Controllable growth of two dimensional stereoscopic PtTe2 nanosheets for efficient electrocatalytic hydrogen evolution

Abstract

Among the transition metal dichalcogenide family, two-dimensional (2D) PtTe₂ has emerged as a promising electrocatalyst for the hydrogen evolution reaction (HER), due to its high edge catalytic activity, excellent conductivity and chemical stability, etc. However, the active sites of 2D PtTe₂ synthesized on conventional planar insulating substrates are limited to the edges, and the traditional synthetic method is not compatible with low-cost batch production. Herein, we report the large-area uniform growth of stereoscopic PtTe₂ nanosheets on highly conductive, carbon cloth substrates featuring abundant active sites and tunable thicknesses (from ∼3.0 nm to bulk state), via a facile chemical vapor deposition route. We find that the stereoscopic structure of PtTe₂ on the carbon fiber surface can facilitate efficient electron transport from the conductive carbon cloth to the active edge sites of the PtTe₂ nanosheets along the in-plane direction. And the catalytic activity can be significantly improved by increasing the average nanosheet thickness from ∼3.0 to 7.5 nm, leading to an ultra-low overpotential of ∼38.8 mV at the current density of 10 mA cm⁻² and a rather low Tafel slope of ∼59.2 mV dec⁻¹. Hereby, this work is expected to deepen our understanding of the thickness-dependent catalytic activity of 2D layered materials, and stimulate further structure design and synthesis explorations of 2D catalysts on 3D templates for highly efficient water splitting related applications.