Electrocatalytic activity of IrO2–RuO2 supported on Sb-doped SnO2 nanoparticles

Abstract

Electrocatalytic IrO 2 -RuO 2 supported on Sb-doped SnO 2 (ATO) nanoparticles is very active towards the oxygen evolution reaction. The IrO 2 -RuO 2 material is XRD amorphous and exists as clusters on the surface of the ATO.Systematic changes to the surface chemical composition of the ATO as a function of the IrO 2 :RuO 2 ratio suggests an interaction between the IrO 2 -RuO 2 and ATO. Cyclic voltammetry indicates that the electrochemically active surface area of IrO 2 -RuO 2 clusters is maximised when the composition is 75 mol% IrO 2 -25 mol% RuO 2 . Decreasing the loading of IrO 2 -RuO 2 on ATO reduces the electrochemically active surface area, although there is evidence to support a decrease in the clusters size with decreased loading. Tafel slope analysis shows that if the clusters are too small, the kinetics of the oxygen evolution reaction are reduced. Overall, clusters of IrO 2 -RuO 2 on ATO have similar or better performance for the oxygen evolution reaction than many previously reported materials, despite the low quantity of noble metals used in the electrocatalysts. This suggests that these oxides may be of economic

Importance of trivalency and the e g 1 configuration in the photocatalytic oxidation of water by Mn and Co oxides

“…S1 for an X-ray diffraction pattern and transmission electron microscope (TEM) image], prepared by the citrate sol-gel method from their corresponding metal precursors. Oxygen evolution was studied under visible light in a standard photoexcitation system consisting of Ru(bpy) 3 2+ as the photosensitizer and Na 2 S 2 O 8 as the sacrificial electron acceptor in a solution buffered at pH = 5.8. Oxygen evolved was quantified both by a Clark-type electrode and gas chromatography.…”

“…The gel was prepared with metal:citric acid ratio of 1:10. It was first heated at 200°C for 12 h followed by heating for 5 h in air at 500 and 800°C for LaCoO 3 and LaMnO 3 , respectively. In the case of Mn 2 O 3 , the gel was prepared with Mn(CH 3 COO) 2 :citric acid ratio of 1:2 with the final heating of 500°C for 8 h in air.…”

“…Thus, Mn 2 O 3 , LaMnO 3 , and MgMn 2 O 4 are found to be very good catalysts with turnover frequencies of 5 × 10 −4 s −1 , 4.8 × 10 −4 s −1 , and 0.8 ×10 −4 s −1 , respectively. Among the cobalt oxides, Li 2 Co 2 O 4 and LaCoO 3 -especially the latter-exhibit excellent catalytic activity, with the turnover frequencies being 9 × 10 −4 s −1 and 1.4 × 10 −3 s −1 , respectively.…”

“…One of the challenges with artificial photosynthesis is the development of cost-effective catalysts made of abundant elements for the efficient oxidation of water to O 2 (1). RuO 2 and IrO 2 are widely used as oxygen evolution catalysts although their availability is limited and are expensive (2)(3)(4)(5). Oxidation of water in plants occurs in Photosystem II making use of the Mn 4 O 5 Ca cluster (6, 7) present in the protein.…”

Tantalum carbide as a novel support material for anode electrocatalysts in polymer electrolyte membrane water electrolysers

“…The most common is the Adams fusion method [15], which produces metal oxides [12,16e20]. The other methods used are the polyol method (also known as the colloid method) [16,17,19], simple thermal decomposition of the corresponding metal chlorides [21], and chemical reduction [22]. The polyol method and chemical reduction are usually followed by the oxidation of the resulting metal particles, either anodically or by simple calcination in air.…”