Ultrathin IrO₂ Nanoneedles for Electrochemical Water Oxidation

Abstract

Electrochemical water splitting is promising for utilizing intermittent renewable energy. The sluggish kinetics of the oxygen evolution reaction (OER), however, is a bottleneck in obtaining high efficiency. Only a few OER electrocatalysts have been developed for the use in acidic media despite the importance of a proton exchange membrane (PEM) water electrolyzer. IrO 2 is the only material that is both active and stable for the OER in highly corrosive acidic conditions. Herein, a facile and scalable synthesis of ultrathin IrO 2 nanoneedles is reported with a diameter of 2 nm using a modified molten salt method. The activity and durability for the OER are significantly enhanced on the ultrathin IrO 2 nanoneedles, compared to conventional nanoparticles. The ultrathin nanoneedles are successfully introduced to a PEM electrolyzer single cell with the enhanced cell performance.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.

Low‐Coordinate Iridium Oxide Confined on Graphitic Carbon Nitride for Highly Efficient Oxygen Evolution

“…As shown in Figure 1b,t ypical diffraction peaks of rutile IrO 2 (JCPDS 15-0870) and GCN (JCPDS 87-1526) are present in the XRD patterns of IrO 2 /GCN containing 40 wt % IrO 2 (40-IG). [8] Therelative density of the diffraction peak at 28.08 8 of 40-IG increases significantly compared with IrO 2 owing to the merging of the GCN peak at 27.88 8.T he Fourier-transform infrared spectroscopy (FTIR) further confirms the presence of GCN in 40-IG (Supporting Information, Figure S2). [9] Thet ransmission electron microscopy (TEM) images (Figure 1c,d) illustrate that IrO 2 NPs are well dispersed on GCN nanosheets.A sr evealed by the HRTEM (Figure 1e)a nd the fast Fourier transform patterns (FFT, Figure 1f), the lattice spacing of 0.26 and 0.31 nm can be assigned to the (101) and (110) planes of IrO 2 ,r espectively.…”

BSA‐IrO2: Catalase‐like Nanoparticles with High Photothermal Conversion Efficiency and a High X‐ray Absorption Coefficient for Anti‐inflammation and Antitumor Theranostics

“…X-ray photoelectron spectroscopy (XPS) was used to study the surface state of BSA-IrO 2 NPs.The characteristic peaks at 61.8 and 64.7 eV can be assigned to 4f 7/2 and 4f 5/2 of Ir 4+ ,a nd the deconvolved peaks at 532.6 and 531.0 eV in the highresolution spectrum of O1s are attributed to -COOH (BSA), -C = O( BSA), and Ir À O À Ir bonding,r espectively (see Figure S5), which suggest the formation of IrO 2 . [12] TheU V/Vis spectrum ( Figure 1d)o fB SA-IrO 2 NPs showed ab road absorption over the nearinfrared region with am aximal peak at 598 nm caused by localized surface plasmon resonances (LSPRs) and small-polaron absorption [13] due to the high carrier density of IrO 2 NPs (9.132 10 20 cm À3 ;s ee the Supporting Information) and the presence of oxygen defects (see Figure S7). [12] TheU V/Vis spectrum ( Figure 1d)o fB SA-IrO 2 NPs showed ab road absorption over the nearinfrared region with am aximal peak at 598 nm caused by localized surface plasmon resonances (LSPRs) and small-polaron absorption [13] due to the high carrier density of IrO 2 NPs (9.132 10 20 cm À3 ;s ee the Supporting Information) and the presence of oxygen defects (see Figure S7).…”

Minimization of Catalyst Loading on Regenerative Fuel Cell Positive Electrodes Based on Titanium Felts using Atomic Layer Deposition

“… Comparison of the oxygen evolution performance (in Tafel plot format) in terms of overpotential η and mass activity of our catalyst coated nanostructured electrode (green filled symbols: data obtained from steady‐state electrolysis; green empty symbols: data obtained from cyclic voltammetry) with the state of the art (black symbols): 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 …”