Abstract: The invention relates to the field of mesoporous materials and in particular to mesoporous rare earth oxides and a method of their synthesis.

Abstract: A method of producing nanostructures by supplying particulate solid and gaseous reactants to a reactor, heating the reactor to an elevated temperature and causing relative movement of the solid reactants such as to promote the growth of nanostructures. A high temperature reactor for performing the method includes a reactor chamber having an inlet and an outlet, multiple drums for accommodating solid reactant material, a drive system that causes rotation of the drums and a heating system for heating the chamber. There is also disclosed a method of producing Silicon Nitride nanostructures by supplying solid reactants to a reactor including a carbon source and SiO2, supplying reactant gas to the reactor and maintaining a reactant gas flow rate so as to achieve a desired dwell time and heating the reactor to an elevated temperature.