Activity For Methanol Oxidation Research Articles

Led-induced deposition of Pt and Au NPs on carbon fibers: Developing a novel strategy for facile fabrication of electrocatalysts for enhanced methanol electrooxidation

In addressing the imperative of aligning materials science with sustainable development, our study introduces an innovative method for the simultaneous deposition of Pt and Au nanoparticles onto a carbon support. This research represents the pioneering application of the photodeposition process for synthesizing bimetallic nanoparticles on a carbon matrix. The comprehensive characterization of the resulting nanostructures involves various techniques, including field X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), atomic force microscopy (AFM), energy-dispersive X-ray analysis (EDX), inductively coupled plasma atomic emission spectroscopy (ICP-OES), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetric techniques. Our findings reveal that the photodeposition method produces a homogeneous AuPt nanostructure, demonstrating superior electrocatalytic activity in methanol oxidation compared to the monometallic carbon fiber_Pt (CF_Pt) catalyst. These results emphasize the effectiveness of our novel approach in fabricating electrocatalysts with exceptional performance in methanol oxidation reactions.

Supported palladium nanocubes reduced by graphene oxide and surface-cleaned for enhanced electrocatalytic activity

Highly dispersed Pd nanocubes (Pd NCs) supported on the surface of partially reduced graphene oxide (pRGO) were successfully prepared by a facile procedure. GO was used as reductant and support without any other external reducing agent been introduced, and potassium iodide (KI) was used as capping agent for morphology control respectively. Catalytic activities for ethanol oxidation and methanol oxidation were greatly enhanced after excess iodine on the surface of Pd NCs was removed by being surface-treated with NaBH4 solution.

Regulating Oxygen Activity of Perovskites to Promote Activity and Selectivity for Methanol Oxidation to Formaldehyde

Regulating Oxygen Activity of Perovskites to Promote Activity and Selectivity for Methanol Oxidation to Formaldehyde

Green and sustainable use of macadamia nuts as support material in Pt-based direct methanol fuel cells

The successful commercialization of direct methanol fuel cells (DMFCs) is hindered by inadequate methanol oxidation activity and anode catalyst longevity. Efficient and cost-effective electrode materials are imperative in the widespread use of DMFCs. While Platinum (Pt) remains the primary component of anodic methanol oxidation reaction (MOR) electrocatalysts, its utilization alone in DMFC systems is limited due to carbon monoxide (CO) poisoning, instability, methanol crossover, and high cost. These limitations impede the economic feasibility of Pt as an electrocatalyst. Herein, we present the use of powdered activated carbon (PAC) and granular activated carbon (GAC), both sourced from macadamia nut shells (MNS), a type of biomass. These bio-based carbon materials are integrated into hybrid supports with reduced graphene oxide (rGO), aiming to enhance the performance and reduce the production cost of the Pt electrocatalyst. Electrochemical and physicochemical characterizations of the synthesized catalysts, including Pt-rGO/PAC-1:1, Pt-rGO/PAC-1:2, Pt-rGO/GAC-1:1, and Pt-rGO/GAC-1:2, were conducted. X-ray diffraction analysis revealed crystallite sizes ranging from 1.18 nm to 1.68 nm. High-resolution transmission electron microscopy (HRTEM) images with average particle sizes ranging from 1.91 nm to 2.72 nm demonstrated spherical dispersion of Pt nanoparticles with some agglomeration across all catalysts. The electrochemical active surface area (ECSA) was determined, with Pt-rGO/GAC-1:1 exhibiting the highest ECSA of 73.53 m2 g−1. Despite its high ECSA, Pt-rGO/GAC-1:1 displayed the lowest methanol oxidation reaction (MOR) current density, indicating active sites with poor catalytic efficiency. Pt-rGO/PAC-1:1 and Pt-rGO/PAC-1:2 exhibited the highest MOR current densities of 0.77 mA*cm−2 and 0.74 mA*cm−2, respectively. Moreover, Pt-rGO/PAC-1:2 and Pt-rGO/PAC-1:1 demonstrated superior electrocatalytic mass (specific) activities of 7.55 mA/mg (0.025 mA*cm−2) and 7.25 mA/mg (0.021 mA*cm−2), respectively. Chronoamperometry tests revealed Pt-rGO/PAC-1:2 and Pt-rGO/PAC-1:1 as the most stable catalysts. Additionally, they exhibited the lowest charge transfer resistances and highest MOR current densities after durability tests, highlighting their potential for DMFC applications. The synthesized Pt supported on PACs hybrids demonstrated remarkable catalytic performance, stability, and CO tolerance, highlighting their potential for enhancing DMFC efficiency.

