Triggering Pt Active Sites in Basal Plane of Van der Waals PtTe 2 Materials by Amorphization Engineering for Hydrogen Evolution.

Exposing active sites and optimizing their bonding strength to reaction intermediates are two essential strategies to significantly improve the catalytic performance of two-dimensional (2D) materials. However, pursuing an efficient way to achieve these goals simultaneously remains a considerable challenge. Here, using 2D PtTe 2 van der Waals material with well-defined crystal structure and atomically thin thickness as a model catalyst, we observe that a moderate calcination strategy can promote the structural transformation of 2D crystal PtTe 2 nanosheets (c-PtTe 2 NSs) into oxygen-doped 2D amorphous PtTe 2 NSs (a-PtTe 2 NSs). The experimental and theoretical investigations cooperatively reveal that oxygen dopants can break the inherent Pt-Te covalent bond in c-PtTe 2 NSs, thereby triggering the reconfiguration of interlayer Pt atoms and exposing them thoroughly. Meanwhile, the structural transformation can effectively tailor the electronic properties (e.g., the density of state near the Fermi level, d-band center, and conductivity) of Pt active sites via the hybridization of Pt 5d orbitals and O 2p orbitals. As a result, a-PtTe 2 NSs with large amounts of exposed Pt active sites and optimized binding strength to hydrogen intermediates exhibit excellent activity and stability in hydrogen evolution reaction. This article is protected by copyright. All rights reserved.