Abstract
Ionic liquids are green solvents that have wide applications in material synthesis, catalysis, and separation. A model switchable ionic liquid (SWIL) consisting of 1,8-diazabicycloundec-7-ene (DBU) and 1-hexanol with carbon dioxide (CO2) as the trigger gas is chosen to synthesize nanocrystalline green rust. Under anoxic conditions, by adding iron (II) acetate (Fe(C2H3O2)2) and methanol to the degassed SWIL, a nanoparticulate green rust with carbonate (nano-GR) is synthesized. More importantly, the molecular structural change of the ionic liquid resulting in green rust crystallines is first characterized using in situ liquid using time-of-flight secondary ion mass spectrometry (ToF-SIMS) coupled with the system for analysis at the liquid vacuum interface (SALVI), a vacuum compatible microfluidic reactor in this work. Dimers and ionic clusters consisting ferric and ferrous ions are identified in liquid ToF-SIMS spectra. Spectral principal component analysis is used to confirm that these ion pairs including dimers and cluster ions are different from nonionic liquids. The results show that liquid ToF-SIMS can be a useful tool to study complex liquids at the molecular level providing insights into predicative synthesis of nanomaterials using environmentally friendly green solvents and giving unique visualization of the evolving material interface due to nucleation.
| Original language | English |
|---|---|
| Article number | 2000452 |
| Journal | Advanced Materials Interfaces |
| Volume | 7 |
| Issue number | 15 |
| DOIs | |
| State | Published - Aug 1 2020 |
Funding
Y.J.S. and Y.F. contributed equally to this work. The authors are grateful for the support from the Pacific Northwest National Laboratory (PNNL) Materials Synthesis and Simulation across Scales Initiative (MS). Part of the research was performed in the W. R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by OBER and located at PNNL, via the general user proposals 49694 and 50569. PNNL is operated by Battelle for the DOE under Contract DE‐AC05‐76RL01830. Y.J.S. was grateful for the support from China Scholarship Council (CSC) and the PNNL Alternative Sponsored Fellowship (ASF). 3 Y.J.S. and Y.F. contributed equally to this work. The authors are grateful for the support from the Pacific Northwest National Laboratory (PNNL) Materials Synthesis and Simulation across Scales Initiative (MS3). Part of the research was performed in the W. R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by OBER and located at PNNL, via the general user proposals 49694 and 50569. PNNL is operated by Battelle for the DOE under Contract DE-AC05-76RL01830. Y.J.S. was grateful for the support from China Scholarship Council (CSC) and the PNNL Alternative Sponsored Fellowship (ASF).
Keywords
- green rust
- in situ liquid ToF-SIMS
- SALVI
- structural evolution
- switchable ionic liquids