Investigation of Pd2B- and NiB-Doped Pd–Ni/C Electrocatalysts with High Activity for Methanol Oxidation

Investigation of Pd₂B- and NiB-Doped Pd–Ni/C Electrocatalysts with High Activity for Methanol Oxidation

Breaking Continuously Packed Bimetallic Sites to Singly Dispersed on Nonmetallic Support for Efficient Hydrogen Production.

We have synthesized Pt1Zn3/ZnO, also termed 0.01 wt %Pt/ZnO-O2-H2, as a catalyst containing singly dispersed single-atom bimetallic sites, also called a catalyst of singly dispersed bimetallic sites or a catalyst of isolated single-atom bimetallic sites. Its catalytic activity in partial oxidation of methanol to hydrogen at 290 °C is found to be 2-3 orders of magnitude higher than that of Pt-Zn bimetallic nanoparticles supported on ZnO, 5.0 wt %Pt/ZnO-N2-H2. Selectivity for H2 on Pt1Zn3/ZnO reaches 96%-100% at 290-330 °C, arising from the uniform coordination environment of single-atom Pt1 in singly dispersed single-atom bimetallic sites, Pt1Zn3 on 0.01 wt %Pt/ZnO-O2-H2, which is sharply different from various coordination environments of Pt atoms in coexisting PtxZny (x ≥ 0, y ≥ 0) sites on Pt-Zn bimetallic nanoparticles. Computational simulations attribute the extraordinary catalytic performance of Pt1Zn3/ZnO to the stronger adsorption of methanol and the lower activation barriers in O-H dissociation of CH3OH, C-H dissociations of CH2O to CO, and coupling of intermediate CO with atomic oxygen to form CO2 on Pt1Zn3/ZnO as compared to those on Pt-Zn bimetallic nanoparticles. It demonstrates that anchoring uniform, isolated single-atom bimetallic sites, also called singly dispersed bimetallic sites on a nonmetallic support can create new catalysts for certain types of reactions with much higher activity and selectivity in contrast to bimetallic nanoparticle catalysts with coexisting, various metallic sites MxAy (x ≥ 0, y ≥ 0). As these single-atom bimetallic sites are cationic and anchored on a nonmetallic support, the catalyst of singly dispersed single-atom bimetallic sites is different from a single-atom alloy nanoparticle catalyst. The critical role of the 0.01 wt %Pt in the extraordinary catalytic performance calls on fundamental studies of the profound role of a trace amount of a metal in heterogeneous catalysis.

Enhanced solar light-induced performance of a step-scheme heterojunction nanostructure (C3N4/ZrO2) for mixed dye degradation and methanol oxidation

This study focuses on the high demand for innovative nanostructured materials with boosted photocatalytic performance for the degradation of organic pollutants and oxidation of organic compounds. A nanostructure consisting of graphitic carbon nitride (C3N4) and zirconium oxide (ZrO2) denoted as C3N4/ZrO was synthesized via direct thermal pyrolysis. A comprehensive array of characterization techniques (XRD, FESEM, HRTEM and UV-DRs analysis) was utilized for a detailed analysis of the prepared photocatalysts. The photoactivity of the C3N4/ZrO nanostructure was explored by the photocatalytic degradation of a mixture of dyes (Rh B + CV), and methanol oxidation reaction and compared with those of pristine C3N4 and ZrO2. The photoactivity of C3N4/ZrO for degrading the mixed dye under simulated solar light was 97% higher than those of pristine C3N4 (88%) and ZrO2 (31%). The C3N4/ZrO nanostructure, functioning as a step-scheme heterojunction, demonstrated superior photocatalytic performance due to enhanced charge transport facilitated by robust interfacial contact between C3N4 and ZrO2. This enhanced photodegradation efficiency, reaching 97%, establishes a foundation for the development of heterojunction catalysts with exceptional photocatalytic activities. Furthermore, the methanol oxidation activity of the C3N4/ZrO nanostructure was exceptionally high, yielding a 138.25 mA/cm2 current density at a 2 M methanol. The proposed material has a high application potential for mitigating pollution and energy issues.

