Multiphase sodium titanate/titania composite nanostructures as Pt-based catalyst supports for methanol oxidation

Abstract

Sodium titanate/titania composite nanotubes/nanorods (STNS) are synthesized from anatase titania by the hydrothermal method and subsequent annealing in the range of 300-700 C. The changes in the composition and morphology of STNS are investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results reveal that the composition of STNS changes from "Na 2Àx H x Ti 2 O 5 " to "Na 2 Ti 6 O 13 " and their morphology changes from nanotubes to nanorods. The products obtained at 400 C and 600 C correspond to the intermediate state of reactions. Pt-based catalysts are prepared by a microwave-assisted ethylene glycol process, and are also characterized by physical analysis and electrochemical measurements. The variations of the catalytic activity and stability of Pt/C-STNS catalysts show the interesting "M" shape with the increase of the annealing temperature of STNS. The Pt nanoparticles supported on STNS-400 nanotubes and STNS-600 nanorods exhibit more uniform dispersion and superior electrocatalytic performance for methanol electrooxidation. The main reason seems to be that both of them are multiphase composites with a large number of phase interfaces and crystal defects, which is conducive to the deposition of Pt nanoparticles. The uniform dispersion of Pt nanoparticles plays an essential role in the electrochemical performance of catalysts. In addition, the presence of the "anatase TiO 2 " phase in both of them can further enhance the electrochemical performance due to the metal-support interaction. Moreover, compared to commercial Pt/C, the Pt/C-STNS-600 catalyst exhibits higher electrochemical activity and stability, suggesting that superior catalysts can be developed by designing the structure and composition of the supports.

Pt Supported on Carbon‐coating Antimony Tin Oxide as Anode Catalyst for Direct Methanol Fuel Cell

“…The microwave assisted ethylene glycol method was used to deposit the platinum nanoparticles onto the ATO‐C . 40mg ATO‐C was mixed with 48 mL ethylene glycol and 12 mL isopropanol.…”

Superior methanol electrooxidation activity and CO tolerance of mesoporous helical nanospindle-like CeO2modified Pt/C

“…5a, the same pattern appears and the semicircle of Pt@Heli-CeO 2 /C is much smaller than Pt@Octa-CeO 2 /C and Pt/C, reecting that the impedance of the helical ceria modied Pt@Heli-CeO 2 /C is reduced signicantly compared with the octahedron ceria modied Pt@Octa-CeO 2 /C and Pt/C. 33,34 This remarkable enhancement in the electron transmission may be attributed to the helical structure, which is more conductive with better electron transfer than that of the corresponding octahedral structures. 35,36 The electrochemical surface characteristics of Pt@Heli-CeO 2 /C are compared with Pt@Octa-CeO 2 /C and Pt/C catalysts using cyclic voltammetry (Fig.…”

One‐Step Interfacial Functionalization and Synthesis of Mo–Modified TiO2 Nanocrystalline as Composite PtRu Anode Catalyst Support for DMFCs

“…Moreover, the peak potential of oxidation of CO ads on PtRu/iMTNCs−C catalyst exhibits negative shift of 200 mV compared to that of PtRu/C catalyst and the obvious negative shifting of 194 mV in onset potential of CO ads oxidation with PtRu/iMTNCs−C is detected comparing to that with PtRu/C, while the negative shifting in onset potential of CO ads oxidation with PtRu/TNCs−C is only 57 mV comparing to that with PtRu/C, which illustrated the key effects of Mo interfacial functionalization on the improvements of anti‐toxic ability with PtRu/iMTNCs−C. This negative shift in onset and peak potential of CO ads oxidation is considered to be generated from a modification in band structure of supported PtRu NPs, a down shift in d‐band center, resulting from the electron donation from Mo functionalized interface to catalytic metal NPs ,, , …”