(Invited) Enhanced Catalysis of Surface-Activated Metallic WSe2 Nanosheets By Single-Atom Pt for High-Performance Li-O2 Battery

Abstract

Layered materials, such as TMDCs, exhibit various electronic structures attributed to their polymorphism and can be further modificated at the atomic level through chemical treatments. TMDCs in the metallic phase (1T or 1T’ phase) have gained attention as efficient electrocatalystic materials, due to their exceptional transport properties compared to TMDCs in the semiconducting phase (2H phase). TMDCs with the metallic phase have been prepared by atomic-scale post-treatments, such as an intercalation and single-atom doping. However, the precise role of these post-treatments in the catalytic performance of TMDCs is still ambiguous, as it is uncertain whether the enhanced properties arise from charge transfer kinetics in metallic phase or electrochemical properties induced by the post-treatment.Herein, we present a straightforward approach fabrication for fabricating metallic WSe2 nanosheets, which serve as an excellent support for single-atom Pt doping. The incorporation of single-atom Pt into WSe2 nanosheets was achieved using a simple solution method at room temperature. Extensive measurements were conducted, including XAS, XPS, and XPDF to investigate the local coordination structure of Pt-WSe2. These measurements confirmed the presentce of single-atom Pt doping within WSe2 layers. The introduction of single-atom Pt significantly enhanced the kinetics of the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), leading to improved performance of Li-O2 batteries. Experimental measurements and DFT calculations provided evidence that the enhanced catalytic abilities of Pt-WSe2 originated from the improved interaction between oxygen and the Se vacancy on basal planes of WSe2. Consequently, the Li-O2 battery incorporating the Pt-WSe2 catalyst exhibited a stable discharge and charge cycle for up to 350 cycles, demonstrating its superior durability.