Performance For Methanol Electrooxidation Research Articles

Au-doped PtCu2 nanonetworks with interface-rich for enhancing methanol electro-oxidation performance

Regulating the near-surface structure of platinum-based alloys by inserting transition metal atoms can significantly improve the electro-oxidative performance of small organic molecules. So far, it is rarely reported that a small amount of Au element is introduced into the interior of Pt-based alloys as an active auxiliary to adjust the electrocatalytic activity and stability of Pt-based alloys with special morphologies. Herein, a stable three-dimensional (3D) Au-doped PtCu2/C (Au–PtCu2/C) catalyst with nanonetwork structure and abundant interfaces has been successfully developed, in which the oxyphilic Cu atoms and stable Au atoms are implanted into the whole and inside of the Pt-based nanonetwork, respectively. Detailed physical characterizations of the Au–PtCu2/C catalyst illustrate that the insertion of Au atoms generates core-shell-like nanonetwork, highly-open structure, strong electronic effect, and sufficient active sites. The well-designed Au–PtCu2/C catalyst exhibits superior mass activity (MA) of 2355 mA·mgPt−1 and long-term durability of 500 cycles toward methanol oxidation reaction (MOR) in an acidic medium. Notably, the MA of the Au–PtCu2/C catalyst is 7.3 folds and 1.3 folds that of the Pt/C (322 mA·mgPt−1) and PtCu2/C (1821 mA·mgPt−1) catalysts, respectively. The kinetic and thermodynamics studies indicate that the Au–PtCu2/C catalyst is superior to PtCu2/C and Pt/C catalysts in reducing the electrochemical activation energy of MOR, promoting the mass transfer of methanol molecules, and enhancing electronic conductivity. This work proposes an advanced strategy to fabricate efficient and durable electrocatalyst with excellent electrocatalytic MOR performance, thereby enabling catalysts with special morphology to have greater application potential in direct methanol fuel cell.

Universal interface-confined strategy for trough-like AgPtM (M=Ru, Ir, Sn) nanostructures for methanol electro-oxidation

AgPt-based tri-metallic electrocatalyst as an emerging electrocatalyst is demonstrated to have superior catalytic performance. However, it still lacks a universal synthesis strategy currently because of the participation of multiple precursors with different electrical reduction potentials, which is greatly limited to developing high-performance electrocatalysts. Here, a universal interface-confined strategy method is developed to transform the starting Ag nanowires into a series of novel AgPtM (M=Ru, Ir, Sn) alloy nanotroughs at water/air interface. Moreover, owing to their unique trough-like structure, rough surface and the electronic synergistic effect between oxyphilic metals and Pt component, the AgPtM (M=Ru, Ir, Sn) alloy nanotroughs all show enhanced electrocatalytic performance for methanol electro-oxidation. Notably, among all the prepared AgPtM (M=Ru, Ir, Sn) catalysts, the AgPtRu exhibits the best mass activity, ∼ 3.7 and ∼1.65 times higher than that of Pt/C and AgPt nanotroughs counterpart, respectively. This study not only develops a new promising electrocatalyst for methanol oxidation, also provides method guidance for the construction of advanced Pt-based tri-metallic electrocatalysts in practical direct alcohol fuel cell.

Leveraging Ligand and Composition Effects: Morphology-Tailorable Pt-Bi Bimetallic Aerogels for Enhanced (Photo-)Electrocatalysis.

Metal aerogels (MAs) are emerging porous materials displaying unprecedented potential in catalysis, sensing, plasmonic technologies, etc. However, the lack of efficient regulation of their nano-building blocks (NBBs) remains a big hurdle that hampers the in-depth investigation and performance enhancement. Here, by harmonizing composition and ligand effects, Pt- and Bi-based single- and bimetallic aerogels bearing NBBs of controlled dimensions and shapes are obtained by facilely tuning the metal precursors and the applied ligands. Particularly, by further modulating the electronic and optic properties of the aerogels via adjusting the content of the catalytically active Pt component and the semiconducting Bi component, both the electrocatalytic and photoelectrocatalytic performance of the Pt-Bi aerogels can be manipulated. In this light, an impressive catalytic performance for electro-oxidation of methanol is acquired, marking a mass activity of 6.4-fold higher under UV irradiation than that for commercial Pt/C. This study not only sheds light on in situ manipulating NBBs of MAs, but also puts forward guidelines for crafting high-performance MAs-based electrocatalysts and photoelectrocatalysts toward energy-related electrochemical processes.

