Electrocatalytic Oxidation Of Methanol Research Articles

Palladium nanocrystals immobilized on boron and nitrogen codoped mesoporous carbon spheres as efficient methanol oxidation electrocatalysts

The development of cost-effective and high-performance electrocatalysts is crucial for the widespread application of direct methanol fuel cell. Herein, a convenient and robust method is developed to the controllable fabrication of Pd nanocrystals in situ immobilized on boron and nitrogen codoped mesoporous carbon spheres (Pd/BNMCS) as anode catalysts for the methanol oxidation reaction. The as-derived Pd/BNMCS hybrids are equipped with a series of useful structural features, such as large specific surface area, abundant mesoporous channels, presence of plentiful B and N atoms, well-dispersive Pd nanoparticles, and good electrical conductivity. As a consequence, the optimized Pd/BNMCS catalyst demonstrates superior electrocatalytic methanol oxidation properties in terms of a large electrochemically active surface area, high mass/specific activities, and reliable long-term stability, which are significantly better than those of traditional carbon black and undoped mesoporous carbon sphere supported Pd catalysts. This study highlights the potential of heteroatom codoped mesoporous carbon matrixes in the construction of advanced noble metal electrocatalysts for practical fuel cell applications.

Growth Modulation of High-Entropy Alloys for Electrocatalytic Methanol Oxidation Reaction.

High-entropy alloy (HEA) electrocatalysts have exhibited remarkable catalytic performance because of their synergistic interactions among multiple metals. However, the growth mechanism of HEAs remains elusive, primarily due to the constraints imposed by the current synthesis methodologies for HEAs. In this work, an innovative electrodeposition method was developed to fabricate Pt-based nanocomposites (Pt1Bi2Co1Cu1Ni1/CC), comprising HEA nanosheets and carbon cloths (CCs). The reaction system could be effectively monitored by taking samples out from the system during the reaction process, facilitating in-depth insight into the growth mechanism underlying the material formation. In particular, Pt1Bi2Co1Cu1Ni1/CC nanocomposites show superior methanol oxidation reaction (MOR) performance (mass activity up to 5.02 A mgPt-1). Upon structural analysis, the d-band center of Pt1Bi2Co1Cu1Ni1/CC is lower in comparison with that of Pt1Bi2/CC and Pt/CC, demonstrating the formation of a rich-electron structure. Both the uniformity of HEAs and the carbon-supported effect could provide additional active sites. These findings suggest that the strong electronic interaction within HEAs and additional active sites can effectively modulate the catalytic structure of Pt, which benefits the enhanced CO tolerance and MOR performance.

Construction of Multiphase Concave Tetrahedral PdInMo Nanocatalyst for Enhanced Alcohol Oxidation

AbstractHeterogeneous palladium‐based catalysts show excellent catalytic properties for electrocatalytic oxidation of alcohols, but the construction of such heterogeneous catalysts is a challenge. Here, a multiphase tetrahedral PdInMo nanocatalyst is prepared by a one‐pot reaction method. And the multiphase tetrahedral PdInMo nanocatalyst consists of a face‐centered cubic structure and an intermetallic structure. Due to the oxygen affinity of indium and molybdenum atoms, the interface defects of internal multiphase structure, and intermetallic structure, the multiphase concave tetrahedral PdInMo nanocatalyst shows enhanced catalytic efficiency in the electrocatalytic oxidation reaction of methanol and ethanol. Compared with commercial Pd/C catalysts, PdIn0.117Mo0.037 nanocatalyst has the best mass activity and specific activity. In electrocatalysis of methanol oxidation, the mass activity (2205.57 mA mgPd−1) and specific activity (6.67 mA cm−2) are 4.81 and 3.40 times than that of a commercial Pd/C nanocatalyst (458.5 mA mgPd−1, 1.96 mA cm−2), respectively. In the electrocatalysis of ethanol oxidation, the mass activity (2668.49 mA mgPd−1) and specific activity (8.11 mA cm−2) are 4.06 and 3.14 times than that of the commercial Pd/C nanocatalyst (655.83 mA mgPd−1, 2.58 mA cm−2), respectively. This study provides a reference for the design of highly efficient palladium catalysts for alcohol oxidation.

