Boosting Water Dissociation Kinetics on Pt-Ni Nanowires by N-Induced Orbital Tuning.
basic_science · Level V
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- Record sourced from PubMed, PMID 30811711.
- Also identified by DOI 10.1002/adma.201807780.
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Abstract
Although it is commonly believed that the water-dissociation-related Volmer process is the rate-limiting step for alkaline hydrogen evolution reaction (HER) on Pt-based catalysts, the underlying essence, particularly on the atomic scale, still remains unclear. Herein, it is revealed that the sluggish water-dissociation behavior probably stems from unfavorable orbital orientation and the kinetic issue is successfully resolved via N-induced orbital tuning. Impressively, N modified Pt-Ni nanowires deliver an ultralow overpotential of 13 mV at 10 mA cm<sup>-2</sup> , which represents a new benchmark for alkaline HER catalysis. Fine-structural characterization and density functional theory analysis illustrate that the introduced nitrogen can uniquely modulate the electron densities around the Ni sites, and further create empty d<sub>z</sub> <sup>2</sup> orbitals with superior orientation for water adsorption and activation. More importantly, it is demonstrated that N-induced orbital modulation can generally boost the alkaline HER activities of Pt-Co, Pt-Ni, and Pt-Cu, offering a new perspective for the design of HER catalysts and beyond.