1t'-mote2-based on-chip electrocatalytic microdevice: A platform to unravel oxidation- dependent electrocatalysis

Abstract

Ultrathin transition metal dichalcogenides (TMDs) are of particular interest as low-cost alternatives to highly active electrocatalysts because of their high surface activation energy. However, their striking structural characteristics cause chemical instability and undergo oxidation easily. Establishing a transparent material model for unraveling oxidation-dependent electrocatalysis is of great importance for designing more efficient electrocatalysts. Herein, we fabricated an on-chip microcell that uses an individual nanosheet as the working electrode to evaluate the contribution of a single oxidation factor to hydrogen evolution reaction (HER) performance in the generation of oxidative molybdenum ditelluride (MoTe2) for the fabrication of the on-chip electrocatalytic device. Moreover, O2 plasma technology was utilized to control the degree of oxidation accurately by the processing time. Using oxidized MoTe2 as a prototype demonstrated lower onset overpotential and activation energy of HER performance, which was optimized to some degree by oxidation. The incorporated oxygen during the oxidation process as an electron density modulator could manipulate the electron densities and contribute to the enriched surface charge and lower Gibbs reaction energy. Our present work provides atomic-level insights into the role of surface oxide in ultrathin TMDs HER catalysis by an on-chip electrocatalytic microdevice and the semiquantification of the model-structure- performance relationship, thus, opening the door for designing catalytic centers.