Electrocatalysts For Methanol Oxidation Reaction Research Articles

Core-shell Pd-P@Pt-Ni nanoparticles with enhanced activity and durability as anode electrocatalyst for methanol oxidation reaction.

Pd–P@Pt–Ni core–shell nanoparticles, which consisted of a Pd–P alloy as a core and Pt–Ni thin layer as a shell, were explored as electrocatalysts for methanol oxidation reaction. The crystallographic information and the electronic properties were fully investigated by X-ray diffraction and X-ray photoelectron spectroscopy. In the methanol electrooxidation reaction, the particles showed high catalytic activity and strong resistance to the poisoning carbonaceous species in comparison with those of commercial Pt/C and the as-prepared Pt/C catalysts. The excellent durability was demonstrated by electrochemically active surface area loss and chronoamperometric measurements. These results would be due to the enhanced catalytic properties of Pt by the double synergistic effects from the core part and the nickel species in the shell part.

Efficient Methanol Electrooxidation Catalyzed by Potentiostatically Grown Cu–O/OH(Ni) Nanowires: Role of Inherent Ni Impurity

Complete electrooxidation of methanol in alkaline conditions is catalyzed efficiently by 3d transition metal-based oxides and hydroxides with no issues of mass-transport limitations. Among them, the oxides and hydroxides of Cu prepared using various methods were said to be exceptional. In this work, the methanol oxidation reaction (MOR) activity of such a copper oxide/hydroxide catalyst is advanced by making use of the three-dimensional (3D) configuration of the Cu foam substrate and inherent Ni impurity present in it. The 3D configuration of the Cu foam substrate enabled a larger active surface area per unit geometrical area. The MOR current densities 110 and 310 mA cm–2 at 0.60 and 0.75 V vs Hg/HgO, respectively, testify the outstanding MOR activity of Cu–O/OH nanowires with Ni impurity (Cu–O/OH(Ni)). Excellent chronoamperometric stability at 0.55 V vs Hg/HgO and relatively lower activation energy at all potentials in the catalytic turnover region further ascertain the superiority of Cu–O/OH(Ni). Specific activity measurements implied that Cu–O/OH(Ni) benefited from intrinsic activity enhancement by the presence of inherent Ni impurity. This work, thus, reveals a facile way of enhancing the MOR activity of Cu-based MOR electrocatalysts.

Synthesis of defect-impressive boron graphene as a remarkable electrocatalyst for methanol oxidation reaction

Boron defect graphene (BdG) of a forked tree like structure is successfully fabricated using a vacuum-thermal annealing of boric acid at 900 oC under the argon gas stream. It's thoroughly characterized together with the reduced graphene oxide and graphene oxide arrangements by XRD, TEM, Raman, N 2 adsorption, XPS and electronic conductivity. BdG that exhibits high average surface area, high p-type conductivity and appreciable porosity delivers an exceptional methanol oxidation reactivity than RGO and GO and surprisingly exceeds that of the commercial Pt/C catalysts. The BdG electro-catalyst indicates higher current density comprised of 21.0 mA cm−2 than RGO (4 times) and Pt/C (2 times) electrodes in an alkaline medium. The reaction kinetics, charges transfer resistance, and stability are thoroughly determined. The obtained results revealed that the defect sites launched by boron insertion include the existence of B–O and B2CO beside the porosity are recognized as highly active sites for methanol oxidation. Based on the obtained results, a proposed mechanism has been designed. The CO tolerance of the BdG indicates lower onset potential and peak potential compared to the Pt/C electrode and rather reflects the role of the former defects on facilitating the methanol oxidation.

ZIF-8@ZIF-67-Derived Co Embedded into Nitrogen-Doped Carbon Nanotube Hollow Porous Carbon Supported Pt as an Efficient Electrocatalyst for Methanol Oxidation.

It is of prime importance to develop anode electrocatalysts for direct methanol fuel cells (DMFCs) with good performance, which is critical for their commercial applications. Metal-organic framework (MOF)-derived carbon materials are extensively developed as supports of catalysts. Herein, Co embedded nitrogen-doped carbon nanotube hollow porous carbon (Co-NCNT-HPC) derived from MOFs have been fabricated, which were synthesized by pyrolyzing at an optimized temperature of 800 °C using ZIF-8@ZIF-67 as a precursor. The presence of ZIF-8@ZIF-67 ensures the doping of nitrogen and the large specific surface area of the support materials at high temperatures. A Pt/Co-NCNT-HPC800 sample, which was synthesized using Co-NCNT-HPC800 as a support, showed an enhanced mass activity of 416.2 mA mg−1Pt for methanol oxidation reaction (MOR), and the onset potential of COad oxidation of 0.51 V, which shifted negatively about 0.13 V compared with Pt/C (20%). Moreover, the Pt/Co-NCNT-HPC800 sample exhibits high stability. This work provides a facile strategy for MOF-derived carbon materials to construct advanced electrocatalysts for MOR.

