Synthesis and characterisation of MCM-41 supported nickel oxide catalysts

Nickel ions were deposited onto hydrothermally synthesised all-silica MCM-41 by means of incipient wetness impregnation with different nickel precursor solutions, viz, nickel nitrate and nickel citrate. The calcined nickel catalysts (10 wt.% Ni) were characterised using nitrogen physisorption, temperature programmed reduction, transmission electron microscopy. X-ray diffraction and X-ray photo-electron spectroscopy. With nickel citrate the highest nickel oxide dispersion was obtained. The nickel oxide particle size was inferred to be very small with this precursor, allowing the particles to be located mainly inside the mesopores of MCM-41. With nickel nitrate a bimodal particle size distribution was obtained and next to small nickel oxide particles inside the mesopores relatively large particles (i.e. > 10 nm) were present on the external surface of the support, thus lowering the dispersion of this catalyst. Textural analysis showed that with both preparation methods neither pore-blocking nor structural collapse of the support occurred. From these results it is concluded that incipient wetness impregnation with a nickel citrate precursor solution is an excellent method to prepare MCM-41 supported nickel catalysts combining both a high metal loading and a high dispersion of the active phase. (C) 2001 Elsevier Science B.V. All rights reserved.