Tuning Pt–Ir Interactions for NH₃ Electrocatalysis

Abstract

Pt x Ir100–x thin films (8 nm thick) were deposited on MgO(100) substrates by pulsed laser deposition at 600 °C. As shown by X-ray diffraction and X-ray photoelectron spectroscopy analyses, the formation of fcc bulk and surface PtIr solid solution was observed over the whole compositional range despite the large miscibility gap exhibited by these elements below ca. 1000 °C. Moreover, pole figures indicate that all films exhibit a Pt(001)[010]//[010](001)­MgO cube-on-cube epitaxial relationship, which is consistent with AFM images. Cyclic voltammetry measurements performed in alkaline solutions confirmed both the presence of Ir atoms at the surface and the (100) surface orientation of all Pt x Ir100–x surfaces. The highest electrocatalytic activity for the electrooxidation of NH3 was observed for the Pt74Ir26(100) surface with a current density of ca. 1.0 mA cm–2 at 0.71 V vs RHE, which is 25% higher than that on Pt(100). The reasons underlying this behavior are discussed.

Ir‐Au Bimetallic Nanoparticle Modified Silicon Nanowires with Ultralow Content of Ir for Hydrogen Evolution Reaction

“…Ir 4f 5/2 and 4f 7/2 peaks ( Figure 1c) are at 63.7 and 60.7 eV. [20] Au 4f 5/2 and 4f 7/2 peaks are at 87.7 and 84.0 eV ( Figure 1d). [21] Both peaks of Ir and Au show that the nanoparticles are metallic without oxidation.…”

“…When the H‐terminated SiNWs are exposed to the air, the surfaces are oxidized again. Ir 4f 5/2 and 4f 7/2 peaks (Figure c) are at 63.7 and 60.7 eV . Au 4f 5/2 and 4f 7/2 peaks are at 87.7 and 84.0 eV (Figure d) .…”

Hydrogen generation from ammonia electrolysis on bifunctional platinum nanocubes electrocatalysts

“…+ 2NH 3 (aq) → 6H 2 O + N 2 (g) + 6e − , ϕ 0 = −0.77 V] in alkaline media is an important electrochemical half-reaction for industrial wastewater treatment for ammonia removal, direct ammonia fuel cells and ammonia electrolysis [1][2][3][4] . Among them, ammonia electrolysis is attracting increased attention, which is considered as an environmentally friendly and efficient ultra-pure hydrogen (H 2 ) generation method [5][6][7][8][9] .…”

Making an ultralow platinum content bimetallic catalyst on carbon fibres for electro-oxidation of ammonia in wastewater

“…21 Pt-free or Pt-alloyed electrodes based on iridium, ruthenium, rhodium, and palladium metals have also been studied. 12,[22][23][24][25][26][27][28][29][30] These electrodes may perform better than pure Pt electrodes in the electro-oxidation of ammonia, but the preparation costs are even greater. A combination of the two approaches, using small amounts of expensive Pt while alloying more inexpensive compounds on high surface-to-volume support substrates has received less attention.…”