Methanol Electrocatalysis Research Articles

Energy‐Saving Hydrogen Production from Methanol Electrocatalysis Catalyzed by Molybdenum Phosphide/Nitrogen‐Doped Carbon Polyhedrons Supported Pt Nanoparticles

Comprehensive SummaryImproving the catalytic efficiency and anti‐poisoning ability of Pt‐based catalysts is very critical in methanol electrolysis technology for high‐purity hydrogen generation. Herein, the nitrogen‐doped carbon polyhedrons‐encapsulated MoP (MoP@NC) supported Pt nanoparticles were demonstrated to be effective for methanol electrolysis resulting from the combined advantages. The nitrogen‐doped carbon polyhedrons not only greatly enhanced the conductivity but also effectively prevented the aggregation of MoP to offer Pt anchoring sites. The electronic structure modification of Pt from their interaction reduced the adsorption energy of CO*, resulting in good CO‐poisoning resistance and accelerated reaction kinetics. Specifically, Pt‐MoP@NC exhibited the highest peak current density of 106.4 mA·cm–2 for methanol oxidation and a lower overpotential of 28 mV at 10 mA·cm–2 for hydrogen evolution. Energy‐saving hydrogen production from methanol electrolysis was demonstrated in the two‐electrode systems assembled by Pt‐MoP@NC which required a low cell voltage of 0.65 V to reach a kinetic current density of 10 mA·cm–2 on the glass carbon system, about 1.02 V less than that of water electrolysis.

NiCoMo nanoparticles as an efficient electrocatalyst for methanol electro‐oxidation in alkaline media

AbstractUsing the electrospinning approach, various percentages of less expensive metal alloy‐decorated nanofiber catalysts have been successfully made as a substitute for platinum in direct methanol fuel cells (DMFC). This work focuses on the synthesis and characterization of catalysts with metal fixed ratio of 20% wt for DMFC applications, specifically Ni/CNFs, Co/CNFs, and NiCoMo/CNFs. The catalysts are characterized using various techniques, including x‐ray diffraction, scanning electron microscope, transmission electron microscopy, energy dispersive x‐ray, and electrochemical measurements. All the prepared samples, regardless of the metal concentration, had good nanofiber form and a distinct nanoparticle appearance, according to the scanning electron microscope (SEM). Chromatography, scan rate, response time, and cyclic voltammetry all were used to examine the samples' ability to perform methanol electrocatalysis. When Mo is added to Ni with Co, the electrooxidation reaction's activation energy and electrode stability both increase. With a starting potential of 0.22 V, the maximum current density in the NiCoMo/CNF sample was 99.8 mA/cm2 at 0.6 V. To electrooxidize methanol, our electrocatalysts combine diffusion control with kinetic‐limiting processes. This work has shown how to create an effective NiCoMo based methanol electrooxidation catalyst using a special technique.

Electrocatalysis of methanol at the surface of carbon paste electrode modified with composite of Cu-Al-layered double hydroxide and graphene oxide

Electrocatalysis of methanol at the surface of carbon paste electrode modified with composite of Cu-Al-layered double hydroxide and graphene oxide

Engineering low platinum loaded defects enriched PtxCo wrapped by carbon layers for efficient methanol electrooxidation with CO-free dominant

Constructing robust nanomaterials with surface defects is a promise way for high-efficiency methanol electrocatalysis together with minimizing poisoning of adsorbed CO. To this end, low platinum (Pt) loaded (6% wt) defects enriched PtCo alloy wrapped by carbon layers (V-PtxCo@NC/C) enabled via facile pyrolysis. In the pyrolysis process, the metal salts are subjected to alloying and dealloying process under high temperature annealing combined with etching treatment to construct defects and boundaries enriched PtCo alloy. These defects and boundaries enriched structure can provide abundant active edge atoms with low coordination numbers as well as are beneficial for more exposed active sites of Pt, rendering the large electrochemical surface areas and changing the reaction properties for intermediates of methanol oxidation. In-situ Fourier transform infrared spectroscopy shows that the catalyst follows direct HCOO− pathway with CO-free dominant. Thus, presenting excellent mass activity (1328 mA mg−1Pt) in acid medium. Moreover, benefiting from the protection of carbon layers, possible dissolution of metallic can be diminished. Therefore, the catalyst delivers superhigh stability and can maintain 80% of mass activity after 1000 cycles. This work poses a new avenue for the design of cost-effective catalyst.

