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RESEARCH PRODUCT

2.8NiO–H1.8Ni0.6(OH)MoO4—Novel nanocomposite material for the reactive adsorption of sulfur-containing molecules at moderate temperature

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Abstract It has been found that a poorly crystalline green precipitate that forms in boiling ammonia solution of Ni(NO 3 ) 2 and (NH 4 ) 6 Mo 7 O 24 yields on annealing a Ni-rich material (Ni/Mo = 3.4) containing slit shaped mesopores and exhibiting the BET surface area of 230 m 2 /g. Characterization of the material by TGA, XRD, TEM, SEM, and EXAFS allowed to determine that it is a nanocomposite consisting of Ni–Mo (hydro)oxide layers H 1.8 Ni 0.6 (OH)MoO 4 which are pillared by NiO nanoparticles ( D  = 3 nm). The structure of the layers appears to be similar to that found in the previously described crystalline molybdate (NH 4 )HNi 2 (OH) 2 (MoO 4 ) 2 prepared in the similar conditions. The obtained nanocomposite 2.8NiO–H 1.8 Ni 0.6 (OH)MoO 4 can be completely reduced in H 2 flow at 300 °C yielding unsupported Ni 3.4 Mo bimetallic nanoparticles ( D  = 3.6 nm) which are stable towards sintering. The material shows remarkable activity in a moderate temperature reactive adsorption of thiophene: at 300 °C the rate of its sulfidation in the presence of thiophene is an order of magnitude higher than that of conventional Ni/ZnO sorbent. Such increase of activity is attributed to formation (after partial sulfidation) of the mixed Ni–Mo–S phase, which is known to be highly active in catalytic hydrodesulfurization of sulfur-containing molecules. Also, due to its open structure the nanocomposite reacts rapidly and completely with H 2 S even at 200 °C, while only the surface sulfidation is observed for ZnO nanoparticles under the same conditions.