CRYSTAL-STRUCTURE OF A POROUS ZIRCONIUM PHOSPHATE PHOSPHONATE COMPOUND AND PHOTOCATALYTIC HYDROGEN-PRODUCTION FROM RELATED MATERIALS/

The preparation, structure, and catalytic properties of porous zirconi um phosphate/phosphonate compounds are discussed. The crystal structur e for the Zr-2(PO4)(O3PCH2CH2(viologen)CH2CH2PO3)X(3) . 3H(2)O, X = ha lide, is presented. The structure was determined ab initio from X-ray powder diffraction data and refined by Rietveld methods. The compound crystallizes with the symmetry of space group P2/c with a = 13.589(2) Angstrom, b = 8.8351(9) Angstrom, c = 9.229(1) Angstrom, and beta = 10 0.79 degrees. The structure consists of inorganic lamellae bridged by phosphono-ethyl-viologen groups. Large pores are formed in this materi al, which contain one halide ion and three water molecules per formula unit. The free halide ions in these materials are readily exchanged f or PtCl(4)(2-)ions. The Pt salt was reduced to give fine metal particl es inside the porous solid. These materials produce hydrogen photochem ically from water using ultraviolet light. The average rate of H-2 pro duction is 0.15 mL/h with a lower limit quantum yield of 4% based only on the ultraviolet portion of the spectrum in the presence of a sacri ficial reductant (EDTA).