Christopher Breshike I think that the phase diagrams for Ti and oxygen plus the Pourbaix diagram for TiO2 and water mean that a low temperature sol-gel process for Ti2O3 is thermodynamically unfeasible. The usual route to Ti2O3 is high temperature synthesis fusing Ti with TiO2 at 16660 C or so. Correct me if I'm wrong - I learn more that way. See, for example the attached.

Christopher Breshike From:

Article Transition of Self-Passivation and Semiconductor Property of...

This is very helpful and explains why I can only find ball milling routes to make nanoparticles of ti2o3. Thanks very much

Christopher Breshike Even ball milling to get < 100nm is problematic as powders contain no discrete, independent, separate particles < 100 nm, but rather a mass of sub-micron fused aggregates and looser agglomerates. You'll need a huge amount of energy in a colloid mill to get even close and contamination is the biggest issue. There's a 'comminution limit' (a good term for you to Google!). More of the physics and physical chemistry in this webinar (free registration required):

Dispersion and nanotechnology

https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W190528DispNanoMat