Electrocatalyst For Methanol Oxidation Research Articles

Degradation of platinum electrocatalysts for methanol oxidation by lead contamination

Platinum exhibits high electrocatalytic activity toward various reactions but might be poisoned by some species. This communication reports a new finding that the electrocatalytic activity of platinum for methanol oxidation will be largely lost in a lead-contaminated environment. This activity loss is demonstrated in an electrochemical cell using a lead counter electrode for measuring the activity of platinum electrode towards methanol oxidation. The recorded methanol oxidation current in this cell is significantly decreased compared with that using a platinum counter electrode. The possible mechanism is related to the adsorption of trace lead ions from the lead counter electrode, as confirmed by comparing the calculated binding energies of platinum and lead ions with oxygen ion. This report is of great importance for reliably designing and efficiently managing direct methanol fuel cells, because trace lead might be present in various components in the fuel cell systems or in air and attention should be paid to its negative effect.

Highly graphitized carbon-wrapped PtFeCo alloy with enhanced durability and activity toward methanol electro-oxidation

Exploring efficient strategies to construct durable and active Pt-based electrocatalysts toward methanol oxidation reaction (MOR) remains great significance for the application of direct methanol fuel cells (DMFCs). Here, we report a facile pyrolysis procedure for fabricating carbon layer wrapped PtFeCo alloy nanoparticles supported on nitrogen-doped carbon nanotubes (NCNT). Physical characterizations demonstrate that the nitrogen-doped carbon support is highly graphitized and the PtFeCo particles are firmly wrapped by the graphitized carbon. Since the wrapping of highly graphitized carbon effectively prevents PtFeCo alloy from metal dissolution, the durability of the synthesized PtFeCo/Co–NCNTa catalyst has been substantially improved, remaining about 76% of its initial mass activity after 1000 cycles of durability test in acid condition. In addition, due to the strain and ligand effects caused by alloying Pt with Fe and Co, the PtFeCo/Co–NCNTa catalyst exhibits a greatly enhanced mass activity of 4.2-fold and a specific activity of 6.3-fold higher than those of commercial Pt/C-JM catalyst. Consequently, this work may provide an effective route for preparing durable and active Pt-based catalysts for methanol electro-oxidation.

PANI-ZnO/Pt–Ru electrocatalyst for methanol oxidation: Synthesis, characterization, electrocatalytic performance and artificial neural network modeling

In methanol oxidation, fabrication of novel electrocatalysts consisted of a lower loading of precious metals like platinum and ruthenium as well as possessing great electrocatalytic performance is of interest. One approach is to use an appropriate substrate. In this study, Polyaniline-Zinc oxide (PANI-ZnO) nanocomposites were prepared by polymerization method. Then, PANI-ZnO/Pt–Ru electrocatalyst was fabricated using the synthesized nanocomposites as a platinum and ruthenium (Pt–Ru) substrate. Field Emission Scanning Electron Microscopy (FESEM) was applied to study the morphology of the samples, while X-ray diffraction (XRD) analysis and Fourier Transform Infrared Spectroscopy (FTIR) were used to evaluate their phase structure and chemical groups, respectively. Electrochemical behaviors of fabricated PANI-ZnO/Pt–Ru electrocatalyst in the oxidation of methanol were specified via linear sweep voltammetry (LSV), cyclic voltammetry (CV), and chronoamperometry (CA) methods. The current density of PANI-ZnO/Pt–Ru was 91.14 mA/cm2, which was about 15% greater than the current density of Pt/Ru. This reflects the high catalytic performance of the electrocatalyst in the presence of nanocomposites. The electrochemically active surface area of the PANI-ZnO/Pt–Ru and Pt–Ru electrocatalysts are 37.72 m2/g and 21.22 m2/g, respectively. This increase is due to the specific morphology in the structure of nanocomposites. In general, these findings exhibited that the presence of PANI-ZnO support could enhance the catalytic performance and stability of Pt–Ru electrocatalysts. Besides, artificial neural network (ANN) model was used to predict the rate-determining reaction in methanol oxidation at different electrodes and the results indicated the efficiency of the model for forecasting.