Bimetallic nitrides Co3Mo3N nanosheets combined with phosphorus-doped carbon as superior Pt-based catalyst carriers for methanol electrooxidation reaction

Facile constructing novel and stable carrier of Pt-based catalyst for excellent methanol electrochemical is profitable. To this end, a clean and simple synthetic route is used to synthesize Pt supported by bimetallic nitride Co3Mo3N catalysts (Pt/Co–Co3Mo3N/PC). On the one hand, thanks to the intensive interaction between Co3Mo3N and Pt NPs and the ability of Co3Mo3N itself to provide adsorption OH by decomposing water; on the other hand, P-doped carbon brings an increase in defect sites for better anchoring of Pt NPs, the catalyst Pt/Co–Co3Mo3N/PC possesses excellent improved catalytic performance for methanol electrooxidation, in which the mass activity is 910 ​mA‧mg−1Pt, which is about 2.1 times that of Pt/C-JM. Additionally, the specific activity, anti-CO poisoning capability, and long-term stability of the catalyst are far outstanding to those of Pt/C-JM. The experimental approach in this paper also provides ideas for the commercial application of Pt-based catalysts.

Fe-doped hollow PtBi nanocages loaded on Bi2O2CO3-NC composite support with excellent methanol electrooxidation performance

A highly active and stable anode catalyst for direct methanol fuel cells is critical to commercialization. Therefore, we have synthesized a unique Fe-doped catalyst Fe–PtBi2/Bi2O2CO3-NC through the classical hydrothermal method and sodium borohydride reduction. Physical characterizations confirm the existence of Bi2O2CO3 nanosheets and successful loading of PtBi nanocages. It is the alternating layer arrangement of Bi2O2CO3, the bifunctional mechanism of PtBi alloy and the synergistic effect of each component that make the synthesized Fe–PtBi2/Bi2O2CO3-NC possess such remarkable methanol oxidation reaction activity (a mass activity of 9345 mA/mgPt in alkaline electrolyte). Moreover, electrochemical measurements also indicate that 51.7% of the mass activity was retained after 1 h durable operation, which is approximately 4.1 times than that of commercial Pt black. Fe–PtBi2/Bi2O2CO3-NC may be applied as a promising alkaline anode catalyst for direct methanol fuel cells due to its outstanding structure and performance. The specific work provides a reference for designing reliable structures and selection of doping elements to enhance the sluggish kinetics of methanol electrooxidation.

Interface engineering of PtCuMn nanoframes with abundant defects for efficient electrooxidation of liquid fuels

Precise design and synthesis of advanced Pt-based catalysts through modulation of the surface coordination environment at the atomic level are crucial for the industrial application of fuel cells. However, conventional surface engineering approaches are generally multistage processes. Herein, we report a simple one-step method to precisely synthesize a set of ternary PtCuMn nanoframes (multiple-pin and external branch structures) with high-index facets (HIFs) and high defect density via change of alcohol species, structure-directing agent and heating mode. Owing to the high density of abundant coordinatively unsaturated sites and the unique electronic effect of ternary alloys, the prepared PtCuMn nanoframes present excellent performance for methanol electrooxidation (MOR) and formic acid electrooxidation (FAOR). Specifically, the area specific current densities of PtCuMn with multiple-pin nanoframe morphology for MOR and FAOR are approximately 7.76 and 6.68 times higher, respectively, than those of Pt/C. More importantly, the catalysts show more stability compared with Pt/C. This proposed surface engineering approach not only realizes efficient architecture- and defect-controlled PtCuMn nanoframe electrocatalyst, but also provides fundamental insights into the roles of architecture and defects in renewable energy electrocatalysis.

Enhanced Methanol Electrooxidation Performance Based on Pt Cluster‐Decorated CuCoO2 on Carbon

AbstractNowadays, the high cost and poor durability of commercial catalyst Pt/C for methanol oxidation reaction have impeded the further development of direct methanol fuel cells. Herein, we firstly introduced a delafossite CuCoO2 to act as the support of noble metal Pt. The strong metal support interaction between Pt and CuCoO2, abundant hydroxide species and active sites on the surface of catalyst may be the key factors for enhanced performances of methanol oxidation. Pt‐CuCoO2/C achieved a mass activity of 1.16 A mgPt−1, which obtained 3.02 times enhancement compared with commercial Pt/C (0.38 A mgPt−1). The If/Ib value of Pt‐CuCoO2/C is 1.96, much higher than that of Pt/C (0.76), demonstrating favorable anti‐poisoning ability. After 200 times cycling, Pt‐CuCoO2/C still maintained 77.1 % of its initial activity, exhibiting superior COads intermediate tolerance and stability. Low cost, better performances and stability of Pt‐CuCoO2/C reveal that it can be seen as a hopeful catalyst.

