Pt For Methanol Electrooxidation Research Articles

Multi-dimensional Pt/Ni(OH)2/nitrogen-doped graphene nanocomposites with low platinum content for methanol oxidation reaction with highly catalytic performance

Direct methanol fuel cell has been widely recognized as the ideal renewable energy conversion device. However, it still suffers from two major limitations: the heavy use of precious metal platinum and the sluggish kinetics of methanol oxidation catalytic reaction, which have prevented its large-scale commercialization. Therefore, it is considered desirable to design rational and greatly effective catalysts. In this work, multi-dimensional ternary composite electrocatalysts of Pt/Ni(OH)2/nitrogen-doped graphene catalysts have been synthesized with 0D Pt nanoparticles on the 2D Ni(OH)2 nanosheets supported by 3D porous nitrogen-doped graphene hydrogel, and with a low amount (4.26 wt%) of Pt. Notably, the multi-dimensional porous structure design, abundant hydroxyl species, and mutual interactions of ternary catalysts endow high activity promoting the poisonous CO or CO-like intermediates oxidation and propelling the kinetics of sluggish MOR. These novel Pt/Ni(OH)2/NG catalysts exhibit an excellent mass activity of 2.99 A mg−1Pt for methanol electrooxidation, which is about 2.8 and 4.8 times higher than those of commercial PtRu/C and Pt/C, respectively. Furthermore, both durability and CO tolerance of Pt/Ni(OH)2/NGs electrocatalysts are significantly improved.

MOF-derived Co embedded into N-doped nanotube decorated mesoporous carbon as a robust support of Pt catalyst for methanol electrooxidation

The fabrication of a Pt-based catalyst with high activity and stability for methanol electrooxidation is both of vital importance and challenging for direct methanol fuel cells. Herein, a catalyst support based on Co embedded into N-doped nanotube decorated mesoporous carbon (Co@NCNTs-MC) derived from metal-organic frameworks (MOFs) was synthesized by a pyrolysis method at an appropriate temperature and duration using ZIF-67 as a precursor, and melamine as an additional nitrogen source. The presence of melamine ensures adequate nitrogen content at high temperature, promotes the formation of NCNTs through the help of Co nanoparticles in the pyrolysis process and forms a mesoporous carbon structure. The optimum pyrolysis condition was found to be 800 °C for 4 h. A Pt-based catalyst was synthesized with the as-prepared Co@NCNTs-MC support which was found to significantly improve the dispersion of Pt nanoparticles and enhance the transportation of electrons and mass. Co-Nx bonds are shown to provide an abundance of active sites. A Pt/Co@NCNTs-MC800-4 sample is found to show mass activities of 700.3 mA mg−1Pt for methanol electrooxidation, which is approximately 4.5 times higher than that of 20% Pt/C. This work brings new opportunities to design and prepare promising catalyst supports for direct methanol fuel cells.

Nitrogen doped carbon coated Mo modified TiO2 nanowires (NC@MTNWs-FI) with functionalized interfacial as advanced PtRu catalyst support for methanol electrooxidation

A strategy combining hydrothermal in-situ pre-carbonization coating and interfacial functionalization is proposed to prepare the nitrogen doped carbon coated Mo modified one-dimensional TiO2 nanowires (NC@MTNWs-FI) with functionalized interfacial core-shell structure as advanced carriers for PtRu nanoparticles towards methanol electrooxidation. Mo functional doping and chitosan pre-carbonization occur simultaneously on the surface of TiO2 nanowires (TNWs), resulting in a special concentric multilayer one-dimensional (1D) structure with TiO2 core, Mo functionalized interface and an outer N-doped carbon layer. The mass activity of the prepared PtRu/NC@MTNWs-FI catalyst is increased to 1.23 A mg−1 Pt for methanol electrooxidation, which is 2 times higher than that of the unmodified supported catalyst (PtRu/NC@TNWs) and the stability is increased by 15.9%. In addition, it is 2.24 times higher than that of the PtRu/C catalyst and the stability is increased by 23.2%. This excellent catalytic performance is attributed to the synergistic electron donating effect of the Mo functionalized interface and the nitrogen doped carbon layer on the supported PtRu as well as the stronger anchoring effect. This work reveals a new method for designing highly active and stable electrocatalytic support materials for the development of fuel cells.

