Coupling Effect of Piezo-Flexocatalytic Hydrogen Evolution with Hybrid 1T- and 2H-Phase Few-Layered MoSe_2 Nanosheets

摘要

Hybrid 1T- and 2H-phase MoSe(2)nanosheets with active reaction sites, which display strong piezoelectric responses and extraordinary flexoelectric potential (flexopotential), are demonstrated. The strain-induced piezoelectric potential (piezopotential) establishes at interfacial areas between 1T and 2H-phase that modulates the local-contact characteristics to enhance charge separation. The piezo- and flexopotential coupling effect is observed not only on edge-site MoSe(2)nanosheets but also on polarized surfaces of the MoSe(2)nanosheets across the top and bottom surfaces, thus establishing an internal electric field to separate electron-hole pairs and proceeding with electrochemical reaction with polar molecules, generating hydrogen gas at approximate to 5000 mu mol g(-1)h(-1). The nanosheets assemble nanoflowers with abundant edge-sites, which serve as cantilever beams for traction force at the free ends of nanosheets. On increasing the bending moment, an extraordinary flexopotential results along thez-axis. The strain gradients induce piezo-flexoelectric coupling effects on numerous edge-site nanosheets, structural boundaries, and the polarized surface along thez-axis, which potentially facilitate a state-of-the-art catalytic hydrogen evolution reaction.