Nanoscale PtCuMn Hexapods for Methanol Electrocatalysis

Nanoscale PtCuMn Hexapods for Methanol Electrocatalysis

Synthesis of Cu@Pt‐Pd Ternary Metallic Composites for Efficient Electrocatalysis of Methanol

AbstractAn electrochemical preparation method of Cu@Pt‐Pd ternary metallic composite, which is used as excellent catalytic materials to oxide methanol under alkaline conditions, is reported in this work. Cu polyhedron as nuclei and Pt‐Pd alloy nanoclusters as shells of Cu@Pt‐Pd are proved by X‐ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The activities of composite materials are examined by linear sweep voltammetry, cyclic voltammetry, and chronoamperometry. The catalytic activity is investigated by modulating metal element proportion of Pt and Pd. The highest mass activity of Cu@Pt11.3Pd10.1 is 2387 mA mgPt+Pd−1 for methanol oxidation reaction. The mass activity of Cu@Pt11.3Pd10.1 is 3.42 folds relative to Pt/C catalysts. Compared with Pt/C catalysts, Cu@Pt‐Pd composites have higher CO resistance. This enhanced catalytic performance is closely related to its alloy structure through ligand and strain effects.

NiFexP@NiCo-LDH nanoarray bifunctional electrocatalysts for coupling of methanol oxidation and hydrogen production

NiFexP@NiCo-LDH/CC nanosheet core-shell nanoarrays electrocatalysts are prepared by electrodeposition and phosphating methods for relatively low potential production of H2 and value-added formate in methanol/water electrolysis systems. During the oxygen evolution reaction process, the over potential is 269 mA at the current density of 50 mA cm−2 and the Tafel slope is 97 mV dec−1. It also realizes the stable long-term electrocatalysis of methanol to formate under high current density and maintains a relatively high Faraday efficiency of 100%. Meanwhile, the energy saving is higher than 10% in the methanol oxidation and co-hydrogen production system that achieves great attention. The superior performance of NiFexP@NiCo-LDH/CC bifunctional electrocatalysts might be beneficial from the interaction to Ni and Fe bimetallic extranuclear electrons that exposes more active sites.

Synthesis of Ptcumn Hexapods as Efficient Catalysts for Methanol Electrocatalysis

Synthesis of Ptcumn Hexapods as Efficient Catalysts for Methanol Electrocatalysis

Electrocatalytic study of NiO-MOF with activated carbon composites for methanol oxidation reaction

In this work, the methanol oxidation reaction is investigated on Ni based metal organic frameworks (MOF) and its composites with biomass derived activated carbon. NiO-MOF and composites with activated carbon were synthesized using hydrothermal method. SEM, EDX, and XRD, FTIR, TGA techniques were used for characterization of composites. The electrochemical activity of catalysts for oxidation of methanol was tested using cyclic voltammetry (CV) in 1 M KOH and 3 M CH3OH on glassy carbon electrode in three electrode setup. The electrochemical performance shows the effect of activated carbon concentration on methanol oxidation. The electro-oxidation catalyzed by NiO-MOF with activated carbon (40 mg) composite exhibits a peak current density of 182.72 mA/cm2 at 0.89 V potential with a scan rate of 50 mV/s making it a potential catalyst for electrocatalysis of methanol.

CuWO4: A promising multifunctional electrode material for energy storage as in redox active solid-state asymmetric supercapacitor and an electrocatalyst for energy conversion in methanol electro-oxidation

