In-plane strain engineering in ultrathin noble metal nanosheets boosts the intrinsic electrocatalytic hydrogen evolution activity

While inducing strain to noble metal nanomaterials can modulate catalytic activities, the strain is often spatially dependent. Here, authors manipulate the planar strain in noble metal nanosheets for hydrogen evolution electrocatalysis by constructing amorphous-crystalline phase boundaries. Strain has been shown to modulate the electronic structure of noble metal nanomaterials and alter their catalytic performances. Since strain is spatially dependent, it is challenging to expose the active strained interfaces by structural engineering with atomic precision. Herein, we report a facile method to manipulate the planar strain in ultrathin noble metal nanosheets by constructing amorphous-crystalline phase boundaries that can expose the active strained interfaces. Geometric-phase analysis and electron diffraction profile demonstrate the in-plane amorphous-crystalline boundaries can induce about 4% surface tensile strain in the nanosheets. The strained Ir nanosheets display substantially enhanced intrinsic activity toward the hydrogen evolution reaction electrocatalysis with a turnover frequency value 4.5-fold higher than the benchmark Pt/C catalyst. Density functional theory calculations verify that the tensile strain optimizes the d-band states and hydrogen adsorption properties of the strained Ir nanosheets to improve catalysis. Furthermore, the in-plane strain engineering method is demonstrated to be a general approach to boost the hydrogen evolution performance of Ru and Rh nanosheets.

Automated summary

Strain modulation of noble metal nanosheets through constructing amorphous-crystalline phase boundaries enhances their catalytic activities, particularly towards the hydrogen evolution reaction. By inducing surface tensile strain through in-plane amorphous-crystalline boundaries, the strained nanosheets display substantially improved intrinsic activity, demonstrating a general approach to boost hydrogen evolution performance of various noble metal nanosheets like Ir, Ru, and Rh.