Abstract:
The preparation of metal nanoparticles (Pd, Ni, Sn) supported on sulfonated multi-walled carbon
nanotubes (SF-MWCNTs) using a very rapid microwave-assisted solvothermal strategy has been
described. Electrocatalytic behaviour of the SF-MWCNT-Pd and its ‘mixed’ bimetallic electrocatalysts
(i.e., SF-MWCNT-PdSnmix and SF-MWCNT-PdNimix) towards ethanol oxidation in alkaline medium was
investigated. The result shows that the mixed Pd-based catalysts (obtained by simple ultrasonic-mixing
of the individual MWCNT-metal nanocomposites) gave better electrocatalytic activity than their alloy
nanoparticles (obtained by co-reduction of metal salts) or Pd alone. The SF-MWCNT platform gave better
electrocatalytic performance compared to the unsulfonated and commercial Vulcan carbons. Detailed
electrochemical studies (involving cyclic voltammetry, chronoamperometry, chronopotentiometry, and
impedance spectroscopy) prove that the electrocatalytic oxidation of ethanol at the SF-MWCNT-PdNimix
platform is more stable, occurs at lower potential, gives lower Tafel slopes, with faster charge-transfer
kinetics compared to its SF-MWCNT-PdSnmix counterpart. Also, result revealed that SF-MWCNT-PdNimix
is more tolerant to CO poisoning than the SF-MWCNT-PdSnmix. The results provide some important
insights into the electrochemical response of microwave-synthesised Pd-based bimetallic catalysts for
potential application in direct ethanol alkaline fuel cell technology.