• CuWO 4 has been prepared by quick co-precipitation route within 20 min. • ASC device shows specific capacity of 103 mAh g −1 at 1 A g −1 . • ASC device shows retention of 119.4% of initial capacity after 5000 cycles. • ASC device exhibits energy density of 103 Wh kg −1 at power density of 0.95 kW kg −1 . • For methanol oxidation, the CuWO 4 electrode exhibits 38 mA cm −2 at 0.5 V. This article reports the formation the multifunctional CuWO 4 nanoparticles towards the application of gel electrolyte-based supercapacitor and methanol electro-oxidation. The CuWO 4 nanoparticles were synthesized by a quick chemical co-precipitation route within 20 min. The hydrated precursor was treated at 600 °C for 2 h to convert in to final CuWO 4 products. Structural features of the prepared CuWO 4 were investigated by means of X-ray diffraction, electron microscopies, Fourier transform infrared spectroscopy, Raman and X-ray photoelectron spectroscopy. The CuWO 4 electrode exhibits the specific capacity of 415 mAh g −1 at a current density of 2 A g −1 in three electrode configurations in 1 M Na 2 SO 4 and 3 mM KI mixed electrolyte. The electrode shows retention of 86.1% of its initial specific capacity after 10,000 galvanostatic charge–discharge cycles at 30 A g −1 . An asymmetric solid-state device was assembled by sandwiching the PVA-Na 2 SO 4 and 3 mM KI gel electrolyte in between the CuWO 4 nanoparticle and activated carbon electrodes. The device shows the specific capacity of 103 mAh g −1 at a current density of 1 A g −1 and device shows the retention of 93.4% after 5000 galvanostatic charge–discharge cycles at 7 A g −1 . The hybrid device exhibits energy density of 103 Wh kg −1 at power density of 0.95 kW kg −1 . In electro-catalysis of methanol, the CuWO 4 electrode exhibits the high current density of 38 mA cm −2 at 0.5 V and onset potential achieved as 0.38 V in mixed solution of 1 M KOH and 0.5 M methanol.

A novel electrodeposited poly(melamine)-palladium nanohybrid catalyst on GCE: Prosperous multi-functional electrode towards methanol and ethanol oxidation

Herein, a novel Poly (melamine) have been successively electrodeposited on glassy carbon electrode and decorated by Pd nanoparticles (Pd NPs) subsequently to fabricate Poly (melamine) – Pd nanocomposite. Structural geometry, morphological view, and elemental composition analysis were ensured by X-ray diffractogram, scanning electron microscope, and X-ray photoelectron spectroscopy. The electrodeposited Poly (melamine) (PME) material depicts an interconnected nano rod (50 nm) morphology leads to a nano exploder (~150 nm) arrangement. Spherical shaped Pd decorated PME morphology was obtained for GC\\PME-Pd NPs composite (150 nm). The electrocatalytic activity of the fabricated anode electrocatalyst was examined by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry methods. The modified GC\\PME-Pd NPs composite electrode validates superior electrocatalytic behaviour towards methanol and ethanol oxidation in alkaline background. Besides, the electrochemical surface area and electrocatalytic behaviour make it a greater anode catalyst towards methanol and ethanol oxidation. The synergic effects amid the Poly (melamine)-Pd NPs composite enhances the catalytic activity, mechanical stability on the electrocatalysis of methanol and ethanol oxidation reaction superior than modified Poly (melamine) electrode. Hence, the fabricated anode electrocatalyst is proficient to get realistic approach towards the progression in the direct alcohol (methanol and ethanol) oxidation reaction in direct alcohol fuel cells (DAFCs) applications.

Physicochemical Properties of Carbonized Bacterial Cellulose and Its Application in Methanol Electrocatalysis

Physicochemical Properties of Carbonized Bacterial Cellulose and Its Application in Methanol Electrocatalysis

A study on divergent functional properties of sphere-like CuWO4 anchored on 2D graphene oxide sheets towards the photocatalysis of ciprofloxacin and electrocatalysis of methanol

Exploration of the novel and proficient nanostructured material for the utilization of energy and environmental applications is a major concern to the researchers. Herein, we fabricated sphere-like copper tungstate (CuWO4) anchored on graphene oxide nanocomposite (CuWO4–GO NCs) via simple hydrothermal treatment followed by sonication progress. The successful formation of CuWO4–GO nanocomposite was confirmed by various spectroscopic techniques including XRD, SEM, TEM, EDX, DRS–UV and XPS analysis. For the first time, the as-prepared CuWO4–GO NCs were utilized as a bifunctional catalyst for the photodegradation of ciprofloxacin (CF) and electrocatalytic oxidation of methanol. The UV–Visible spectroscopy results portrayed that the CuWO4–GO NCs degrade above 97% of CF aqueous suspension after 60 min of visible light irradiation with good repeatability and stability. Moreover, the CuWO4–GO NCs demonstrates excellent electrocatalytic performances towards the oxidation of methanol in an alkaline medium. In addition, the dielectric properties of the CuWO4–GO NCs were also analyzed and the results are well satisfied. The improved photocatalytic, electrocatalytic and electrical conductivity of CuWO4–GO NCs could ascribe to the strong electrostatic interaction between the CuWO4 and GO.

