Engineering grain boundaries at the 2D limit for the hydrogen evolution reaction.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31896753.
- Also identified by DOI 10.1038/s41467-019-13631-2 and PMC identifier 6940382.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Atom-thin transition metal dichalcogenides (TMDs) have emerged as fascinating materials and key structures for electrocatalysis. So far, their edges, dopant heteroatoms and defects have been intensively explored as active sites for the hydrogen evolution reaction (HER) to split water. However, grain boundaries (GBs), a key type of defects in TMDs, have been overlooked due to their low density and large structural variations. Here, we demonstrate the synthesis of wafer-size atom-thin TMD films with an ultra-high-density of GBs, up to ~1012 cm-2. We propose a climb and drive 0D/2D interaction to explain the underlying growth mechanism. The electrocatalytic activity of the nanograin film is comprehensively examined by micro-electrochemical measurements, showing an excellent hydrogen-evolution performance (onset potential: -25 mV and Tafel slope: 54 mV dec-1), thus indicating an intrinsically high activation of the TMD GBs.