Microwave Assisted Synthesis of PtxRu1−x-NiTiO3: A Novel Hybrid Nanostructured Electrocatalyst for Direct Methanol Oxidation

In the present investigation, we have explored the preparation of PtxRu1-x-NiTiO3 hybrid electrocatalysts for the application of methanol oxidization. The XRD and Raman analysis of PtxRu1-x-NiTiO3 confirmed the rhombohedral crystal structure of NiTiO3 and cubic-structured Pt(Ru) nanoparticles. TEM analysis signifies that Pt(Ru) nanoparticles is decorated on the surface of the NiTiO3. The mean size of the Pt(Ru) nanoparticles calculated from the TEM profile is around 2 nm which corroborates with the crystallite size estimated from XRD. The XPS analysis confirms the presence of metallic Pt along with its oxidized components (Pt2+ and Pt4+). The cyclic voltammetry analysis evidence that Pt0.5Ru0.5-NiTiO3 has shown better activity in methanol oxidation compared with the other compositions of PtxRu1−x-NiTiO3 along with the maximum current density of 65.41 mA cm−2 with less carbon poisoning. Chronoamperometry and polarization studies represent the stability and electrochemical activity of the Pt0.5Ru0.5-NiTiO3 electrocatalysts towards methanol oxidation. Based on the research carried out in this work, it is concluded that the PtxRu1−x-NiTiO3 would be a promising candidate as an electrocatalyst for methanol oxidation in direct methanol fuel cells.

Overview of the catalytic properties of bulk unsupported and supported group 4–5-6 oxides

The number of active sites (Ns), surface chemistry (redox, acid, base) and TOF values were compared for bulk one component oxides, bulk mixed metal oxides and supported metal oxides. The number of active sites was based on CH3OH chemisorption. The surface chemistry was based on CH3OH-TPSR and steady state CH3OH oxidation. The specific TOF values were based on the steady state methanol oxidation activity values and Ns values. The Ns values were found to depend on the catalyst morphology (isotropic > anisotropic). The surface chemistry was found to dramatically depend on the specific metal oxide element. For supported bulk mixed metal molybdates, the surfaces were found to be dominated by segregation of MoOx and, consequently, the surface chemistry and TOFredox values were dominated by the characteristics of the bulk one component MoO3. Similarly, for the supported molybdenum oxide catalysts, the surface is dominated by the surface MoOx sites that dictate the surface chemistry and TOFredox values that reflect the surface chemistry and TOFredox of the bulk one component MoO3. Thus, it is possible to predict the surface chemistry and TOF values from knowledge of the surface composition of mixed oxides and the surface chemistry and TOF values of the bulk one component oxides. This conclusion should also hold for other types of mixed oxides such as polyoxometalates (POMs) and supported MOx/silicates and MOx/zeolite catalyst systems.

Formation of Pt-NiO/rGO triphasic junction with significantly enhanced electrocatalytic activity for methanol oxidation

Pt-based nanocomposites such as Pt- metal oxide framework have been widely used as electro catalysts for direct methanol fuel cell (DMFC) due to their significant catalytic activity and stability. In this study, Pt-NiO encapsulated with reduced graphene oxide (rGO) nanosheet is prepared by making a thin film of GO over deposited Pt-NiO on Indium tin oxide support, followed by facile electrochemical reduction technique. As-synthesized materials are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electrocatalytic performance is investigated by cyclic voltammetry (CV), chronoamperometry and impedance spectroscopy. These results indicate that Pt-NiO/rGO ternary phase catalyst junction exhibits significant CV peak current density (669 mA mg−1 of Pt) which is 2.9 and 1.7 times higher than that of fabricated Pt-NiO and commercial Pt(10 mass% )-XC72 respectively. The electrode also possesses excellent stable catalytic activity than Pt-NiO. The charge transfer conductance of Pt-NiO based electrode is improved 17 times and the electrochemical surface area is increased by ca. 2 times by incorporation of overhead rGO nanosheet. These results imply that Pt-NiO/rGO nanocomposite could be a better electrocatalyst for DMFCs application.

