Particle stabilized emulsions are nothing surprising. And once you say nanoparticle stabilized emulsion, there's a plethora of everyday examples of air-water emulsions: shaving foam, whipped egg whites, aquafaba etc. Main difference here is that unlike e.g. proteins from egg white, the nano-silica particles do not stick to each other.

The article does have some good sources. So I think it is legitimate.

Why wouldn't it be? The mechanism to create it sounds very plausible.