Platinum modified nickel nitride catalyst on carbon nanotubes for energy conversion in alkaline medium

Designing and exploiting low loading Platinum (Pt) based electrocatalysts are critical in the electrochemical reaction because of its high-efficiency in alkaline conditions for energy conversion. Herein, electrocatalysts of NiNx@Pt nanoparticles deposited on surface of functionalized carbon nanotubes (CNTs) have been prepared by simple sintering and reduction reaction, and then applied as electrocatalyst for methanol oxidation reaction (MOR), oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Under alkaline medium, a current density of 610.4 mA mg−1Pt for MOR is demonstrated which is 1.35 times higher than that of commercial 20 wt% Pt/C (451.2 mA mg−1Pt) catalysts. Besides, the NiNx@Pt/CNT electrocatalyst exhibits more excellent ORR electrocatalytic activity with an onset potential of 0.986 V and half-wave potential of 0.862 V, and an overpotential of 530 mV and low potential gap of 0.89 V for OER. The deposited NiNx nanoparticles not only serve as the center of catalyst with favorable electronic structure, but also effectively prompt the electron transport from Pt nanoparticles to carbon nanotubes. Overall, extraordinary electrocatalysis activity is presented for the versatile NiNx@Pt/CNT electrocatalyst for multiple electrochemical reactions.

Carbon monoxide-resistant copper-cobalt nanocrystal@ nitrogen-doped carbon electrocatalysts for methanol oxidation reaction

The performance of direct methanol fuel cells (DMFC) mainly depends on the activity and stability of the noble-metal-based anode catalysts for methanol oxidation reaction (MOR), whose broad application is limited by the scarcity of noble metals and their susceptibility to carbon monoxide poisoning. Many efforts have been devoted to the developing of non-noble metal based MOR catalysts. Previous studies have shown that the catalytic properties of noble-metal catalysts can be modified by alloying in nanomaterials. However, non-noble metal-based nanocrystals are rarely studied as electrocatalysts, because of their high susceptibility to air oxidation. Herein, we report a simple strategy to prepare non-noble metal nanocrystals (Cu-Co nanocrystals), which are stabilized in a nitrogen-doped carbon (N-C) matrix to form Cu-Co@N-C composite. Since Co has a high activity for oxidation reactions, and Cu has a high adsorption capacity for methanol, the Cu-Co nanocrystals should present good MOR activity because of the synergistic effect of Cu and Co. The highly active Cu-Co nanocrystals are embedded in a porous N-C matrix with a large specific surface area (127.3 m2/g), which not only protects the Cu-Co nanocrystals, but also facilitate the mass and charge transfer. Indeed, the optimal Cu-Co@N-C catalyst shows a MOR activity of 171.3 mA/cm2 at 0.6 V vs SCE in alkaline medium, which is higher than most of previously reported Cu and Co-based MOR catalysts. The stability and CO-resistance of the optimal Cu-Co@N-C catalyst are also better than that of Pt/C catalyst, enabling Cu-Co@N-C a promising MOR catalyst for broad application of DMFC.

Hierarchical NiCo2O4 and NiCo2S4 nanomaterials as electrocatalysts for methanol oxidation reaction

In this work, Ni foam supported hierarchical NiCo2O4 nanomaterials are successfully prepared through a hydrothermal process and subsequent calcination process, then the hierarchical NiCo2O4 is converted to hierarchical NiCo2S4 through a hydrothermal anion exchange process. The hierarchical nanomaterials are constructed by a nanorod core and nanoribbons shell. The morphology evolution mechanism of the hierarchical NiCo2O4 is studied by exploratory experiments, the results show that the morphology evolution from nanorod to hierarchical nanostructure undergo a solid–solid process, and the calcination temperature is crucial for the formation of the hierarchical nanostructure. The hierarchical NiCo2O4 and NiCo2S4 nanomaterials are both used as electrocatalysts for methanol oxidation reaction in alkaline electrolyte, and the electrocatalytic activity of the NiCo2S4 is higher than that of the NiCo2O4. Cycling test shows the good stability of the NiCo2S4, and the slight loss of activity during cycling is caused by the surface oxidation of NiCo2S4 in alkaline electrolyte. This work indicate that the hierarchical NiCo2S4 is a promising non-noble metal electrocatalyst for direct methanol fuel cells.

