Highly active nano-sized iridium catalysts: synthesis and operando spectroscopy in a proton exchange membrane electrolyzer

Abstract

Ultra-high purity nano-sized iridium enclosed in a monolayer of IrIII/IrIV oxides/hydroxides leads to an enhancement in OER activity.

Manipulating the Corrosion Resistance of SnO2 Aerogels through Doping for Efficient and Durable Oxygen Evolution Reaction Electrocatalysis in Acidic Media

“…Note however that, based on the linear dependence of these peak potentials with pH, Kuo et al 39 suggested that these peaks may be ascribed to the transition between surface adsorbed hydroxyl and oxygen. The absence of electrical charge associated with the underpotential deposition of H was another evidence that a stable oxide layer had formed after the electrochemical conditioning stage 30,40 For all materials, we measured OER mass activities approaching 250 A g Ir -1 at 1.51 V vs. RHE (η = 280 mV), and exceeding those of the commercial IrO catalyst (at least times), and those of IrO 2 particles supported onto ATO reported by Lettenmeier et al 41 ,…”

Considerations for the scaling-up of water splitting catalysts

“…While partly due to iridium's rarity, this difference is also a testament to the exceptionally good HER activity of platinum and the limitations that the scaling relations, discussed below, impose on current OER catalysts, including iridium. A comparison between HER activity of platinum and the OER activity for a state-of-the-art iridium-based catalyst 12 ( Figure 1A) underscores this, demonstrating 3-4 orders of magnitude difference.…”

Operando Evidence for a Universal Oxygen Evolution Mechanism on Thermal and Electrochemical Iridium Oxides

“…The contribution of the IrCl3 being small, its observation in the powder diffraction patterns can be attributed to the large size of IrCl3 crystals (see Ref. 9 ). IrO2 sample is fully represented by the rutile phase oxide.…”

“…Fitting of the spectra was performed using five doublets with Ir4f7/2 peak positions at 60.85 eV, 61.70 eV, 63.00 eV, 62.40 eV and 64.20 eV, and attributed to metallic Ir; Ir (IV) and its satellite; Ir (III) and its satellite, correspondingly as it was discussed in our previous publications 2,9 . Ir4f XP spectra recorded on Ir@IrOx anode under different polarizations and 2 photon energies are displayed in Figure S 11 and Figure S 12.…”