How to deposit a thin layer of lanthanum metal inside the porous structure of a gel? The gel itself is not going to react with $\ce{La}$ but how to make sure that the byproducts are removable by solvent exchange after the deposition process? Alternatively, if the precursors are necessarily vapors, aerogel must be used as a template.
Which approach to try:
- Make the gel electrically conductive (by adding carbon to it), use a nonmetallic solvent, and deposit $\ce{La}$ electrolytically from a solution.
- Find a thermally activated set of precursors (I don't know any), heat until decomposition yields $\ce{La}$ without any unwanted solid products.
Without other reactants, some of the most volatile $\ce{La}$ compounds apparently always yield solid compounds on pyrolysis, along with hydrogen-rich gas. For example:
pyrolysis of rare earth Cp compounds at temperatures > 500 °C is known to yield primarily H2 as the gas-phase product.