Worm-like PtP nanocrystals supported on NiCo2Px/C composites for enhanced methanol electrooxidation performance

Worm-like PtP nanocrystals supported on NiCo2Px/carbon black (NiCo2Px/C) composites were prepared by a combined hydrothermal, low temperature phosphidation and NaBH4 reduction process. Noteworthily, the presence and content of phosphorus (P) play a critical role in constructing one-dimensional (1D) PtP nanostructures. Electrochemical tests demonstrate that the obtained PtP-NiCo2Px/C hybrid exhibits an extremely high mass activity of 1361 mA mg−1Pt for methanol electrooxidation in acidic medium, which is 3.5- and 7.6-fold greater than those of commercial Pt/C (393 mA mg−1Pt) and home-made Pt/C catalyst (180 mA mg−1Pt), respectively. Meanwhile, the catalytic performence of PtP-NiCo2Px/C is also better than those of the PtP-CoP/C and PtP-Ni2P/C catalysts due to the synergistic effect of Co and Ni. Furthermore, PtP-NiCo2Px/C catalyst exhibited better durability and CO tolerance compared with other catalysts in this study. The enhanced catalytic performence of PtP-NiCo2Px/C hybrid can be attributed to the special 1D morphology of PtP nanocrystals, the strong interaction between catalytic species and support, as well as the existence of metal center (Mδ+, M = Ni or Co) and Pδ− active sites for the dissociation of H2O molecules. The design of 1D PtP alloy nanostructures and co-catalytic effect of NiCo2Px provides a promising method to significantly improve methanol oxidation performence.

Synergetic Effect of WC/Porous Graphite Carbon Supports on Electrocatalytic Reactivity of Pt for Methanol Electrooxidation

Synergetic Effect of WC/Porous Graphite Carbon Supports on Electrocatalytic Reactivity of Pt for Methanol Electrooxidation

Electrocatalytic enhancement of methanol oxidation by adding CeO2 nanoparticle on porous electrode

The polyaniline/polysulfone (PAN/PSF) composite films were prepared by electropolymerization, and then CeO2-Pt particles were codeposited into this composite film to obtain the CeO2-Pt-modified polyaniline/polysulfone (CeO2-Pt/PAN/PSF) electrodes. Their morphology and chemical component were characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDS), respectively. The results showed that the composite film had bi-layer structure with asymmetrical pores, and platinum and cerium oxide particles were homogeneously dispersed in the modified film electrodes. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were applied to investigate the electrocatalytic activity of the Pt-CeO2/PAN/PSF electrodes. It was indicated that appropriate amount of CeO2 could enhance the catalytic activity of Pt for methanol electro-oxidation. Chronoamperometry (i-t) measurements revealed that the Pt-CeO2/PAN/PSF electrode was relatively endurable for intermediate production. In addition, different mixing amounts of Pt and CeO2 nanoparticles were also investigated in detail.

In situ chemical fabrication of polyaniline/multi-walled carbon nanotubes composites as supports of Pt for methanol electrooxidation

National Natural Science Foundation of China [50873082, 50903066]; Research Fund for the Doctoral Program of Higher Education [20070384047]; Scientific and Technological Innovation Flat of Fujian Province [2009J1009, 2010H6021]

Structural designing of Pt-CeO2/CNTs for methanol electro-oxidation

Abstract In an attempt to utilize CeO2 as a co-catalyst with Pt for methanol electro-oxidation, Pt-CeO2/CNTs were prepared through structural designing by adsorbing Pt nanoparticles on CeO2 coated CNTs. X-ray Diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) were used to analyze the composition of the prepared catalysts. Zeta potential analysis, high resolution transmission electron microscopy (HRTEM) and cyclic voltammetry (CV) methods indicated that Pt nanoparticles are selectively adsorbed on CNTs other than CeO2 surface. Pt-CeO2/CNTs were compared with Pt supported on CNTs in terms of electrochemical active surface (EAS) areas, methanol electro-oxidation activity, and chronoamperometry, results indicating that CeO2 can enhance the catalytic activity of Pt for methanol electro-oxidation with no apparent decrease of EAS. The CO stripping test showed that CeO2 can make CO stripped at a lower potential, which is helpful for CO and methanol electro-oxidation.