ELECTROCATALYSIS OF COBALT DOPED CeO2/rGO NANOCOMPOSITE FOR OXIDATION OF METHANOL AND FORMIC ACID

In this study,a novel cobalt-doped cerium oxide (CeO2)on reduced graphene oxide (rGO) substrate was successfully prepared through a hydrothermal method.The comprehensive characterization of the synthesized nanocomposite involved X-ray diffraction studies (XRD),Raman spectrum analysis,High Resolution Transmission Electron microscopy (HRTEM), and Field Emission Electron Microscopy (FE-SEM).The effective surface area of CeO2/rGO and Co-CeO2/rGO was determined using the Randles-Sevecik equation,revealing values of 4.02X10-5 cm2 and 6.35X10-5 cm 2 ,respectively.Cyclic Voltammetry (CV) was employed to investigate the electrochemical reversibility behavior, demonstrating promising results for Co-CeO2/rGO nanocomposite.Electrochemical impedance spectroscopy(EIS) further highlighted low charge transfer resistance (Rct) and enhanced double-layer capacitance (Cdl).Notably, the synthesized nanocomposite exhibited excellent electrocatalytic activity for methanol and formic acid oxidation in an acidic medium. Overall, this work provides valuable insights into the synthesis characterization, and electrochemical performance of Co-CeO2/rGO nanocomposite, showcasing their potential applications in energy- related processes.

Scalable production of bifunctional ordered PtFe alloy electrocatalysts for efficient methanol oxidation and hydrogen evolution

Sub-5 nm sized ordered PtFe alloys encapsulated with thin N-doped carbon (NC) shells exhibit remarkable electrochemical performance both toward methanol oxidation and hydrogen evolution reactions.

Evolution of High-Index Facets Pt Nanocrystals Induced by N-Defective Sites in the Integrated Electrode for Enhanced Methanol Oxidation.

Highly efficient and durable Pt electrocatalysts are the key to boost the performance of fuel cells. The high-index facets (HIF) Pt nanocrystals are regarded as excellent catalytic activity and stability catalysts. However, nucleation, growth and evolution of high-index facets Pt nanocrystals induced by defective sites is still a challenge. In this work, tetrahexahedron (THH) and hexactahedron (HOH) Pt nanocrystals are synthesized, which are loaded on the nitrogen-doped reduced graphene oxide (N-rGO) support of the integrated electrodes by the square wave pulse method. Experimental investigations and density functional theory (DFT) calculations are conducted to analyze the growth and evolution mechanism of HIF Pt nanocrystals on the graphene-derived carbon supports. It shows that the H adsorption on the N-rGO/CFP support can induce evolution of Pt nanocrystals. Moreover, the N-defective sites on the surface of N-rGO can lead to a slower growth of Pt nanocrystals than that on the surface of reduced graphene oxide (rGO). Pt/N-rGO/CFP (20min) shows the highest specific activity in methanol oxidation, which is 1.5 times higher than that of commercial Pt/C. This research paves the way on the design and synthesis of HIF Pt nanocrystal using graphene-derived carbon materials as substrates in the future.

Electro-Oxidation Reaction of Methanol over La2-xSrxNi1-y(Mn/Fe/Co)yO4+δ Ruddlesden-Popper Oxides.