Ultra-fine bimetallic FeCoP supported by N-doped MWCNTs Pt-based catalyst for efficient electrooxidation of methanol

Herein, novel ultra-fine bimetallic phosphides immobilized by N-doped multi-walled carbon nanotubes platinum-based catalyst (Pt-FeCoP/NCNT) has been fabricated by in suit growth of bimetallic hydroxide onto polyvinyl pyrrolidone (PVP)-coated multi-walled carbon nanotubes (MWCNTs), which is subsequently subjected to carbonization and sodium borohydride reduction treatments. In this system, PVP serves as the surfactant and doped nitrogen source, rendering the bifunctional effect: making the MWCNTs surface hydrophilic and thus facilitates the homogeneous growth of bimetallic hydroxide (FeCo-LDH). Besides, it provides nitrogen-doped structure after calcination, improving the overall electrical conductivity of the catalyst. Moreover, the introduced bimetallic phosphides deliver the enhanced co-catalytic effect compared with the monometallic phosphides, thus rendering the remarkable electrocatalytic activity (1221 mA mg-1Pt). In addition, this catalyst also maintains better anti-CO poisoning capability and long terms stability in comparison with others in this study. Thereby, this experiment provides the new inspiration for rational construction of high-efficiency metal phosphide platinum-based catalysts.

Hierarchical ternary ZnCoFe layered double hydroxide as efficient adsorbent and catalyst for methanol electrooxidation

Layered double hydroxide (LDH) was developed as a strong adsorbent material for the removal of organic dyes from wastewater. In this study, Zn–Co–Fe/LDH with a molar ratio of 2:2:1 was synthesized by the co-precipitation method. The characterization revealed a high degree of crystallinity as well as a lamellar structure. Additionally, Zn–Co–Fe/LDH was examined for wastewater treatment from cationic methylene blue (MB) under different adsorption parameters. When the initial concentration of MB was 100 mg/L, the adsorptivity reached 88.6% at pH 7 using 0.1 g of LDH. The pseudo-second-order kinetic model best described MB adsorption onto Zn–Co–Fe/LDH. The equilibrium adsorption data were obeyed by both the Langmuir and Freundlich models. The equilibrium parameter (RL) value for MB adsorption onto Zn–Co–Fe/LDH was calculated to be 0.571 indicating that the adsorption is favorable. The adsorption capacity of MB (58.26 mg/g) has been successfully obtained by Zn–Co–Fe/LDH from wastewater. Temperature experiments were conducted at 25, 35, 45, and 55 °C to investigate the thermodynamic parameters ΔH°, ΔS°, and ΔG°. The calculated values show exothermic and non-spontaneous adsorption processes. The results revealed that MB removal mechanisms involved physical and chemical adsorption. After calcining the waste material at different temperatures, Zn–Co–Fe/LDH/MB at 400 °C showed the highest pore radius (6.387 nm) and indicated the highest performance for methanol oxidation with a current density of 41.11 mA/cm2 at 50 mV/s and 3 M methanol. This study presented a novel method for employing LDH residue as a catalyst in direct methanol fuel cells (DMFCs).

Non-precious Sn as alternative substitute metal in graphene-based catalysts for methanol electrooxidation

Non-precious Sn as alternative substitute metal in graphene-based catalysts for methanol electrooxidation

Graphene Supported Pd-Cu Bimetallic Nanopartilces as Efficient Catalyst for Electrooxidation of Methanol in Alkaline Media

Graphene Supported Pd-Cu Bimetallic Nanopartilces as Efficient Catalyst for Electrooxidation of Methanol in Alkaline Media

Electrochemically Corroded Thick Microporous N-C Layer Encapsulated Pt/C as Highly Active and Ultra-Highly Stable Electrocatalyst for Methanol Oxidation and Oxygen Reduction Reaction in Acidic Media

Electrochemically Corroded Thick Microporous N-C Layer Encapsulated Pt/C as Highly Active and Ultra-Highly Stable Electrocatalyst for Methanol Oxidation and Oxygen Reduction Reaction in Acidic Media

Platinum-Nickel Alloy Supported on Nitrogen-Doped Carbon Modified Titanium Nitride Nanotubes Derived from Metal Organic Frameworks as an Efficient Catalyst for Methanol Electrooxidation

Platinum-Nickel Alloy Supported on Nitrogen-Doped Carbon Modified Titanium Nitride Nanotubes Derived from Metal Organic Frameworks as an Efficient Catalyst for Methanol Electrooxidation

Novel rhombus-shaped cerium oxide sheets as a highly durable methanol oxidation electrocatalyst and high-performance supercapacitor electrode material

In this work, novel rhombus-shaped cerium oxide sheets (RCOS) were prepared using a facile, soft-chemical approach that was low cost, scalable, eco-friendly, and industrially viable. The structural and surface chemical properties were studied using spectroscopic and electron microscopic techniques. The synthesized RCOSs were used for the methanol oxidation reaction and supercapacitor studies. The RCOSs showed a current density of ∼227 mA cm–2 with an onset potential of ∼0.37 V. The electrocatalyst activity retention was 92% of the initial activity after 500 CV cycles. A specific capacitance of 481 F g–1 at a scan rate of 5 mV s–1 was observed for supercapacitor application. The specific capacitance retention was ∼83% after 500 cycles. The huge specific surface area and conductivity associated with cerium oxide sheets were responsible for the enhanced electrochemical properties. This is the first report on the synthesis of rhombus-shaped cerium oxide sheets, which leads to new avenues for synthesizing novel cerium-based electrode materials.