Recent development of Au arched Pt nanomaterials as promising electrocatalysts for methanol oxidation reaction

Recent development of Au arched Pt nanomaterials as promising electrocatalysts for methanol oxidation reaction

A compendium on metal organic framework materials and their derivatives as electrocatalyst for methanol oxidation reaction

• Role of synthesis on surface & morphology of electrocatalytic MOF & MOF derivatives. • Probing the mechanism of MOR over MOF and MOF derived materials. • A critical compendium on MOFs towards MOR with future perspectives. Despite being one of the most buoyant and trailblazing green energy generation technology, the effective applications of direct methanol fuel cell is challenging mostly due to unavailability of suitably efficient, durable and cost effective catalyst for methanol oxidation reaction. The key features those should be rendered in the electrocatalytic materials are: good electrical conductivity, high surface area, mesoporous structure, excellent chemical stability towards acidic and alkaline medium, and acceptable resistivity toward corrosion. In recent years, one such emerging area of electrocatalysts are metal organic frameworks and the corresponding derived composite materials. The object of this review is to provide an impression of recent progresses in the area of metal organic frameworks and their derivatives for methanol oxidation reaction. The review compiles the synthesis strategies of those framework materials and their derivatives that are extensively being used in methanol oxidation reaction. The electrocatalytic reactivity in correlation with the structure and surface properties of the framework materials are addressed in detail.

Pt-based (Zn, Cu) nanodendrites with enhanced catalytic efficiency and durability toward methanol electro-oxidation via trace Ir-doping engineering

Pt-based alloy nanomaterials with nanodendrites (NDs) structures are efficient electrocatalysts for methanol oxidation reaction (MOR), however their durability is greatly limited by the issue of transition metals dissolution. In this work, a facile trace Ir-doping strategy was proposed to fabricate Ir-PtZn and Ir-PtCu alloy NDs catalysts in aqueous medium, which significantly improved the electrocatalytic activity and durability for MOR. The as-prepared Ir-PtZn/Cu NDs catalysts showed distinct dendrites structures with the averaged diameter of 4.1 nm, and trace Ir doping subsequently improved the utilization of Pt atoms and promoted the oxidation efficiency of methanol. The electrochemical characterizations further demonstrated that the obtained Ir-PtZn/Cu NDs possessed enhanced mass activities of nearly 1.23 and 1.28-fold higher than those of undoped PtZn and PtCu, and approximately 2.35 and 2.67-fold higher than that of Pt/C in acid medium. More excitingly, after long-term durability test, the proposed Ir-PtZn and Ir-PtCu NDs still retained about 88.9% and 91.6% of its initial mass activities, which further highlights the key role of Ir-doping in determining catalyst performance. This work suggests that trace Ir-doping engineering could be a promising way to develop advanced electrocatalysts toward MOR for direct methanol fuel cell (DMFC) applications.

Effects of CeO2 pre-calcined at different temperatures on the performance of Pt/CeO2-C electrocatalyst for methanol oxidation reaction

Pt/CeO2-C catalysts with CeO2 pre-calcined at 300–600°C were synthesized by combining hydrothermal calcination and wet impregnation. The effects of the pre-calcined CeO2 on the performance of Pt/CeO2-C catalysts in methanol oxidation were investigated. The Pt/CeO2-C catalysts with pre-calcined CeO2 at 300–600°C showed an average particle size of 2.6–2.9 nm and exhibited better methanol electro-oxidation catalytic activity than the commercial Pt/C catalyst. In specific, the Pt/CeO2-C catalysts with pre-calcined CeO2 at 400°C displayed the highest electrochemical surface area value of 68.14 m2·g−1 and If/Ib ratio (the ratio of the forward scanning peak current density (If) and the backward scanning peak current density (Ib)) of 1.26, which are considerably larger than those (53.23 m2·g−1 and 0.79, respectively) of the commercial Pt/C catalyst, implying greatly enhanced CO tolerance.

Zinc-Coordination Polymer-Derived Porous Carbon-Supported Stable PtM Electrocatalysts for Methanol Oxidation Reaction.

