NOVELTY - Producing two-dimensional nanomaterials, comprises: (a) providing (a1) a mixture comprising graphene oxide particles, water and at least one cationic surfactant and/or non-ionic surfactant; (b) adding at least one sol precursor compound to the mixture; (c) reacting the mixture in a sol/gel process to form gel from the sol precursor compound on the graphene oxide particles or, respectively, the graphene particles; (d) removing the surfactant; and (e) optionally heating the gel-coated graphene oxide particles to reduce the graphene oxide to graphene.    USE - The two-dimensional sandwich nanomaterial is useful: as template for producing further nanolayer materials; manufacturing catalysts, sensors, capacitors, primary and secondary electrochemical cells and fuel cells; and producing graphene particles (all claimed).    ADVANTAGE - The two-dimensional sandwich nanomaterial produces graphene particles with high yield and high purity in a less time-consuming manner. The graphene particles exhibit high mechanical strength and high electrical conductivity.    DETAILED DESCRIPTION - Producing two-dimensional nanomaterials, comprises: (a) providing (a1) a mixture comprising graphene oxide particles, water and at least one cationic surfactant and/or non-ionic surfactant or (a2) a mixture comprising graphene particles, at least one solvent useful for solution exfoliation of graphite and at least one cationic surfactant and/or non-ionic surfactant; (b) adding at least one sol precursor compound to the mixture; (c) reacting the mixture in a sol/gel process to form gel from the sol precursor compound on the graphene oxide particles or, respectively, the graphene particles; (d) removing the surfactant; and (e) optionally heating the gel-coated graphene oxide particles for at least 1 minute to at least 500 degrees C under inert gas atmosphere to reduce the graphene oxide to graphene. INDEPENDENT CLAIMS are included for:    (1) a two-dimensional sandwich nanomaterial obtained by the process; and    (2) producing graphene particles comprising the steps (a)-(e) as above per se and (h) removing the silicon dioxide from the graphene oxide particles or, respectively, the graphene particles, where the step (e) is carried out when the step (a) provides the mixture containing (a1).