Direct Conversion of Methanol to Ethanol on the Metal‐Carbon Interface

AbstractDirect conversion of one‐carbon (C1) compounds to two‐carbon (C2) and multi‐carbon compounds remains a critical challenge for converting non‐petroleum resources to valuable chemicals or fuels. The key issue is the selective activation of C1 compounds, methanol, as well as the controlled formation of carbon‐carbon (C−C) bonds. Herein, we achieve the direct electrocatalytic methanol to ethanol, an important chemical and energy candidate, with methanol conversion, ethanol selectivity, and faradic efficiency of 257.0 g ⋅ m−2 ⋅ h−1, 95.1 %, and 12.5 %, respectively. Furthermore, the appropriate participation of water, as a by‐product from methanol electrocatalysis, in hydrogen evolution reaction (HER) facilitates electrocatalytic reaction of methanol. Mechanistic studies reveal hydroxymethyl and methyl radicals are formed on the electropositive low‐valent metal sites and electronegative carbon vacancies, respectively, and then combined with each other to form ethanol at the metal/carbon interface. This work opens a unique route for high‐efficient concerted redox conversion of methanol reactant to ethanol.

Platinum Monolayer Electrocatalysts for Methanol Oxidation

The direct methanol oxidation fuel cell (DMFC) holds great promise as a power source. It reached that stage as a result of extraordinary contributions of Shimshon Gottesfeld, whom we are honoring by this issue of JES. We briefly comment on his main contributions and, in this context, we present new catalysts for methanol oxidation. They comprise a platinum monolayer (PtML) under tensile strain that produce a large enhancement in the catalytic activity. PtML/Au(111), where PtML is stretched by over 4%, displayed a significantly enhanced activity. The tensile strain induced by Au(100) has a similar effect. In situ IRRAS study showed the oxidation of COHads to CO2. COads was not formed, which is a major breakthrough in methanol electrocatalysis. We synthesized Au Octahedra nanocrystals (NCs) enclosed with Au{111} facets and placed a PtML on them. This catalyst indicates a potential for practical application. Further improvements were achieved using Ru nanoclusters as co-catalyst. In another class of nanocatalysts, core-shell PdAuM (M = Co, Fe, Ni) nanoparticles served as substrates for PtML. Besides enhanced activity, a cost reduction is achieved. Incorporated in DMFC optimized by Shimshon Gottesfeld and his coworkers these catalysts may facilitate a long-awaited application of this power source.

Synthesis of a Pt/reduced graphene oxide/polydopamine composite material for localized surface plasmon resonance and methanol electrocatalysis

Pt NPs are synthesized and loaded with rGO onto ITO using polydopamine. The strongest LSPR effect corresponds to the optimal catalyst. The catalyst has a good anti-poison property against CO and shows good cycle stability.

A simple, cheap and effective methanol electrocatalyst based of Mn(II)-exchanged clinoptilolite nanoparticles