On the Design of the Metal–Support Interface in Methanol Electrocatalytic Oxidation

On the Design of the Metal–Support Interface in Methanol Electrocatalytic Oxidation

Constructing hollow cobalt sulfide nanocages strung by manganese molybdate nanorods for high-efficiency supercapacitors and electrocatalytic methanol oxidation

Constructing core-shell heterostuctures with rationally designed nanoarchitectures and components is a promising strategy to pursuit high-efficiency energy storage and conversion in supercapacitors (SCs) and direct methanol fuel cells (DMFCs). Herein, a multi-dimensional MnMoO4@CoS core-shell heterostructure is designed and synthesized by stringing metal-organic framework-derived hollow CoS nanocages with MnMoO4 nanorods. Such heterostructure provides more electroactive sites and enhanced structural stability. Theory calculations unveil that the work function difference between MnMoO4 and CoS induces the charge redistribution and modulate interfacial electronic configuration in the MnMoO4/CoS heterojunction. Meanwhile, a interfacial built-in electrical field is established, enhancing interfacial charge transfer efficiency and promoting the surface adsorption of electrolyte ions. By integrating all these advantages, the MnMoO4@CoS electrode demonstrates enhanced rate capacities (933 C g−1 at 1 A g−1 and 623 C g−1 at 10 A g−1) and cycling durability (90.3 % capacity retention after 10,000 cycles) compared to bare MnMoO4 and CoS electrodes. Moreover, the MnMoO4@CoS electrode exhibits an appreciable electrocatalytic performance for methanol oxidation, with a current density of 294.8 mA cm−2 at 10 mV s−1 and 96.6 % current retention after 10,000 s. Our work offers a fundamental guideline for designing and engineering core-shell heterostructures with desirable electrochemical performance for SCs and DMFCs.

Palladium nanoparticles incorporated biogenic modified graphitic carbon nitride as an electrocatalyst for methanol oxidation reaction

This research explores palladium (Pd) nanoparticles supported on graphitic carbonitride (g-C3N4) as a cost-effective and CO tolerant catalyst towards electrocatalytic methanol oxidation reaction (MOR). The study delves into the green synthesis strategy, employing phytochemicals as reducing, capping and stabilizing agents. This approach aligns with environmentally friendly practices, steering away from hazardous chemicals and solvents commonly used in traditional synthesis methods. The synthesis involves the dispersion of Pd nanoparticles supported on graphitic carbon nitride (g-C3N4) modified by banana leaf extract [PdNPs@g-C3N4-BLE]. The obtained nanocatalyst is characterized using various spectroscopic and microscopic techniques. Further, the synthesized PdNPs@g-C3N4-BLE is utilized as electrocatalyst for methanol oxidation reaction (MOR) in basic medium (1 M KOH). PdNPs@g-C3N4-BLE shows satisfactory activity towards MOR with an onset potential of 0.834 V and current density of 6.795 mA/cm2 at 1.0 V.

Electrocatalytic methanol oxidation by Au nanoparticles decorated nickel tungstate/oxide nanocomplexes

The methanol oxidation reaction (MOR) serves as a critical determinant of the energy conversion efficiency within direct methanol fuel cells (DMFC). Consequently, the development of cost-effective and efficient electrocatalysts is paramount for enhancing energy conversion efficiency associated with MOR. The nanomaterials with diverse metal atomic molar ratio of (Ni:W) were synthesized via hydrothermal method for the immobilization of Au nanoparticles (Au NPs) onto the sample surface. The crystal structure of nanocomposites was confirmed through X-ray diffraction (XRD), and transmission electron microscopy (TEM) images depicted a specific surface topography. The catalytic performance of the synthesized catalysts in the MOR was assessed through electrochemical analysis. Notably, catalyst with the Ni:W atomic ratio of 2:1, displayed superior electrocatalytic performance when compared to catalysts possessing other different metal ratios. Moreover, chronoamperometry tests conducted over 7200 s and Tafel slope analysis demonstrated the enduring activity and strong resistance to toxicity of the synthesized catalysts. These results highlight the potential of nickel-tungstate bimetallic oxide as an exceptionally efficient catalyst in the field of electrocatalysis.

