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A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions
Published on: August 17, 2016
Mixed-Valence Atomic-Layer Iridium Patches Enhance Alkaline Hydrogen Evolution
Payam Ahmadian Koudakan1, Xiaobin Hao2, Rui Guo1
1State Key Laboratory of Chemo and Biosensing, College of Chemistry and Chemical Engineering, and National Graduate College for Elite Engineers, Hunan University, Changsha, China.
Abstract:
Engineering structurally defined interfacial motifs between isolated atoms and nanoparticles offers a promising route toward high-performance electrocatalysis, yet achieving such motifs with clear structure-function correlations remains difficult. Here, iridium (Ir) configurations comprising single atoms (SA), atomic-layer patches (AL), and nanoparticles (NP) were constructed on tricopper phosphide nanowires as a model platform, yielding IrSA/Cu3P, IrAL/Cu3P, and IrNP/Cu3P, respectively. This configuration-defined catalyst series reveals distinct structure-dependent alkaline hydrogen evolution behavior. The atomic-layer iridium patches exhibit a mixed-valence interfacial state and anisotropic lattice distortion, as established by complementary microscopy, spectroscopy, and scattering analyses. Theory further reveals an edge-to-core charge gradient and indicates that this electronically graded interface optimizes Ir 5d states to facilitate water dissociation and balance hydrogen adsorption/desorption. Consequently, the iridium atomic-layer catalyst achieves an overpotential of 27 mV at 10 mA cm-2 and reaches 1 A cm-2 at a cell voltage of 1.68 V in an anion exchange membrane electrolyzer. This work establishes mixed-valence atomic-layer metal patches as a functional platform for interfacial electrocatalysis.
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