Electrocatalytic Hydrogen Evolution Reaction on Edges of a Few Layer Molybdenum Disulfide Nanodots

TL;DR

This paper reports the synthesis of molybdenum disulfide nanodots with enhanced electrocatalytic activity for hydrogen evolution, demonstrating their potential as efficient, durable catalysts for clean energy applications.

Contribution

First demonstration of MoS2 nanodots synthesized via ionic liquid exfoliation with improved HER catalytic performance.

Findings

Nanodots have a thickness of up to 7 layers and lateral size below 20 nm.

Achieved a Tafel slope of 61 mV/dec and onset potential of -0.09 V vs RHE.

Nanodots show good durability in acidic electrolyte.

Abstract

The design and development of inexpensive highly efficient electrocatalysts for hydrogen production, underpins several emerging clean-energy technologies. In this work, for the first time, molybdenum disulfide (MoS2) nanodots have been synthesized by ionic liquid assisted grinding exfoliation of bulk platelets and isolated by sequential centrifugation. The nanodots have a thickness of up to 7 layers (4 nm) and an average lateral size smaller than 20 nm. Detailed structural characterization established that the nanodots retained the crystalline quality and low oxidation states of the bulk material. The small lateral size and reduced number of layers provided these nanodots with an easier path for the electron transport and plentiful active sites for the catalysis of hydrogen evolution reaction (HER) in acidic electrolyte. The MoS2 nanodots exhibited good durability and a Tafel slope of 61 mVdec-1 with an estimated onset potential of -0.09 V vs RHE, which are considered among the best values achieved for 2H phase. It is envisaged that this work may provide a simplistic route to synthesize a wide range of 2D layered nanodots that have applications in water splitting and other energy related technologies. KEYWORDS: MoS2 nanosheets, hydrogen evolution reaction, electrocatalysis, edges, nanodots, ionic liquid exfoliation, water splitting