Engineering PtCu nanoparticles for a highly efficient methanol electro-oxidation reaction.

Achieving a highly efficient and durable methanol electro-oxidation catalyst in acid media is critical for the practical utilization of direct methanol fuel cells (DMFCs) at the commercial scale. Herein, we report a facile and effective one-pot strategy for the synthesis of carbon-supported PtCu alloy nanoparticles (PtCu NPs) with a Pt-rich surface, small particle size and uniform dispersion. The as-prepared PtCu NPs with the optimal alloy composition (Pt2Cu) exhibit a significantly improved electrochemical methanol oxidation reaction performance in terms of a high activity, superior CO tolerance and remarkable durability, in contrast to those of commercial Pt/C catalysts in acid media. Particularly, the Pt2Cu/C catalyst exerts a 4.5 times enhancement in the mass activity and a larger If/Ib value compared to those of commercial Pt/C (Pt/Ccomm). The enhanced catalytic activities can be ascribed to the high utilization of Pt and the high index facets of the surface. Also, the addition of Cu downshifts the d-band center of Pt and improves the CO tolerance during the methanol oxidation reaction process. This work provides an efficient strategy for designing desired Pt-based alloys for various catalytic reactions.

Cobalt nanoparticles introduced to activated carbon, CoNP/AC, as an effective electrocatalyst for oxidation and determination of methanol and ethanol

Addressed herein, a glassy carbon electrode was modified by cobalt nanoparticles stuck to the activated carbon (CoNP/AC/GCE). The electrocatalytic oxidation of methanol and ethanol on the surface of the modified electrode in acidic setting was investigated using cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry as the first report. The effect of some parameters such as the potential scan rate, type of electrolyte solution and concentration effect of methanol and ethanol on the modified electrode was investigated. The kinetic parameters such as I0 (exchange current) and k0 (intrinsic heterogeneous rate constant) for methanol and ethanol were obtained through Tafel plots. By comparing the values obtained for I0 and K0, it would be clear that the effect of electrode modification on the electro-oxidation kinetics of ethanol and methanol is very significant. Finally, the response trends for electrooxidation of the alcohols by the CoNP/AC/GCE confirmed the quantitative application of the modified electrode.

Electrodeposited palladium as efficient electrocatalyst for hydrazine and methanol electro-oxidation and detection

Electrodeposited palladium was used as an electrocatalyst for electrochemical oxidation of hydrazine and methanol and the development of a sensitive platform for their detection. The electrochemical behavior of the electrode was evaluated by cyclic voltammetry (CV) while electroanalytical properties were determined by means of differential pulse voltammetry (DPV). The electrodeposited Pd catalyst exhibited good electrocatalytic activity towards the oxidation of hydrazine in neutral solution and methanol oxidation in alkaline solution. Under optimized DPV conditions, the electrodeposited Pd electrode shows good sensing capability in hydrazine and methanol detection.

High entropy spinel metal oxide (CoCrFeMnNi)3O4 nanoparticles as novel efficient electrocatalyst for methanol oxidation and oxygen evolution reactions

In this work, (CoCrFeMnNi)3O4 high entropy spinel oxide-based electrocatalyst is prepared using a facile soft chemical process. The synthesized catalyst has a spherical morphology. The formation of the pure phase material is confirmed using spectroscopic and microscopic studies. The prepared material is used as an electrocatalyst for the methanol oxidation and oxygen evolution reactions. The slurry of the as-synthesized material is coated on nickel foam and used as a working electrode. For methanol oxidation, the catalyst showed a specific current density of ~335 mA cm−2. The observed mass-activity of the catalyst is ~110 mA mg−1 with an observed onset potential of ~0.45 V. For the oxygen evolution reaction, the onset potential of (1.45 V vs. RHE) is observed with a low overpotential of 220 mV at 10 mA cm−2. The corresponding Tafel slope is ~100 mV dec−1. These results showed that the prepared high entropy oxide showed efficient electrocatalytic activity, and they are promising for methanol oxidation and oxygen evolution reactions. This is the first report demonstrating the spinel-type high entropy oxide nanoparticles in electrocatalysis to the best of our knowledge.