Clinoptilolite nanoparticles (NClin), prepared via ball-mill mechanical method, were ion-exchanged in Mn(II) solutions with different concentrations ranging from 0.1 to 1 mol L−1. After characterization of samples by XRD, TEM and BET techniques, the resulted Mn-exchanged nano-particles (Mn(II)-NClin) (and also Mn-exchanged micronized one: Mn(II)-MClin) were used for modification of carbon paste electrode (Mn(II)-NClin-CPE). These modified electrodes were applied in methanol oxidation reaction as a catalyst in strong basic pHs which caused to a significant decrease (920 mV) in overvoltage of the process with respect to the bare CPE. The best voltammetric response (CV) was obtained for the catalyst ion exchanged in 1 mol L−1 Mn(II) solution and also by using clinoptilolite nanoparticles with respect to micronized one (MClin). In the chronoamperometris studies, the average diffusion coefficients of 8.73 × 10−3 and 8.6 × 10−5 cm2 s−1 and also the mean ks values of 150 M−1 s−1 and 99 M−1 s−1 were obtained for Mn(II)-NClin/CPE and Mn(II)-MClin/CPE, respectively. CV behavior of the modified electrode was a diffusion controlling process in the absence of methanol, while it was controlled by surface confined process in the presence of methanol, confirming the important role of Mn(OH)2/MnOOH system in electrocatalysis of methanol in alkaline solutions.

Photoelectrochemical Properties of CuS-GeO2-TiO2 Composite Coating Electrode.

The ITO (indium tin oxide) conductive glass-matrix CuS-GeO2-TiO2 composite coating was generated via EPD (electrophoretic deposition) and followed by a sintering treatment at 450°C for 40 minutes. Characterizations of the CuS-GeO2-TiO2 composite coating were taken by SEM (scanning electron microscope), XRD (X-ray diffraction), EDX (energy dispersive X-ray), UV-Vis DRS (ultraviolet-visible diffuse reflection spectrum), and FT-IR (Fourier transform infrared spectroscopy). Results showed that CuS and GeO2 had dispersed in this CuS-GeO2-TiO2 composite coating (mass percentages for CuS and GeO2 were 1.23% and 2.79%, respectively). The electrochemical studies (cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization) of this CuS-GeO2-TiO2 composite coating electrode were performed in pH = 9.51 Na2CO3-NaHCO3 buffer solution containing 0.50 mol/L CH3OH under the conditions of visible light, ultraviolet light (λ = 365 nm), and dark (without light irradiation as control), respectively. Electrochemical studies indicated that this CuS-GeO2-TiO2 composite coating electrode had better photoelectrocatalytic activity than the pure TiO2 electrode in the electrocatalysis of methanol under visible light.

Negative resistance for methanol electro-oxidation on platinum/carbon (Pt/C) catalyst investigated by an electrochemical impedance spectroscopy

The poisoning of Pt-based catalyst occurs generally during methanol electro-oxidation. Though traditional electrochemical techniques have probed these issues intensively, it is amazing to find that the negative resistance presents in the intermediate potential zone during an electrochemical impedance spectroscopy (EIS) measurement. Based on the chemical reaction analysis, we establish an EIS model and make some numerical analyses, thus determining the specific EIS shapes and equivalent circuits relating to various potential zones. These results not only compensate the drawback for traditional electrochemical approaches, but also reveal the dynamic adsorption of CO and OH species on Pt surfaces, providing a chance for understanding bifunctional mechanism towards quantitative manners. Significantly, we clarify that the negative resistance begins from the maximum catalysis of methanol electro-catalysis and ends in the initial passive state on Pt surfaces, offering a tool for further improvement. Interestingly, our discovery for negative resistance is consistent with that in general electrochemical system, facilitating its extension and direction in future.

Pt nanoparticles on graphene – polyelectrolyte nanocomposite: Investigation of H2O2 and methanol electrocatalysis

Poly (diallyldimethylammonium chloride) (PDDA) functionalized graphene oxide (GO) decorated with Pt nanoparticles (PtNPs) was obtained and investigated. This hybrid nanocomposite material was morphologically characterized by several instrumental techniques like high-resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED) and X-ray diffraction (XRD). Good coverage of crystalline Pt nanoparticles was achieved, the average diameter being 2 nm, meanwhile in the absence of polyelectrolyte the average diameter increased up to 4 nm. The electrocatalytic properties of this hybrid nanocomposite against H2O2 and methanol were ascertained by cyclic voltammetry. A modified glassy carbon electrode (GC) was able to reduce H2O2 at positive potentials (starting from ∼150 mV vs. Ag/AgCl) meanwhile for methanol the ratio of the forward anodic peak current (If) to the reverse anodic peak current (Ib) was 1.42, indicating good tolerance of the catalyst towards the intermediate carbonaceous species accumulated on the electrode surface.