Structure and electrochromism of two-dimensional octahedral molecular sieve h'-WO<sub>3</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30659185.
- Also identified by DOI 10.1038/s41467-018-07774-x and PMC identifier 6338762.
- 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
Octahedral molecular sieves (OMS) are built of transition metal-oxygen octahedra that delimit sub-nanoscale cavities. Compared to other microporous solids, OMS exhibit larger versatility in properties, provided by various redox states and magnetic behaviors of transition metals. Hence, OMS offer opportunities in electrochemical energy harnessing devices, including batteries, electrochemical capacitors and electrochromic systems, provided two conditions are met: fast exchange of ions in the micropores and stability upon exchange. Here we unveil a novel OMS hexagonal polymorph of tungsten oxide called h'-WO<sub>3</sub>, built of (WO<sub>6</sub>)<sub>6</sub> tunnel cavities. h'-WO<sub>3</sub> is prepared by a one-step soft chemistry aqueous route leading to the hydrogen bronze h'-H<sub>0.07</sub>WO<sub>3</sub>. Gentle heating results in h'-WO<sub>3</sub> with framework retention. The material exhibits an unusual combination of 1-dimensional crystal structure and 2-dimensional nanostructure that enhances and fastens proton (de)insertion for stable electrochromic devices. This discovery paves the way to a new family of mixed valence functional materials with tunable behaviors.