Hydrothermal Synthesis of Hydrosilicate Nanoscrolls (Mg 1 – x Co x ) 3 Si 2 O 5 (OH) 4 in a Na 2 SO 3 Solution

Single-phase nanotubular hydrosilicates (Mg 1 – x Co x ) 3 Si 2 O 5 (OH) 4 ( x = 0.2, 0.4, …, 1) with a chrysotile structure were obtained by hydrothermal treatment at 200°C. Materials based on cobalt-containing hydrosilicates can be used as catalysts, sorbents, and sensors and in energy storage and accumulation devices. Nanotubular cobalt-containing hydrosilicates are difficult to produce because of the presence of oxygen in the system and, as a consequence, the oxidation of cobalt to Co 3+ . To stabilize Co 2+ , at the stage of hydrothermal treatment, a sodium sulfite solution was used to chemically remove oxygen from the system. The samples obtained were nanoscrolls of various morphologies. An increase in the cobalt content in the system led to the formation of multi-walled and double-walled cylinders, cones, tube-in-tube nanoscrolls, and also nanoscrolls with fully or partially closed ends, curved nanoscrolls, and spheroidal particles.