A non-noble, low cost, multicomponent electrocatalyst based on nickel oxide decorated AC nanosheets and PPy nanowires for the direct methanol oxidation reaction

The multicomponent electrocatalyst is a low-cost composite material exhibiting excellent catalytic activity suitable for methanol oxidation reactions (MOR). In this work, we report a glassy carbon electrode modified nickel oxide nanospheres (NiO) decorated biomass-derived activated carbon (AC) nanosheets and polypyrrole (PPy) nanowire, electrocatalyst (NiO_AC@PPy/GCE) for direct methanol oxidation fuel cell (DMFC) application. The SEM micrographs reveal the nanosheets and nanowire-like morphology of AC and PPy decorated with NiO nanospheres which provide a high surface area with electrocatalytic activity, and stability for MOR. The NiO_AC@PPy/GCE exhibits a high current density of 551 mA/mg at a low onset potential of 0.5 V (vs Ag|AgCl) towards electro-oxidation of 0.5 M methanol (MeOH) in an alkaline medium. This superior performance of the NiO_AC@PPy/GCE over other reported metal-oxides based electrocatalysts is attributed to the synergistic effect of the NiO_AC@PPy electrocatalyst, wherein NiO provides electrocatalytic active sites for MOR via Ni2+/Ni3+ redox couple while the PPy and AC contribute towards the chemical stability and electrical conductivity of the electrode, respectively. The electrode shows 79% of capacity retention after 10,000 s of chronoamperometry displaying excellent chemical stability with reduced effect of CO intermediate poisoning at the electrode surface. This excellent stability and overall performance of the NiO_AC@PPy proves it as an ideal, low-cost non-noble electrocatalyst for DMFCs.

Fabrication of Metal (Cu and Cr) Incorporated Nickel Oxide Films for Electrochemical Oxidation of Methanol

Methanol electrochemical oxidation in a direct methanol fuel cell (DMFC) is considered to be an efficient pathway for generating renewable energy with low pollutant emissions. NiO−CuO and Ni0.95Cr0.05O2+δ thin films were synthesized using a simple dip-coating method and tested for the electro-oxidation of methanol. These synthesized electrocatalysts were characterized by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. Different electrochemical techniques were used to investigate the catalytic activity of these prepared electrocatalysts for methanol oxidation, including linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). In the presence of 0.3 M methanol, the current densities of NiO−CuO and Ni0.95Cr0.05O2+δ thin films were found to be 12.2 mA·cm−2 and 6.5 mA·cm−2, respectively. The enhanced catalytic activity of NiO−CuO and Ni0.95Cr0.05O2+δ thin films may be a result of the synergistic effect between different metal oxides. The Chronoamperometry (CA) results of the mixed metal oxide thin films confirmed their stability in basic media. Furthermore, the findings of electrochemical impedance spectroscopy (EIS) of mixed metal oxide thin films demonstrated a lower charge transfer resistance as compared to the pure NiO, CuO, and Cr2O3 thin films.

Platinum doped titanium dioxide nanocomposite an efficient platform as anode material for methanol oxidation

TiO2@Pt nanocomposite was synthesized using a simple one-step coprecipitation method as an electrocatalyst for methanol oxidation. Pt nanoparticles were supported by using TiO2 as a support material, thereby providing strong metal-support interactions. The TiO2@Pt nanocomposite characterized by Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-ray analysis (EDX) revealed the spherical shape of TiO2 crystalline matrix with finely dispersed Pt nanoparticles. In the powder X-ray diffraction (XRD) analysis, the diffraction peaks observed for the TiO2 and TiO2@Pt nanocomposites were composed of mixed phases of anatase and rutile. Electrochemical performances are evaluated in an aqueous 0.1 M KOH electrolyte and 0.1 M CH3OH as a target analyte. The Pt@TiO2 nanocomposite showed high electrocatalytic activity towards methanol oxidation, the results indicated that the bare Pt electrode has catalyzed the oxidation of methanol with a strongly weak oxidation peak (J = 0.25 mA/cm2), while TiO2 modified Pt electrode which showed higher catalytic activity towards methanol oxidation with a current density of 0.48 mA/cm2. The methanol oxidation was increased compared to a commercially available Pt/C reference catalyst, as shown by a shifted methanol oxidation peak potential and an increased peak current density. As demonstrated by cyclic voltammetry, these increased activities have been clarified by enhanced methanol oxidation activities. An enhanced methanol oxidation activity is attributed to the metal support interaction due to TiO2 nanoparticles, therefore resulting in a weak CO chemisorption on the surface of Pt. Finally, with such valuable features of electrochemical sensitivity and great catalytic activity, the synthesized TiO2@Pt-3 nanocomposite is used as the anode material for methanol fuel cell application.

