Electrodeposited Tl2 O 3‐Matrix Composites: II. Electrocatalysis of Oxygen Evolution Reaction on Composites

Abstract

The dependence of composition and morphology of Tl203/Co304 composites on the experimental variables chosen for their anodic deposition (i.e., concentration of Co304 particles in suspension, electrode potential, electrolysis charge, and angular speed of the electrode) has been investigated. The composite layers have been tested as electrode materials for oxygen evolution from basic media, and found to be rather effective electrocatalysts characterized by the following features: overpotential (ii) at j = 100 mA cm2 ca. 475 mV, Tafel slope close to 60 mV decade, linear dependence of j on [OW]. Significant electrocatalytic activity could be achieved with a Co304 loading as low as 2 iO g cm2. The electrode performance was maintained during a 14 day electrolysis carried out at room temperature with j = 100 mA cm2. Partial reduction of the composite layer was found to activate the composite electrodes, by decreasing i' to ca. 415 mV (at j = 100 mA cm2). However this activation was not long lasting.

Electrodeposited lead dioxide coatings

“…Musiani's group [143][144][145][146][147][148][149][150][151][152][153][154] have sought to produce new electrocatalysts for the oxygen evolution reaction and other electrochemical oxidation processes essentially using the PbO 2 as a stable, conducting matrix to encapsulate particles that are more active catalysts for O 2 evolution and other reactions. They have studied composites with both electrocatalytic and inactive particulates and some particulates also enhanced the conductivity and/or mechanical strength of the PbO 2 matrix.…”

Electrosynthesis of nanocomposite materials for electrocatalysis

“…Similarly, Tl 2 O 3 + Co 3 O 4 composites were much rougher than Tl 2 O 3 [30]. Instead, co-deposition of inert particles like TiO 2 or Al 2 O 3 did not affect PbO 2 roughness in a significant way [37].…”

“…SEM and X-ray diffraction (for experimental details see refs. [28][29][30][31][32][33][34][35][36][37]39]) were used to study morphology and texture of the deposits.…”

“…The stability of composite electrodes under oxygen evolution conditions was tested by prolonged galvanostatic electrolyses; PbO 2 + Co 3 O 4 and Tl 2 O 3 + Co 3 O 4 were used in basic media [28,30], PbO 2 -matrix composites containing RuO 2 or mixed Ru oxides in H 2 SO 4 solution [33,34]. It is to note that acids forming water-soluble Pb salts could not be used instead of H 2 SO 4 since, at open circuit, the simultaneous occurrence of oxygen evolution and PbO 2 reduction led to complete corrosion of the PbO 2 + RuO 2 composites.…”

“…in the hydrogen evolution or oxygen evolution reactions (henceforth her and oer, respectively), the generation of bubbles inside a polymer matrix induces its mechanical deformation, rupture and detachment from the underlying material. Thus, it is not surprising that polymer-matrix composites have been tested for oxidation of molecular hydrogen [1][2][3][4][5][6] or reduction of molecular oxygen [3,[7][8][9][10][11][12][13][14][15], while metal-matrix and oxide-matrix composites have been studied as electrode materials for her [16][17][18][19][20][21][22][23][24][25] and oer [26][27][28][29][30][31][32][33][34][35][36].…”