Synthesis of PtCuFe alloy nanoframes with high-index facets for efficient electro-oxidation of liquid fuels

By controlling the structure, surface and composition of Pt-based ternary alloy nanocrystals, the electro-catalytic performances of Pt-based catalysts can be improved effectively. In this paper, a one-pot method for synthesis of PtCuFe nanoframes (PtCuFe NFs) with tunable structure and defect density is reported. By controlling the heating mode and the type of ligand, then changing the nucleation/growth kinetics, two types of PtCuFe NFs were obtained. These types of catalysts exhibited excellent electro-catalytic performance for methanol electrooxidation (MOR) and formic acid electrooxidation (FAOR). Specifically, the dendritic nanoframes (d-NFs) showed high electro-catalytic activity for MOR and FAOR, which were 8.34 times and 3.68 times higher than commercial Pt/C, respectively. The stability was also greatly improved. The excellent electrocatalytic activity of PtCuFe NFs is attributed to the defect sites of high-index facets and open framework structures. This strategy provides a new idea for improving the electrocatalytic performance of Pt-based catalysts.

Electro-exfoliated PdTe2 nanosheets for enhanced methanol electrooxidation performance in alkaline media

Electrochemical cathodic exfoliation method to obtain PdTe2 nanosheets with [001] preferential orientation and superior alkaline methanol oxidation performance.

Alternative Aqueous Phase Synthesis of a PtRu/C Electrocatalyst for Direct Methanol Fuel Cells

Carbon-supported PtRu nanoalloy (PtRu/C) is widely used as the anode catalyst for direct methanol fuel cells (DMFC), and an aqueous phase synthesis of PtRu/C is in high demand due to for energy-saving and environmentally-benign considerations, however, it is very challenging to attain stoichiometric reduction, good dispersion and a high alloying degree. Herein, we report a facile aqueous phase approach with dimethylamine borane (DMAB) as the reducing agent to synthesize a PtRu/C(DMAB). TEM, XRD, XPS and ICP-AES characterizations indicate that the structural parameters in the PtRu/C(DMAB) are improved significantly as compared to those obtained in a PtRu/C(NaBH4) and a commercial PtRu/C, contributing to an enhanced electrocatalytic performance. It turns out that the PtRu/C(DMAB) exhibits the highest methanol electro-oxidation (MOR) performance among all of the tested samples, with the peak current up to 1.8 times as much as that of the state-of-the-art commercial PtRu/C, corroborating the highest output power density in comparative DMFC tests. In-situ attenuated total reflection infrared (ATR-IR) spectroscopy correlates the higher methanol electro-oxidation performance of the PtRu/C(DMAB) with its enhanced CO resistance and CO2 generation. This simple aqueous synthetic approach may provide an alternative route for developing efficient anode electrocatalysts of DMFCs.

A composite strategy to prepare high active Pt-WO3/MWCNT catalysts for methanol electro-oxidation

Pt-WO3/MWCNTao catalysts with high performance in methanol electro-oxidation were successfully synthesized in this paper. The structure and morphology of the catalysts were characterized by XRD and TEM techniques. The electrochemical activity of the as-prepared catalysts for methanol electro-oxidation was studied by cyclic voltammetry, CO-stripping and chronoamperometry, respectively. The results shown that the mass activity of Pt-WO3/MWCNTao synthesized with two-step was promoted significantly; meanwhile, the CO oxidized potential was lower shift about 50 mV to 0.47 V. The super performance was proposed to be arising from the combination of the usage of high hydrophilic MWCNTs as the supports and employing the synergism effect of WO3 in methanol oxidation. And the nano-composites were proved to be a powerful and effective strategy to obtain anodic catalysts with super activity in direct methanol fuel cell.