Modulating the electronic structure of PdCoP nanonetworks alloy for efficient electro-catalysis of methanol oxidation

Modulating the d-orbital electronic structure of active metals by doping heteroatoms is efficient for the electro-catalysis of methanol oxidation reaction (MOR). However, precise doping hybrid atoms into the lattices of alloy catalysts remains challenging. Herein, the selected doping of electron-rich P atoms at the active site of Pd was achieved by hydrothermal reduction. We found that P atoms prefer to bond Pd atoms, thus tuning the electronic structure of active sites in PdCoP alloy. Consequently, the tailored PdCoP catalyst exhibited remarkable mass activity of 2.13 A mgPd−1 towards MOR, which surpasses most reported Pd-based alloy nanocatalysts. Theoretical calculations revealed that the tailored d-band center of Pd in PdCoP catalyst exhibited moderate adsorption of CO and OH intermediates, thus maximizing the MOR performance. The current work highlights the fabrication of P-doped Pd-based catalysts for realizing high MOR, which can be further extended to other energy-related applications.

Revealing the Effect of Anion Regulation in NiCo2X4 (X = O, S, Se, Te) on Photoassisted Methanol Electrocatalytic Oxidation.

Designing nonprecious metal anode catalysts for photoassisted direct methanol fuel cells (PDMFCs) remains a challenge. As a semiconductor catalyst with a spinel structure, NiCo2O4 has good methanol catalytic oxidation activity and photocatalytic activity, making it a highly promising anode non-noble metal catalyst for PDMFCs. However, compared with the noble metal catalyst, the photoelectrocatalytic activity remained to be improved. In this report, an anion regulation strategy was adopted to improve the photoassisted methanol electrocatalytic activity. Using a CoNi-Aspartic (CoNi-Asp) nanorod as the precursor, the anion-regulated NiCo2X4 (X = O, S, Se, Te) was prepared by oxidation, sulfuration, selenization, and telluridation reactions. The regulation of anions and their effects on the electronic structure, intermediate product, and photoelectric catalytic performance of NiCo2X4 (X= O, S, Se, Te) was systematically discussed. Photoelectrochemical characterization and adsorption energy of •OH revealing the volcano-like correlation between the anion in NiCo2X4 (X = O, S, Se, Te) and their photoelectrocatalytic performance. The narrowest band gap (2.239 eV), the highest •OH adsorption energy (-3.32 eV), and the highest ratio of Co3+/Co2+ (2.19) ensure the best photoelectric catalytic performance of NiCo2S4, under the visible light irradiation, the photoresponse current density was 1.9 A g-1, the current density at 0.6 V was up to 21.9 A g-1. After 9 h of stability testing, the current retention rate was 80%. This report sheds an idea for the rational design of non-noble anode catalysts for PDMFCs.

Insights into the roles of nitrogen and phosphorus co-doping for efficient methanol electrooxidation

Anchoring Pt onto multi-heteroatom doped carbon materials has been recognized as an effective approach to improve the performance of electrocatalytic methanol oxidation. However, distinct contributions and specific behavior mechanisms of different heteroatoms, notably N and P, the specific behavior mechanisms in synergistically promoting Pt NPs remain elusive. In this work, we construct 1D N and P co-doped carbon nanotube (N, P-CNTs) supports with abundant defect anchors for Pt. The as-prepared Pt/N, P-CNTs exhibit outstanding activity and exceptional stability in methanol oxidation reaction (MOR), achieving high mass activity up to 6481.3 mA mg−1Pt. Moreover, they can retain 90.5 % of their initial current density even after 800 cycles tests. Detailed characterizations and theoretical calculations indicate that the robust strong metal-support interactions (SMSI) effect caused by N doping within the unique N and P co-doped coordination structure controllably regulate the coordination environment of Pt, reduce the d-band center of Pt, thus promoting the adsorption and decomposition of CH3OH. However, P doping weakens the adsorption strength of CO on the Pt active site by sacrificing partial electron transfer, accelerating the oxidative conversion of the CO-like poisoning species (COads). Significantly, the synergistic mechanism of N and P species on the modification of Pt’s electronic structure and its subsequent impact on the electrocatalytic methanol oxidation behaviors on the Pt surface was thoroughly elucidated, providing a constructive route for designing robust MOR electrocatalysts with high MOR activity and durability.

