Porous organic-inorganic hybrid nickel phosphonate: Adsorption and catalytic applications

A new crystalline porous organic-inorganic hybrid nickel phosphonate material HPNP-1 has been synthesized hydrothermally in the absence of any template or structure-directing agent (SDA) using an organophosphorus precursor hexamethylenediamine-N, N, N', N'-tetrakis-(methylphosphonic acid) (HDTMP). Powder XRD results suggested the formation of a new tetragonal phase (a = 14.169 angstrom; c = 16.202 angstrom and unit cell volume 3252.8 angstrom(3)) and N-2 sorption analyses revealed the existence of supermicroporous along with inter particle mesoporosity in this material. FT IR and UV-vis spectroscopic results suggested that the organic moiety of the organophosphorus precursor molecule has been preserved in this hybrid framework. Due to the presence of surface phosphonate groups this organic-inorganic hybrid material shows very high affinity for the adsorption of metal cations like Cr3+, Pb2+, Hg2+ and Cd2+, and thus can be very efficiently utilized in the adsorption of these heavy metal ions from polluted water. Further, the material showed excellent catalytic activity and selectivity in the reduction of nitrobenzenes to the respective anilines in the presence of NaBH4 as the reducing agent. (C) 2012 Elsevier Inc. All rights reserved.