Published April 30, 2015 | Version v1
Journal article Metadata-only

Enhanced methanol electro-oxidation reaction on Pt-CoOx/MWCNTs hybrid electro-catalyst

Creators

  • 1. Catalysis and Nanotechnology Research Division, Research Institute of Petroleum Industry (RIPI), P.O. Box 14665-1998, Tehran (Iran, Islamic Republic of)
  • 2. Caspian Faculty of Engineering, University of Tehran, P.O. Box 43841-119, Rezvanshahr (Iran, Islamic Republic of)
  • 3. Catalysis and Nanostructured Materials Research Laboratory, School of Chemical Engineering, University of Tehran, P.O. Box 11155/4563, Tehran (Iran, Islamic Republic of)

Description

Highlights: • Promoting effects of Cobalt oxide on methanol electro-oxidation over Pt/MWCNTs are investigated. • Higher activity, about 2.9 times, and enhanced stability are observed on Pt-CoOx/MWCNTs. • Electrochemical active surface area of Pt nanoparticles is significantly improved upon CoOx addition. • Bi-functional mechanism is facilitated in presence of CoOx. - Abstract: The electro-catalytic behavior of Pt-CoOx/MWCNTs in methanol electro-oxidation reaction (MOR) is investigated and compared to that of Pt/MWCNTs. The electro-catalysts were synthesized by an impregnation method using NaBH4 as the reducing agent. The morphological and physical characteristics of samples are examined by XRD, TEM, ICP and EDS techniques. In the presence of CoOx, Pt nanoparticles were highly distributed on the support with an average particle size of 2 nm, an obvious decrease from 5.1 nm for Pt/MWCNTs. Cyclic voltammetry, CO-stripping, Chronoamperometry, and electrochemical impedance spectroscopy (EIS) measurements are used to study the electrochemical behavior of the electro-catalysts. The results revealed a considerable enhancement in the oxidation kinetics of COads on Pt active sites by the participation of CoOx. Compared to Pt/MWCNTs, Pt-CoOx/MWCNTs sample has a larger electrochemical active surface area (ECSA) and higher electro-catalytic activity and stability toward methanol electro-oxidation. According to the results of cyclic voltammetry, the forward anodic peak current density enhances more than 89% at the optimum atomic ratio of Pt:Co = 2:1. Furthermore, inclusion of cobalt oxide species causes the onset potential of methanol electro-oxidation reaction to shift 84 mV to negative values compared to that on Pt/MWCNTs. Based on EIS data, dehydrogenation of methanol is the rate-determining step of MOR on both Pt/MWCNTs and Pt-CoOx/MWCNTs, at small overpotentials. However, at higher overpotentials, the oxidation of adsorbed oxygen-containing groups controls the total rate of MOR process

Availability note (English)

Available from http://dx.doi.org/10.1016/j.apsusc.2015.02.011

Additional details

Identifiers

DOI
10.1016/j.apsusc.2015.02.011;
PII
S0169-4332(15)00306-2;

Publishing Information

Journal Title
Applied Surface Science
Journal Volume
335
Journal Page Range
p. 55-64
ISSN
0169-4332
CODEN
ASUSEE

INIS

Country of Publication
Netherlands
Country of Input or Organization
International Atomic Energy Agency (IAEA)
INIS RN
47037619
Subject category
S77: NANOSCIENCE AND NANOTECHNOLOGY;
Descriptors DEI
AMPEROMETRY; CARBON MONOXIDE; CARBON NANOTUBES; COBALT OXIDES; CURRENT DENSITY; DEHYDROGENATION; ELECTROCATALYSTS; ELECTROCHEMISTRY; METHANOL; NANOPARTICLES; NANOSTRUCTURES; OXIDATION; PARTICLE SIZE; PLATINUM; SPECTROSCOPY; STABILITY; SURFACE AREA; TRANSMISSION ELECTRON MICROSCOPY; VOLTAMETRY; X-RAY DIFFRACTION
Descriptors DEC
ALCOHOLS; CARBON; CARBON COMPOUNDS; CARBON OXIDES; CATALYSTS; CHALCOGENIDES; CHEMICAL ANALYSIS; CHEMICAL REACTIONS; CHEMISTRY; COBALT COMPOUNDS; COHERENT SCATTERING; DIFFRACTION; ELECTRON MICROSCOPY; ELEMENTS; HYDROXY COMPOUNDS; METALS; MICROSCOPY; NANOSTRUCTURES; NANOTUBES; NONMETALS; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; PARTICLES; PLATINUM METALS; QUANTITATIVE CHEMICAL ANALYSIS; SCATTERING; SIZE; SURFACE PROPERTIES; TITRATION; TRANSITION ELEMENT COMPOUNDS; TRANSITION ELEMENTS; VOLUMETRIC ANALYSIS

Optional Information

Copyright
Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.