Synthesis and characterization of palladium nanoparticles-corannulene nanocomposite: An anode electrocatalyst for direct oxidation of methanol in alkaline medium

• Catalyst based on PdNPs and corannulene has been developed for methanol fuel cells. • Corannulene is used as novel Supporting Material in fuel cell applications. • The catalyst exhibits high current density and long-term stability. • Corannulene support has reduced the loading of PdNPs. Herein a facile route to anchor transition metal nanoparticles on a bowl-shaped carbon material has been described to prepare a novel nanocomposite as an anode electrode for fuel cell applications. To accomplish this, palladium nanoparticles (PdNPs) have been electrochemically decorated on corannulene-based curved carbon material. The proposed catalyst was structurally and morphologically characterized by various techniques. The performance of the catalyst was evaluated by electrochemical techniques such as CV, EIS, LSV, and CA. The PdNPs@Corannulene catalyst shows high MOR activity of 102.1 mA/cm 2 in an alkaline medium and good stability when compared with most of the reported Pd-based catalysts and Pd/C. The developed electrocatalyst exhibited a high surface area, good current density, excellent anti-poisoning ability, and superior catalytic activity towards methanol oxidation. The results presented herein revealed that molecularly curved carbon-corannulene as a novel support material in the design of nanostructured catalysts will open a new avenue for high-performance fuel cell applications.

Synthesis the flower-like N-C/NiO nanocomposites by one-pot hydrothermal method as efficient electrocatalyst for methanol oxidation in alkaline electrolyte

Currently, Substituting methanol oxidation reaction with a low theoretical potential for water oxidation reaction is one of the hotspots in the study of water splitting to hydrogen production. In this work, N-C/NiO nanocomposites with different morphologies were synthesized by one-pot hydrothermal method. Interestingly, the tremella-like N-C/NiO nanocomposites turned into looser flower-like structure at the existence of N-C-SiO 2 nanosheets supporting in the hydrothermal process. Meanwhile, the silica in the N-C-SiO 2 nanosheets was removed by urea in hydrothermal reaction. The introduction of the N-C-SiO 2 nanosheets has a vital influence to enhance the electrochemical performance of the N-C/NiO nanocomposites. The flower-like N-C/NiO nanocomposites exhibit large electrochemically active surface area and superior electrocatalytic performance for methanol oxidation reaction (MOR) in alkalic electrolyte. It displays excellent electrocatalytic activity with a highly mass activity (3298 mA mg −1 ) and long-time stability (remain 50% after 36,000 s) toward MOR, which are 35.0 and 2.9 folds higher than that of the commercial 10%-Pt/C, respectively. The flower-like N-C/NiO nanocomposites were synthesized by one-pot hydrothermal method, which exhibits superior electrocatalytic activity and long-time stability for the methanol oxidation in alkaline electrolyte. • The flower-like N-C/NiO nanocomposites were synthesized by a facile one-pot hydrothermal method. • The N-C-SiO 2 nanosheets supporting induced the formation of the loose flower-like structure. • The flower-like N-C/NiO nanocomposites shows excellent electrocatalytic activity for MOR. • The flower-like N-C/NiO nanocomposites exhibits outstanding long-time stability towards MOR.

Fabrication of nanocomposite networks using Pd nanoparticles/Polydiphenylamine anchored on the surface of reduced graphene oxide: An efficient anode electrocatalyst for oxidation of methanol

Direct methanol fuel cells (DMFCs) are an essential aspect of electricity and fuel concerns. Herein, we report a new combination of Palladium nanoparticles anchored on polydiphenylamine with reduced graphene oxide network (rGO/PDPA/Pd) nanohybrid synthesized via an in-situ chemical strategy. The rGO/PDPA/Pd electrocatalyst shows excellent electrocatalytic activity, lower oxidation potential (−0.1 V), improved current density (2.85 mA/cm2), excellent cyclic stability (94%), and longevity (1200 s) towards methanol oxidation reaction (MOR) in the alkaline medium, when compared to commercial Pd/C electrocatalyst. Significantly, the forward oxidation peak potential of rGO/PDPA/Pd electrocatalyst was shifted negatively by 110 mV as compared to commercial Pd/C electrocatalyst. These results suggest that rGO/PDPA/Pd electrocatalyst is considered as an effective anode catalyst for DMFCs.