Porous carbon (PC) is obtained by carbonizing a zinc-coordination polymer (MOF-5) at 950 °C and PtM (M = Fe, Co, Ni, Cu, Zn) nanoparticles (NPs), which are deposited on PC using the polyol method. Structural and morphological characterizations of the synthesized materials are carried out by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM), and the porosity was determined using a N2 adsorption/desorption technique. The results revealed that PtM NPs are alloyed in the fcc phase and are well dispersed on the surface of PC. The electrochemical results show that PtM/PC 950 catalysts have higher methanol oxidation reaction (MOR) performances than commercial Pt/C (20%) catalysts. After 3000 s of chronoamperometry (CA) test, the MOR performances decreased in the order of Pt1Cu1/PC 950 > Pt1Ni1/PC 950 > Pt1Fe1/PC 950 > Pt1Zn1/PC 950 > Pt1Co1/PC 950. The high MOR activities of the synthesized catalysts are attributed to the effect of M on methanol dissociative chemisorption and improved tolerance of Pt against CO poisoning. The high specific surface area and porosity of the carbon support have an additional effect in boosting the MOR activities. Screening of the first row transition metals (d5+n, n = 1, 2, 3, 4, 5) alloyed with Pt binary catalysts for MOR shows that Pt with d8 (Ni) and d9 (Cu) transition metals, in equivalent atomic ratios, are good anode catalysts for alcohol fuel cells.

Pt-Ru/polyaniline/carbon nanotube composites with three-layer tubular structure for efficient methanol oxidation

Developing anode catalyst with highly active and CO tolerance of direct methanol fuel cells is of prime importance. In this work, the polyaniline/carbon nanotube composites were fabricated via in situ electrochemical method. The Pt–Ru alloy nanoclusters were well-distributed on polyaniline/carbon nanotubes supporting materials by co-electrodeposition method. SEM, HRTEM and XPS were employed to investigate the surface features of composites. The results indicated that Pt-Ru/polyaniline/carbon nanotubes composites were formed three-layer tubular structure. The Pt9.8Ru1/polyaniline/carbon nanotubes catalyst displayed good performance along with the lower peak potential of forward-scanning methanol oxidation, longer-term stability and higher current density compared to Pt/C, Pt-Ru/carbon nanotube composites and other Pt-Ru/polyaniline/carbon nanotube composites. The current density of the Pt9.8Ru1/PANI/CNTs catalyst for methanol oxidation was 8.9 folds higher than that for Pt/C and 2.4 folds higher for Pt9.8Ru1/CNTs catalyst, which indicated that this catalyst had a high number of active sites and surface Ru sites could effectively facilitate the removal of COad. Our data showed that the prepared Pt-Ru/polyaniline/carbon nanotubes composites are potential candidate as bimetallic electro-catalysts for methanol oxidation reaction.

Nanocluster PtNiP supported on graphene as an efficient electrocatalyst for methanol oxidation reaction

In this study, phosphorus doped graphene supported PtNiP nanocluster electrocatalyst (PtNiP/P-graphene) was successfully prepared via a simple hypophosphite-assisted co-reduction method. The improved anchoring force and increased anchoring sites of graphene support result from phosphorus doping as well as size-confined growth effect of NaH2PO2 leads to uniform dispersion of ultrafine PtNiP nanoclusters. Doped P also promotes the removal of CO-like intermediate by adjusting Pt electronic structure combining with alloyed Ni via electronic effects. As a result, the as-prepared PtNiP/P-graphene catalyst with more exposed active sites and optimized electronic structure of Pt alloy shows excellent electrocatalytic performances for methanol oxidation reaction (MOR) both in activity and durability in an acidic medium.

Porous layered cobalt nanocrystal/nitrogen-doped carbon composites as efficient and CO-resistant electrocatalysts for methanol oxidation reaction