Solution combustion-synthesized Ruddlesden-Popper oxides La1.4Sr0.6Ni0.9(Mn/Fe/Co)0.1O4+δ were explored for the methanol electro-oxidation reaction. With optimal doping of Sr2+ in the A site and Co2+ in the B site, Ni3+ with t2g6 configuration in La1.4Sr0.6Ni0.9Co0.1O4+δ exhibited a tetragonal distortion with compression in axial bonds and elongation in equatorial bonds. This structural modification fostered an augmented overlap of orbitals with axial O 2p orbitals, leading to a heightened density of states at the Fermi level. Consequently, this facilitated not only elevated electrical conductivity but also a noteworthy reduction in the charge transfer resistance. These effects collectively contributed to the exceptional methanol oxidation activity of La1.4Sr0.6Ni0.9Co0.1O4+δ, as evidenced by an impressive current density of 21.4 mA cm-2 and retention of 95% of initial current density even after 10 h of prolonged reaction. The presence of Ni3+ further played a pivotal role in the creation of NiOOH, a crucial intermediate species, facilitated by the presence of surface oxygen vacancies. These factors synergistically enabled efficient methanol oxidation. In summary, our present study not only yields substantial insights but also paves the way for a novel avenue to fine-tune the activity of Ruddlesden-Popper oxides for the successful electro-oxidation of methanol.

Enhancing methanol oxidation electrocatalysis by Pt/Mo2CTx-rGO ternary hybrid catalyst

Here we report a ternary hybrid catalyst, Pt/Mo2CTx-rGO, for the electrocatalysis of methanol oxidation in direct methanol fuel cells. Two-dimensional Mo2CTx MXene was used to modify reduced graphene oxide (rGO) to obtain a hybrid of Mo2CTx-rGO. Thereafter, ultrafine Pt nanoparticles were dispersed on the hybrid to make a ternary catalyst of Pt/Mo2CTx-rGO. The electrochemical performance of the catalyst was evaluated in 1 M H2SO4 and 2 M methanol electrolyte as a target analyte. Compared with commercial Pt/C, Pt/Mo2CTx-rGO demonstrated 1.5 times larger electrochemically active surface area, 1.9 times higher mass activity, and 33.6 % longer durability. This is because of the strong electronic interaction between Pt and Mo2CTx as well as the large surface area of rGO. This work reports a novel electrocatalyst with high activity and long durability for methanol oxidation, and explore a novel application of Mo2CTx MXene.

One-Pot template free synthesis of bimetallic alloy Pt-M/C (M = Fe, Co & Cu) with improved activity for electrocatalytic oxidation of methanol

We prepared a simple, one-step synthesis of Pt-M (M = Co, Cu & Fe)/C supported on Vulcan-XC-72 carbon using the polyol reduction method. The morphology, structure and elemental composition of the prepared catalysts were confirmed by transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). Electrochemical characterization including electrochemical impedance, cyclic voltammetry and chronoamperometry were studied to compare the electrochemical activity of the as-prepared catalyst with standard 20 wt % Pt/C. From transmission electron microscopy studies, the estimated average particle size for PtFe/C, PtCo/C and PtCu/C were 16, 12 and 10 nm respectively. In cyclic voltammetry studies, the PtFe/C catalyst exhibited the maximum current density for electrooxidation of methanol (14.88 mA cm−2), compared to PtCu/C (9.96 mA cm−2), PtCo/C (4.66 mA cm−2) and Pt/C (2.34 mA cm−2). Also, the negative sweep onset potential and greater If/Ib ratio verified the enhanced activity of the PtFe/C catalyst. The stability of the catalyst was studied using chronoamperometric methods, which reveals the slow decay of the prepared catalyst and higher current density for initial and final time intervals. Impedance studies confirm that the PtFe/C catalyst exhibits the smallest semicircle, suggesting a significantly higher electrooxidation rate in comparison to the other catalysts. The electrocatalytic activity of the prepared catalyst follows the order: PtFe/C > PtCu/C > PtCo/C > Pt/C.

