, XPS, H2-TPR and H2-TPD. The results demonstrated that Pd1Con NPs were uniformly dispersed over the surface of Al2O3 in the form of Co@Pd core-shell structure, CoPd alloy and PdNPs, with an average particle size of 2.78 nm. The electron transfer occurred between Co and Pd. For the dehydrogenation of H12-NEC, the produced Pd1Co5/Al2O3 catalyst exhibited excellent catalytic activity. The dehydrogenation efficiency was 100% at 180 °C for 3 h and 98.5% at 150 °C for 6 h, and TOF reached 1.414 gH2/gPd min−1, which was significantly higher than that of monometallic Pd/Al2O3 catalysts and that reported in the literature. The kinetic studies of the catalytic 12H-NEC dehydrogenation showed that 4H-NEC→NEC is the rate-limiting step with the highest apparent activation energy of 68.72 kJ/mol. The hydrogen release efficiency remained essentially unchanged after four cycles.

Enlightening the performance-boosting effect of electroactivation approaches on the electrooxidation of methanol reaction in acidic media catalyzed by cobalt-tin bimetallic nanocatalysts

This research investigates the impact of electrochemical activation on cobalt-tin (Cox-Sn100-x) bimetallic nanocatalysts for the methanol oxidation reaction (MOR) in acidic conditions. Two electroactivation protocols, namely activation in a phosphate buffer (PB) solution and in-situ activation, using chronoamperometry, were developed. The electrochemical performance of the MOR electrocatalyst was evaluated through cyclic voltammetry analysis within a specific electrode potential range. Optimal activation conditions for the PB solution were achieved at a pH of 3.0 and an activation potential of −1.3 V (vs. Ag/AgCl), while the in-situ activation process showed the best results at an activation potential of −0.7 V (vs. Ag/AgCl). Both the in-situ and PB electroactivated Co65–Sn35 catalysts exhibited significant enhancements in MOR activity, with the in-situ activation resulting in a 10-fold increase and the PB activation leading to an 8.5-fold increase. The proposed mechanism for this substantial enhancement involves simultaneous hydrogen evolution and water electrolysis during the electroactivation treatments of the Co65–Sn35 electrocatalyst. In fact, the formation of OHads species during the electroactivation treatment could provide a fraction of OHads which was essential for the MOR. These findings might present opportunities for the engineering and design of bimetallic noble metal-free nanocatalysts for efficient utilization in high-performance acidic direct methanol fuel cells (DMFCs).

An extensive comparison of green Pt-Ag mono and bimetallic nanoparticles from Naringi crenulata extract for highly detection of Cu2+, Pb2+ and Mg2+ ions in water samples and photocatalytic reduction of organic pollutants for environmental application.

BackgroundIn this study, the green synthesis of mono Platinum Nanoparticles (PtNPs), Silver Nanoparticles (AgNPs) and bimetallic Pt-AgNPs are synthesized by using Naringi crenulata extract act as reducing, capping and stabilizing agent. Hence, the Pt-AgNPs prepared by the green synthesized method is expected to be eco-friendly and have potential photocatalytic reduction with degradation activity against environmental organic pollutant 4-Nitrophenol. MethodsThe synthesized mono PtNPs, AgNPs and bimetallic Pt-AgNPs were characterized by UV–Vis spectroscopy, FTIR spectroscopy, XRD, XPS, SEM, EDX and TEM analysis. The appearances of highly, sensitivity and metal ion concentration were considered to determine the optimum conditions of the synthesized of PtNPs-Cu2+, AgNPs-Pb2+ and Pt-AgNPs-Mg2+. Significant FindingsThe green synthesis of Pt-Ag bimetallic nanoparticles (Pt-AgNPs) can be expedited by the reduction of Pt4+ and Ag+ metal ions to Pt-AgNPs takes place allowing to their reduction oxidation potential. The TEM analysis of Pt-AgNPs shows homogeneous oval and spherical irregular shaped with particle size 6–22 nm. Under UV–Vis the light source, the attained bimetallic Pt-AgNPs active nanocatalyst had an effective photocatalytic reduction and degradation activity against organic contaminant in the environment.