Hydrothermal preparation of nanotubular particles of a 1:1 nickel phyllosilicate

Hydrothermal treatment of a mixture of nickel chloride, silicic acid and sodium hydroxide at a relatively low temperature, 250 °C and pressure, 10 MPa gave a 1:1 nickel phyllosilicate, [Ni3Si2O5(OH)4] composed exclusively of hollow, open ended, multiwall nanotubular particles, up to 200 nm in length. No other phases, in particular no silicate platelets were seen. Previous reports on the hydrothermal preparation of tubular nickel phyllosilicate emphasized the need for high temperatures and pressures (ca 400 °C and 70 MPa), with lower temperature giving mostly small thin plate-like products. The tubular particles obtained also had larger outer diameters, 25–30 nm, and larger inner hollow cores, about 10 nm in diameter than nickel silicate nanotubes prepared at high temperatures and pressures. The XRD pattern of the product matched that of pecoraite, the nickel analogue of the tubular magnesium silicate mineral chrysotile. N2-sorptometry showed the product was mesoporous with a broad range of pore sizes centred around 170 Å, and a BET surface area of 110 m2/g.