Aqueous Synthesis of Au10Pt1 Nanorods Decorated with MnO2 Nanosheets for the Enhanced Electrocatalytic Oxidation of Methanol.

Developing novel catalysts with high activity and high stability for the methanol oxidation reaction (MOR) is of great importance for the ever-broader applications of methanol fuel cells. Herein, we present a facile technique for synthesizing Au10Pt1@MnO2 catalysts using a wet chemical method and investigate their catalytic performance for the MOR. Notably, the Au10Pt1@MnO2-M composite demonstrated a significantly high peak mass activity of 15.52 A mg(Pt)-1, which is 35.3, 57.5, and 21.9 times greater than those of the Pt/C (0.44 A mg(Pt)-1), Pd/C (0.27 A mg(Pt)-1), and Au10Pt1 (0.71 A mg(Pt)-1) catalysts, respectively. Comparative analysis with commercial Pt/C and Pd/C catalysts, as well as Au10Pt1 HSNRs, revealed that the Au10Pt1@MnO2-M composite exhibited the lowest initial potential, the highest peak current density, and superior CO anti-poisoning capability. The results demonstrate that the introduction of MnO2 nanosheets, with excellent oxidation capability, not only significantly increases the reactive sites, but also promotes the reaction kinetics of the catalyst. Furthermore, the high surface area of the MnO2 nanosheets facilitates charge transfer and induces modifications in the electronic structure of the composite. This research provides a straightforward and effective strategy for the design of efficient electrocatalytic nanostructures for MOR applications.

Ultra-small Pt3Co intermetallic compounds: for efficient electrocatalytic methanol oxidation

Ultra-small Pt3Co intermetallic compounds: for efficient electrocatalytic methanol oxidation

Retraction Note to: Nickel modified ionic liquid/carbon paste electrode for highly efficient electrocatalytic oxidation of methanol in alkaline medium

Retraction Note to: Nickel modified ionic liquid/carbon paste electrode for highly efficient electrocatalytic oxidation of methanol in alkaline medium

Mechanisms of formation and shape control of pentagonal Pd-nanostars and their unique properties in electrocatalytic methanol oxidation and membrane separation of high-purity hydrogen

Membranes on palladium alloy basis with surface modified by nanoparticles with high catalytic activity are useful in deep hydrogen purification and single-stage process of high-purity hydrogen production. This paper reports the development and improvement of methods for synthesis of Pd-based pentatwinned nanoparticles of strictly specified morphology with certain shapes, facets and composition. The competing effect of surfactants and optimization of the halide ions ratio in solution make it possible to direct a particle growth towards formation of pentatwinned Pd-nanostars. Pd–23%Ag coatings synthesized on the surface showed uniquely high peak current density of up to 238 mA cm−2 in alkaline methanol oxidation reaction. This is due to both increased surface area and greater catalytic activity of nanostars’ facets. A record increase in hydrogen permeability of up to 12.5 mmol s−1 m−2 at 100 °C has been achieved for palladium-silver membranes with modified surface. This indicates an acceleration of sorption/desorption stages. The developed method for controlling morphology of nanoscale coatings opens the way to the production of membrane hydrogen filters, which operate at room temperature.

