Electroreduction of oxygen at tungsten oxide modified carbon-supported RuSex nanoparticles

Abstract

WO 3 -modified carbon-supported bi-component ruthenium-selenium, RuSe x (Ru, 20; Se, 1 wt%), nanoparticles were dispersed in the form of Nafion-containing inks on glassy carbon electrodes to produce electrocatalytic interfaces reactive towards electroreduction of dioxygen in acid medium (0.5 mol dm -3 H 2 SO 4 ). It was apparent from the rotating disk voltammetric experiments that the reduction of oxygen proceeded at WO 3 -modified electrocatalyst at more than 100 mV more positive potential when compared to bare (WO 3 -free) RuSe x system (that had been prepared under analogous conditions and deposited at the same loading of 156 lg cm -2 ). The ring-disk rotating voltammetric measurements show that, while the production of hydrogen peroxide intermediate was significantly lower, the kinetic parameter (heterogeneous rate constant) for the oxygen reduction was higher for WO 3 -modified RuSe x (relative to bare RuSe x ). Comparison was also made to highly-efficient Vulcan-supported Pt or Pt/Co nanoparticles: while the half-wave potential for the oxygen reduction at WO 3 -modified carbon-supported RuSe x was still more negative relative to the potentials characteristic of Pt-based electrocatalysts, the oxygen reduction rotating disk voltammetric current densities (measured at 1600 rpm) were almost identical.

Evaluation of RuxWySez Catalyst as a Cathode Electrode in a Polymer Electrolyte Membrane Fuel Cell

“…In relation with the series pathway, k 3 is greater than k 2 suggesting that the amount of H 2 O 2 generated was reduced to H 2 O as soon as H 2 O 2 is produced. A similar behaviour was observed on metallic and bimetallic chalcogenide cluster catalysts [23][24][25], where the high value of the ratio k 1 /k 2 was explained in terms of a non-negligible depletion of the oxygen concentration at the electrode interface which may produce a decrease of the hydrogen peroxide concentration, conducing to an almost potential-independent value of k 3 . From the kinetic results we tested the Ru x W y Se z electrocatalysts as cathode in a single fuel cell.…”

Oxygen reduction reaction increased tolerance and fuel cell performance of Pt and RuxSey onto oxide–carbon composites

“…Chemical modification of carbon nanotubes [1][2][3] or nanostructured carbon [4][5][6][7][8][9][10][11][12] has been undertaken. Another strategy to stabilize the support is to develop metal-oxide substrates as reported for SiO 2 [13], NbO 2 [14], MnO x [15], WO x [16,17], SnO 2 [18] and TiO x [15,[19][20][21][22][23][24][25][26][27][28]. Pt deposited on such substrates shows an increase of the activity for the oxygen reduction reaction (ORR) as compared to Pt/C.…”

“…Such chalcogenide catalyst has a comparable activity to Pt catalyst and a good performance for the ORR even at high concentrations of fuel. Ru x Se y particles were also deposited onto metal-oxide substrates and showed an enhancement of the ORR activity [16,25]. Other catalyst materials such as transition metal chalcogenides: Pt x S y and Co x Se y demonstrated to be methanol tolerant [44][45][46] and selective to the oxygen reduction reaction (ORR).…”

Oxalate supported pyrolysis of CoTMPP as electrocatalysts for the oxygen reduction reaction

“…Beside platinum alloys [1] and chalcogenides systems, like RuSe x , RuS x and RhS x [2][3][4][5], research has been focused on transition metal-based Me-N 4 macrocycles. Progress for this catalyst class has been made through the work of Jahnke et al [6], who improved the activity and stability of the Me-N 4 macrocycles by a heat treatment (500-900 • C) in an inert atmosphere.…”