The development of active, stable and poison-resistant electrocatalysts for methanol oxidation reaction (MOR) has become a key challenge to improve the performance of direct methanol fuel cells (DMFCs). Herein, we report a simple strategy to prepare cobalt nanoscrystal/nitrogen-doped carbon (Co/N-C) composites as efficient and carbon monoxide (CO) resistant electrocatalysts for MOR. The Co/N-C composites are synthesized by the pyrolysis of porous CoCl2-polyaniline hydrogels. While CoCl2 is reduced to Co nanocrystals as active electrocatalyst for MOR, the polyaniline hydrogel is pyrolyzed to porous layered N-doped carbon that immobilize and protect Co nanocrystals, and also facilitate the mass and charge transfer through the electrolyte and electrode. After systematically exploring the preparation conditions of Co/N-C composites, we have found the optimal Co/N-C-1-500 (pyrolyzed at 500 °C) can achieve a high current density of 231 mA∙cm−2 at 0.8 V vs SCE for MOR in alkaline media. Meanwhile, the Co/N-C-1-500 catalyst presents a good durability and a high resistance to CO poisoning (93.5% retention of MOR activity), superior to the performance of Pt/C catalysts. With its high activity, good stability and superior resistance to CO poisoning, Co/N-C-1-500 is promising as a low-cost and efficient anode catalyst for DMFCs.

Ultrafine Rh-Decorated 3D Porous Boron and Nitrogen Dual-Doped Graphene Architecture as an Efficient Electrocatalyst for Methanol Oxidation Reaction

The development and utilization of high-performance Pt-alternative anode materials with acceptable costs have recently become a hot issue in the fuel cell field. Here, we put forward a convenient a...

PtPdCu cubic nanoframes as electrocatalysts for methanol oxidation reaction

PtPdCu cubic nanoframes with unique open architecture exhibit excellent electrocatalytic performances toward methanol electrooxidation.

Lanthanide electronic perturbation in Pt–Ln (La, Ce, Pr and Nd) alloys for enhanced methanol oxidation reaction activity

A series of PtLn alloys have been synthesized to act as efficient electrocatalysts for methanol oxidation reactions, where the electronic perturbations of lanthanide guarantee high electroactivity and long-term durability.

Recent progress in development of efficient electrocatalyst for methanol oxidation reaction in direct methanol fuel cell

The human craving for energy is continually mounting and becoming progressively difficult to Gratify. At present, the world's massive energy demands are chiefly encountered by nonrenewable and benign fossil fuels. However, the development of dynamic energy cradles for a gradually thriving world to lessen fossil fuel reserve depletion and environmental concerns are persistent issues for society at present. The discovery of copious nonconventional resources to fill the gap between energy petition and supply is the extreme obligation of the modern era. A new emergent, clean, and robust alternate of fossil fuels are the fuel cells. Among the different types of fuel cells, direct methanol fuel cells are an outstanding option for light-duty vehicles and portable devices. A critical tactic for striving and sustainable energy sources is the production of highly proficient, economical, and green catalysts for energy storage and conversion devices. Up till now a broad range of research work is available to use Pt and modify Pt-based electrocatalysts to augment the CH3OH oxidation process. Platinum-based nanocubes, nanorods, nanoflower, hybrids of Pt with metal-oxides such as Fe2O3, TiO2, SnO2, MnO, Cu2O, ZnO, and with conducting polymers are extensively utilized in both acidic and basic media. Moreover, Pd-based materials, transition metal-based materials as well as MOF and MOF-derived materials are also the point of interest for researchers nowadays. However, the problem associated with their practical applications is that they can be effectively employed in basic media due to comparative less stability in acidic medium. This review article will deliver a broad vision of the current progress of the MOR process concerning noble metals, transition metals, and MOF-based materials.

Au nanowires with high aspect ratio and atomic shell of Pt-Ru alloy for enhanced methanol oxidation reaction

The methanol oxidation reaction (MOR) is the limiting half-reaction in direct methanol fuel cell (DMFC). Although Pt is the most active single-metal electrocatalyst for MOR, it is hampered by high cost and CO poisoning. Constructing a Pt or Ru monolayer on a second metal substrate by means of galvanic replacement of underpotentially deposited (UPD) Cu monolayer has been shown as an efficient catalyst design strategy for the electrocatalysis of MOR because of the presumed 100% utilization of atoms and resistance to CO poisoning. Herein, we prepared one-dimensional surface-alloyed electrocatalyst from predominantly (111) faceted Au nanowires with high aspect ratio as the substrate of under-potential deposition. The electrocatalyst comprises a core of the Au nanowire and a shell of catalytically active Pt coated by Ru. Coverage-dependent electro-catalytic activity and stability is demonstrated on the Pt/Ru submonolayers on Au wires for MOR. Among all these catalysts, Au@PtML@RuML exhibits the best electrocatalytic activity and poisoning tolerance to CO. This presents a viable method for the rational catalyst design for achieving high noble-metal utilization efficiency and high catalytic performance.