Enhancing Photoelectrocatalysis with Activated MoS2 Grain Boundaries

Radha Raman^1,2,3,4,5*, Ya-Ping Hsieh², Mario Hofmann⁵

¹Physics, National Central University, Taoyuan City, Taiwan
²Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
³Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
⁴Molecular Science and Technology Program, Academia Sinica, Taipei, Taiwan
⁵Physics, National Taiwan University, Taipei, Taiwan

* Presenter:Radha Raman, email:radharaman696@gmail.com

MoS2 has gained prominence in catalysis and sustainable energy conversion, yet its basal plane's electrochemical inertness hinders large-scale electrocatalysis. To address this challenge, we introduce a novel technique that selectively activates the buried grain boundaries (GBs) in continuous MoS2. Mild UV irradiation significantly enhances the reactivity of MoS2 GBs, approaching levels observed at the edges. This transformation is validated using site-selective photo-deposition and micro-electrochemical hydrogen evolution reaction (HER) measurements.
Our comprehensive analysis, including spectroscopy and ab-initio simulations, attributes this catalytic enhancement to substitutional oxygen functionalization at the grain boundaries. This development not only boosts active site density in MoS2 catalysis but also introduces a novel approach to photocatalytic conversion.
By exploiting electronic structure differences between activated GBs and the basal plane, we engineer homo-compositional junctions that improve photocatalytic hydrogen synthesis by 47%, surpassing other catalytic sites. Our findings represent a significant advancement in MoS2's application for advanced electrochemical and photocatalytic processes.

Keywords: Molybdenum disulfide, Grain boundaries, Photodeposition , Photocatalysis, Hydrogen Evolution Reaction