Highly effective IrxSn1−xO2 electrocatalysts for oxygen evolution reaction in the solid polymer electrolyte water electrolyser

Abstract

We developed an advanced surfactant-assistant method for the Ir(x)Sn(1-x)O(2) (0 < x ≤ 1) nanoparticle (NP) preparation, and examined the OER performances by a series of half-cell and full-cell tests. In contrast to the commercial Ir black, the collective data confirmed the outstanding activity and stability of the fabricated Ir(x)Sn(1-x)O(2) (x = 1, 0.67 and 0.52) NPs, which could be ascribed to the amorphous structure, good dispersion, high pore volume, solid-solution state and Ir-rich surface for bi-metal oxides, and relatively large size (10-11 nm), while Ir(0.31)Sn(0.69) exhibited poor electro-catalytic activity because of the separated two phases, a SnO(2)-rich phase and an IrO(2)-rich phase. Furthermore, compared with highly active IrO(2), the improved durability, precious-metal Ir utilization efficiency and correspondingly reduced Ir loading were realized by the addition of Sn component. When the Ir(0.52)Sn(0.48)O(2) cell operated at 80 °C using Nafion® 115 membrane and less than 0.8 mg cm(-2) of the noble-metal Ir loading, the cell voltages we achieved were 1.631 V at 1000 mA cm(-2), and 1.821 V at 2000 mA cm(-2). The IR-free voltage at the studied current density was very close to the onset voltage of oxygen evolution. The only 50 μV h(-1) of voltage increased for the 500 h durability test at 500 mA cm(-2). In fact, these results are exceptional compared to the performances for OER in SPEWE cells known so far. This work highlights the potential of using highly active and stable IrO(2)-SnO(2) amorphous NPs to enhance the electrolysis efficiency, reduce the noble-metal Ir loading and thus the cost of hydrogen production from the solid polymer electrolyte water electrolysis.

Iridium As Catalyst and Cocatalyst for Oxygen Evolution/Reduction in Acidic Polymer Electrolyte Membrane Electrolyzers and Fuel Cells

“…129 The Ir nanodendrites are well dispersed and their mean size (15 nm, Figure 12a) is considerably smaller than that of Ir blacks (inset of Figure 12d). The TEM image in Figure 12b shows the dendritic nanostructure of Ir 67 @Pt 33 . The lattice fringes in the HRTEM image (inset in Figure 12b) indicate good crystallinity of the Ir 67 @Pt 33 .…”

The Stability Challenges of Oxygen Evolving Catalysts: Towards a Common Fundamental Understanding and Mitigation of Catalyst Degradation

“…Example of an EDX scan of an Ir 0.69 Sn 0.31 O 2 catalyst on carbon; [110] reprinted with permission from the RSC. [110] reprinted with permission from the RSC. Angewandte Chemie Reviews…”

Effect of Adding CeO2 to RuO2–IrO2 Mixed Nanocatalysts: Activity towards the Oxygen Evolution Reaction and Stability in Acidic Media

“…[26][27][28][29][30] This procedure permitted us to evaluate catalyst ageingd uring al ong-term test. One thousand cycles were applied to the electrode materials between0 .3 and 1.2 Vv ersus RHE in 0.5 mol L À1 H 2 SO 4 at 20 mV s À1 to observe the evolution of the current.…”