Three-dimensional heterogeneous copper cobalt phosphides Nanoflowers for enhancing catalytic performance for electro-oxidation of methanol

BackgroundExploring electrocatalysts with low-cost, high-efficiency and durability for methanol electrocatalytic oxidation reaction is an urgent task. In this study, hydrangea-like CuCoPx (Cu3P/CoP/CoP2) assembled by nanosheets were prepared as a non-noble metal electrocatalyst. MethodsThe hydrangea-like CuCoPx nanoflowers were characterized by the powder X-ray diffraction (XRD), the scanning electron microscopy (SEM) and X-ray photoelectron spectra (XPS). Using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy, the electrocatalytic activity, stability and durability of the catalyst were investigated. Significant FindingsThe results demonstrate that the CuCoPx nanoflowers show high mass activity (287.4 mA mg−1) for methanol oxidation, which is 1.5 times higher than that of CoP. The prolong Cyclic voltammograms scanning (500 cycles) and chronoamperometry verify good stability and durability of CuCoPx in alkaline solution. The excellent electrocatalytic activity of CuCoPx is ascribed to synergistic effect of multicomponent and large specific surface area. This study may provide a new idea for transition metal phosphides for MOR.

Synthesis of MCM‐41 mesoporous silica nanoparticles supported titanium dioxide‐silver nanocomposite with excellent methanol electrooxidation performance

AbstractConsidering the importance of the fuel cells, we developed an appropriate and efficient electrode system for electrocatalytic oxidation of methanol by fabricating the electrode with naturally based synthesized mobil composition of matter No. 41 (MCM‐41) mesoporous silica nanoparticle along with silver and titanium dioxide nanoparticles. The extracted silica from natural stem straw was applied in the synthesis of MCM‐41 mesoporous silica nanoparticle and characterization of the products was performed by different techniques. Then, the synthesized MCM‐41 mesoporous silica is modified by silver and titanium dioxide nanoparticles and is employed in the fabrication of the modified carbon paste electrodes (Ag/TiO2/MCM‐41/CPE) that are accordingly used in the electrocatalytic oxidation of methanol. The mechanistic and kinetic studies of the reactions are thoroughly examined based on cyclic voltammetry and chronoamperometry techniques. The results reveal that the modified carbon paste electrode with silver and titanium dioxide nanoparticles supported onto MCM‐41 mesoporous silica exhibit much higher current densities and less overpotentials than that at the bare carbon paste electrode. The results of the electrocatalytic oxidation of methanol are then compared to the literature indicating that the developed system is favorable for the direct methanol fuel cells.

Worm-like PtCux alloys oriented by pyrolyzed alginic acid sodium with high performance in methanol electrooxidation

Worm-like PtCux alloys were synthesized through the co-reduction of H2PtCl6 and CuCl2 in ethylene glycol under the orientation of pyrolyzed alginic acid sodium (PA), in order to disclose the growth mechanism of different metallic compounds. Through the characterizations of FTIR, Raman, XRD, XPS, TEM, etc., it illustrates that with the orientation of oxygen-containing functional groups in the support PA, the preferentially reduced Pt clusters accelerate the formation of metallic Cu clusters and then worm-like bimetallic PtCux alloys are generated with plenty of surface defects. The synthesized PtCu3/PA exhibits the highest content of metallic Pt0 (67.11 at%), the average width about 2.19 nm, the lattice strain of −1.18%, as well as the excellent performance for methanol electrooxidation. It has the best CO tolerance ability and the optimal mass activity of 1.922 A mgPt−1, which is more than four times of the commercial Pt/C. This work discloses an intriguing growth pathway of PtCux nanoparticles but also a facile route to synthesize bimetallic alloys with more electrocatalytic activity.

Efficient synergism of V2O5 and Pd for alkaline methanol electrooxidation.

Efficient synergism of high valence state V and Pd nanoparticles imparted their high catalytic performance and anti-poisoning ability for alkaline methanol electrooxidation.

Multi-porous NiAg-doped Pd alloy nanoparticles immobilized on reduced graphene oxide/CoMoO4 composites as a highly active electrocatalyst for direct alcohol fuel cell

A self-assembled reduced graphene oxide (rGO)/CoMoO4 supported Pd, PdNi, PdAg and PdNiAg electrocatalysts were synthesized via hydrothermal and in situ impregnation-reduction method to investigate their performance for methanol, ethanol and ethylene glycol (EG) electrooxidation in alkaline media. XRD, TEM, SEM, EDS, XPS and BET were used to characterize the structure, surface features, and porosity of the catalysts, respectively. Electrochemical measurement revealed that tri-metallic PdNiAg@rGO/CoMoO4 catalyst displays outstanding electrocatalytic activity, toxicity resistance, and durability comparing to mono-metallic Pd and bi-metallic PdNi, PdAg counterparts and commercial Pd/C. The excellent electrocatalytic activity has been successfully achieved thanks to NiAg-doped Pd alloy nanoparticles (NPs) owning more surface-active centers and strong synergistic effects, and the host of GO/CoMoO4 providing superior electron transfer performance and multi-porous for the ternary catalyst. Further electrocatalysis mechanism of three kinds of alcohol oxidation drew up a detailed analysis. The design, preparation, and prominent performance of these novel composites offer a conception and promising potential for application of electrocatalyst in direct alcohol fuel cells.