Competitive coordination-induced assembling of Ni-mof/NiFe-ldh heterostructure for enhanced electrocatalytic methanol oxidation

Direct methanol fuel cells (DMFCs) can permit the utilization of noble-metal-free electrocatalysts, which certainly reduces the cost and accelerates their practical implementation. With the exploration of efficient and economical methanol oxidation reaction (MOR) catalysts, Ni-based nanostructures have been recognized as the most promising MOR catalysts in alkaline media. Herein, we construct a novel heterojunction MOR electrocatalyst composed of Ni-based metal-organic framework (Ni-MOF) and NiFe-based layered double hydroxides (LDHs) through a coordination-induced self-assembly strategy. Owing to the synergic effect between Ni and Fe sites, coupled with the effect of hetero-interface, the resultant Ni-MOF/NiFe-LDH composite exhibits remarkable MOR activity in 0.1 M KOH electrolyte with the oxidation current density (32.66 mA cm−2) is 2.65 and 2.44 times higher than that of the primitive NiFe-LDH and Ni-MOF. The excellent stability of the Ni-MOF/NiFe-LDH electrocatalyst has also been confirmed by long-term chronoamperometry (CA) analysis. Our work paves a facile controllable way for fabricating MOF/LDH heterostructure targets on MOR and underlines its potential to boost energy conversion efficiency through the manipulation of synergic components.

Photo-enhanced electrocatalytic methanol oxidation of carbon black-modified Pt and Mo-based oxide for acidic and basic solutions

Pt nanoparticles were electrodeposited on a molybdenum-based oxide (e.g., molybdenum oxide (MoO3) and bismuth molybdate (Bi2MoO6)) modified carbon black (CB) support to study the enhancement of methanol oxidation in acidic and basic solutions with the assistance of visible light illumination. Morphology studies showed that Bi2MoO6 nanoparticles were initially anchored on the CB matrix with round 2.2 nm Pt nanoparticle decoration, resulting in a large extension of the specific active catalytic surface area (SSA) for Pt/Bi2MoO6/CB. It was found that the Pt/Bi2MoO6/CB composite catalyst offered the highest electrocatalytic activity with visible light support, showing 2 (in an acidic solution) and 18 (in a basic solution) times higher reactivity than the electrodeposited Pt/CB. Moreover, the electrocatalytic activity and stability of the prepared catalyst toward methanol oxidation with the aid of visible light were noticeably improved in both acidic and basic solutions, and the oxidation improvement was greatest in basic solutions. Therefore, the improved oxidation performance of the prepared catalysts was mostly a result of the combination of both photocatalytic and electrocatalytic procedures on Pt-based catalysts with metal oxides, resulting in enhanced catalytic activity and stability for the oxidation of methanol and CO under visible light.

New type nanocomposite based on metal-organic frameworks decorated with nickel nanoparticles as a potent electrocatalyst for methanol oxidation in alkaline media

Methanol oxidation reaction (MOR) is used to provide electrical energy via direct methanol fuel cell (DMFC), which requires a practical design of electrocatalysts to accelerate the sluggish MOR. In this study, we successfully fabricated the carbon black nanoparticles/graphite ceramic electrode (CBNPs/GCE) supported metal-organic frameworks (MOFs) and decorated with nickel nanoparticles (NiNPs) as a new type nanocomposite modified electrode (NiNPs/MOFs/CBNPs/GCE) via a chemical and an electrochemical process, respectively. The surface morphology and structure of the synthesized nanocomposite materials and modified electrodes were characterized using field emission scanning electron microscopy, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. Then, the NiNPs/MOFs/CBNPs/GCE was used as a non-platinum electrocatalyst for electrocatalytic oxidation of methanol in alkaline media. The obtained results show the efficient electrocatalytic activity of the NiNPs/MOFs/CBNPs/GCE toward the MOR with high anodic peak current density (Jpa = 34.8 mA cm−2) compared with the other prepared electrocatalysts; MOFs/CCE, NiNPs/CCE, MOFs/CBNPs/GCE, NiNPs/CBNPs/GCE, and NiNPs/MOFs/CCE, due to the synergistic effect of nanocomposite components; NiNPs, MOFs and CBNPs. The prepared electrocatalyst; NiNPs/MOFs/CBNPs/GCE, not only shows a high electrochemically active surface area (ECSA = 2.15 cm2) but also has long-term durability in MOR. In general, it can be said the NiNPs/MOFs/CBNPs/GCE is a promising candidate for application in DMFC.

