Ultrasmall and phase-pure W<sub>2</sub>C nanoparticles for efficient electrocatalytic and photoelectrochemical hydrogen evolution.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27752046.
- Also identified by DOI 10.1038/ncomms13216 and PMC identifier 5071847.
- 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
Earlier research has been primarily focused on WC as one of the most promising earth-abundant electrocatalysts for hydrogen evolution reaction (HER), whereas the other compound in this carbide family-W<sub>2</sub>C-has received far less attention. Our theoretical calculations suggest that such a focus is misplaced and W<sub>2</sub>C is potentially more HER-active than WC. Nevertheless, the preparation of phase pure and sintering-free W<sub>2</sub>C nanostructures represents a formidable challenge. Here we develop an improved carburization method and successfully prepare ultrasmall and phase-pure W<sub>2</sub>C nanoparticles. When evaluated for HER electrocatalysis, W<sub>2</sub>C nanoparticles exhibit a small onset overpotential of 50 mV, a Tafel slope of 45 mV dec<sup>-1</sup> and outstanding long-term cycling stability, which are dramatically improved over all existing WC-based materials. In addition, the integration of W<sub>2</sub>C nanoparticles with p-type Si nanowires enables highly active and sustainable solar-driven hydrogen production. Our results highlight the great potential of this traditionally non-popular material in HER electrocatalysis.