Preparation of platinum-silver alloy nanoparticles and their catalytic performance in methanol electro-oxidation

Platinum-silver alloy nanoparticles (PtxAgy NPs) were synthesized in a molten salt system without using any organic surfactants or solvents; the catalytic role of Ag in the methanol electrooxidation reaction (MOR) in alkaline electrolyte over PtxAgy NPs was investigated. The TEM images suggest that Pt52Ag48 nanotubes (NTs) can be obtained when the Pt/Ag ratio in the molten salt precursor reaches 1. The methanol electrooxidation reaction test results indicate that the Pt52Ag48 NTs with a clean surface exhibits a much better catalytic performance than the conventional Pt black in MOR. Meanwhile, the catalytic activity of the Pt52Ag48 NTs is greatly related to the positive potential limit; the peak current of MOR reaches 1.61 mA/μgPt with a positive potential limit from –1.0 to 0.5 V (vs. SCE), which is 1.92 times higher than that with a positive potential limit from –1.0 to 0.1 V (vs. SCE). The Ag element in the surface layer of PtxAgy alloy may promote the MOR through a redox process during the electrochemical cycle. The insight shown in work should be beneficial to the application of PtxAgy alloy in the direct methanol fuel cells (DMFCs).

Design of 3D Hollow Porous Heterogeneous Nickel-Cobalt Phosphides for Synergistically Enhancing Catalytic Performance for Electrooxidation of Methanol.

The synergistic effect among different components and the structural and morphological control of catalytic nanomaterials have attracted considerable research interest in the field of electrocatalysis, as using a rational design of the catalytic nanomaterials with the desired structure, morphology, and chemical compositions is an effective strategy for enhancing catalytic performance. Here, by changing the Ni/Co atomic ratio of raw materials, a series of samples with a three-dimensional (3D) hollow porous ternary multicomponent heterostructure has been successfully synthesized via a facile template-free solvothermal approach and subsequently annealing and phosphating treatments, and its formation mechanism is also investigated. By virtue of compositional and structural advantages, the optimized Ni1Co2Px (NiCoP/CoP/CoP2) nanoparticles show very high mass activity (436.9 mA mg-1) and area-specific activity (155 mA cm-2), as well as remarkable durability toward the methanol electrooxidation reaction (MOR) in alkaline solution. This catalytic activity is better than those of most of reported Ni/Co-based nonprecious metal catalysts. Particularly, a multicomponent synergistic effect on the MOR was observed. The present study not only provides a simple method for the fabrication of 3D hollow porous multicomponent composite nanomaterials, but also gives insights into the synergistic effect among the porous structure, chemical compositions, and catalytic activity of nanomaterials in the electrocatalytic oxidation of methanol.

Nanocomposite integrating tube-like NiCo2S4 and carbon nanotubes for electrooxidation of methanol

An effective and simple strategy for fabricating a NiCo2S4/CNT nanocomposite by combining carbon nanotubes (CNTs) with tube-like NiCo2S4 is proposed, with the aim of producing a successful catalyst for the electrooxidation of methanol. Tube-like NiCo2S4 was successfully synthesized through a hydrothermal sulfurization process. The carbon nanotubes have high conductivity and provide conductive contact with the tube-like NiCo2S4, making the composite an excellent choice of electrode material for direct methanol fuel cells (DMFC). Field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were used to characterize and investigate the morphological and physicochemical properties of the nanocomposite. The results of these studies helped in evaluating the electrocatalytic behavior of the material and exploring its potential for use in DMFC. Electrocatalytic behavior towards methanol oxidation was studied by electrochemical methods (cyclic voltammetry (CV) and chronoamperometry (CA)), which show that the tube-like NiCo2S4/CNT nanocomposite exhibits excellent electrocatalytic performance for electrooxidation of methanol in an alkaline medium, with a high current density (~160 mA cm−2) and excellent stability (~83% retention after 500 CV cycles). The results presented here clearly indicate that the proposed tube-like NiCo2S4/CNT nanocomposite has potential for applications in DMFCs.

Highly Active Pt-Co/C Nanoparticles: Controllable Preparation and Catalytic Performance for Methanol Electro-oxidation

Highly Active Pt-Co/C Nanoparticles: Controllable Preparation and Catalytic Performance for Methanol Electro-oxidation