Constructing Zn-based MOF-MXene nanoarchitectures to stabilize ultrafine Pt nanocrystals with enhanced methanol oxidation performance

Although the development of direct methanol fuel cell technology is regarded as one rational option to against severe energy crises and environmental pollution, the low efficiency and considerable costs of current Pt-based anode catalysts largely impede the broad-scale commercialization. Herein, a convenient bottom-up approach is developed to the spatial construction of ultrafine Pt nanocrystals stabilized on a porous heterojunction matrix built from Zn-based metal organic frameworks and Ti3C2Tx MXene nanolamellas (Pt/ZIF-Ti3C2Tx) through the stepwise solvothermal reactions. The intercalation of metal organic frameworks produces plentiful cavities and channels for the dispersion and immobilization of small-sized Pt nanoparticles, while the incorporation of Ti3C2Tx nanosheets optimizes the Pt electronic structure and ensures a high electron conductivity. As a consequence, the as-acquired Pt/ZIF-Ti3C2Tx nanoarchitectures manifest exceptional electrocatalytic methanol oxidation abilities in terms of a large electrochemically active surface area of 110.5 m2 g−1, a high mass activity of 1900.1 mA mg−1, and preferable long-term stability, all of which are significantly superior to those of conventional Pt/carbon and Pt/unmodified Ti3C2Tx catalysts.

Production of NiCoMo-Supported Ni Foam for Electrocatalytic Oxidation of Methanol: Experimental and RSM Analysis

The Ni-, Co-, and Mo-supported Ni foam (NiF–NiCoMo) was produced via galvanostatic method, and electrooxidation of methanol in alkaline medium was examined. The characterization was achieved using field emission scanning electron microscopy, energy-dispersive X-ray, and X-ray diffraction analysis. The electrochemical behavior was determined via cyclic voltammetry and chronoamperometry analysis. The contribution of each transition metal to electrocatalytic performance of NiF was monitored via mono, binary, and ternary modifications of each transition metal (Ni, Co, and Mo) for several amounts (5, 10, and 15 μg). Experiments were performed to determine the influence of catalyst amounts, methanol concentration, and scan rate parameters. The impacts of independent parameters on methanol electrooxidation were statistically investigated using Design-Expert software. The ability to analyze multiple parameters with a limited number of experimental performances is one of the method’s key benefits. The developed model showed that 9.41 and 14.03 µg catalyst amounts were the appropriate values for NiF–NiMo and NiF–NiCoMo achieving optimal circumstances, respectively.

Heterointerface engineering of rhombic Rh nanosheets confined on MXene for efficient methanol oxidation

Although metallic rhodium (Rh) is regarded as a promising platinum-alternative anode catalyst of direct methanol fuel cell (DMFC), the conventional “particle-to-face” contact model between Rh and matrix largely limits the overall electrocatalytic performance due to their insufficient cooperative effects. Herein, we report a controllable and robust heterointerface engineering strategy for the bottom-up fabrication of rhombic Rh nanosheets in situ confined on Ti3C2Tx MXene nanolamellas (Rh NS/MXene) via a convenient stereoassembly process. This unique design concept gives the resulting 2D/2D Rh NS/MXene heterostructure intriguing textural features, including large accessible surface areas, strong “face-to-face” interfacial interactions, homogeneous Rh nanosheet distribution, ameliorative electronic structure, and high electronic conductivity. As a consequence, the as-prepared Rh NS/MXene nanoarchitectures exhibit exceptional electrocatalytic methanol oxidation properties in terms of a large electrochemically active surface area of 126.2 m2 g−1Rh, a high mass activity of 1056.9 mA mg−1Rh, and a long service life, which significantly outperform those of conventional particle-shaped Rh catalysts supported by carbon black, carbon nanotubes, reduced graphene oxide, and MXene matrixes as well as the commercial Pt nanoparticle/carbon black and Pd nanoparticle/carbon black catalysts with the same noble metal loading amount. Density functional theory calculations further demonstrate that the direct electronic interaction at the well-contacted 2D/2D heterointerfaces effectively enhances the adsorption energy of Rh nanosheets and induces a left shift of the d-band center, thereby making the Rh NS/MXene configuration suffer less from CO poisoning. This work highlights the importance of rational heterointerface design in the construction of advanced noble metal/MXene electrocatalysts, which may provide new avenues for developing the next-generation DMFC devices.