One-Dimensional, First-Row Transition Metal, Core-Shell Architectures as Multifunctional Electrocatalysts in Alkaline and Acidic Conditions

The development of practical electrocatalysts for fuel cells, electrochemical sensors, and batteries requires nanostructured architectures with high catalytic activity and good long-term durability. It is also essential that they have very low or even no platinum content. There has also been a recent emphasis on the importance of designing multifunctional catalysts with the ability to efficiently catalyze a wide-range of electrochemical reactions in both acidic and alkaline media. In light of these requirements, we have developed a solution-based synthetic method to prepare core-shell nanowires consisting of inexpensive and abundant first-row transition metals coated with precious metal shells. The core-shell motif enables a substantial quantity of platinum to be removed from the catalytically inactive core of the material, while also resulting in the ability to tune the activity of platinum through electronic and structural interactions between the two metals. The as-synthesized core-shell nanowires have a complex surface structure that brings together metal oxide and precious metal active sites that are active toward OER and result in a significant reduction in the overpotential for OER when compared with pure Pt and Co nanowires. In addition, we have developed an electrochemical process that selectively removes the metal oxide from the surface of the nanowires enabling the catalysts to be activated toward SOM oxidation in acidic media and ORR in alkaline media. For example, the activated core-shell nanowires display a 1.5-fold and a 4-fold increase in the specific activity and mass activity of methanol oxidation, respectively, relative to a pure platinum nanowire.

Highly Dispersed PdNi Nanoparticles on an Oxygen-Functionalized Activated Carbon with Extraordinary Electrocatalytic Activity for Methanol Oxidation

Highly Dispersed PdNi Nanoparticles on an Oxygen-Functionalized Activated Carbon with Extraordinary Electrocatalytic Activity for Methanol Oxidation

Pt3Cu alloy anchored on nanoporous WO3 with high activity and stability in methanol oxidation

Designing highly efficient and durable electrode for methanol oxidation reaction (MOR) is crucial to commercializing direct methanol fuel cells (DMFCs). However, traditional Pt/C catalysts usually suffer from CO poisoning, and agglomeration of powder catalyst, which leads to rapid activity degradation. Herein, we have successfully fabricated self-supported Pt3Cu@3DP-WO3/W electrode via a facile and effective synthesis approach by combining anodic oxidation and electrodeposition method. Benefitting from the three dimensional nanoporous of WO3 with more surface area and strong adhesion, and Pt3Cu alloy synergism induced the lattice compressive strain, the Pt3Cu@3DP-WO3/W electrode achieved 2.77-fold and 4.8-fold enhancement in specific activity (2.15 mA cm−2) and mass activity (853 mA·mgPt−1) for MOR relative to Pt/C catalysts, respectively. Moreover, both the experiments and theoretical calculations revealed that the doping of Cu element weakened the chemisorption of CO-like intermediates by lowering the Pt d-band center through compressive lattice strain, which resulting in excellent catalytic stability. This binder-free self-supported electrode is a viable alternative for commercial application of DMFCs.

Electro-oxidation Reaction of Methanol over Reducible Ce1-x-yNixSryO2-δ: A Mechanistic Probe of Participation of Lattice Oxygen.

Methanol oxidation reaction crucially depends on the formation of -OOH species over the catalyst's surface. Ni-based catalysts are by far the choice of materials, where the redox couple of Ni2+/Ni3+ facilitates the formation of -OOH species by surface reconstructions. However, it is challenging to oxidize Ni2+ as it generates charge-transfer orbitals near the Fermi energy level. One possible solution is to substitute Ni2+ with a reducible oxide support, which will not only facilitate the Ni2+ → Ni3+ oxidation but also adsorb oxygenated species like -OOH at a lower potential owing to its oxophilicity. This work shows with the help of structural and surface studies that the reducible CeO2 support in Ni and Sr co-doped Ce1-x-yNixSryO2-δ solid solution can easily facilitate Ni2+ → Ni3+ oxidation as well as evolution of lattice oxygen during the methanol oxidation reaction. While the Ni3+ species helped in formation of -OOH surface intermediates, the evolved lattice oxygen eased the CO oxidation process in order to bring out the better CO-tolerant methanol oxidation activity over Ce1-x-yNixSryO2-δ. The study shows the unique importance of the electronic interactions between the active site and support and involvement of lattice oxygen in the methanol oxidation reaction.