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Reactions of SnBu 3 Cl, TiCl 4 and NH 4 OH in ethanol followed by pyrolysis of the resultant product at 550• C, either in an atmosphere of oxygen or hydrogen, yielding new SnO 2 -TiO 2 based composites. In all, eight products were prepared with weight ratios of Sn-TiO 2 of 0% (1), 5% (2), 15% (3) and 30% (4) in O 2 and 0% (5), 5% (6), 15% (7) and 30% (8) in H 2 . XRD revealed diffraction patterns of TiO 2 (anatase) in the composites, but not those of SnO 2 due to its insufficient crystallinity. Scanning electron microscopy indicated the presence of Sn metal on the surface of composites 6-8. 119 Sn Mössbauer experiments revealed SnO 2 in all samples, and increasing amounts of tin in samples 7 and 8, respectively. The composites were used in experiments of photocatalytic degradation of indigo carmine dye. The catalytic experiments monitored by mass spectrometry and electronic spectroscopy revealed that, in the conditions of the experiments, composite 8 displays the highest activity. In addition, degradation products were characterised using electrospray ionization mass spectrometry (ESI-MS and ESI-MS/MS) data.

Preparation of tin(II ] (4). Phase-pure tin(II) sulfide has been obtained by pyrolysis of these precursors at 350• C in N 2 . Thermogravimetric analysis, X-ray powder diffraction, scanning electron microscopy, X-ray electron probe microanalysis and 119 Sn Mössbauer spectroscopy revealed that the complexes decompose in a single and sharp step (1 and 2), or in pseudo-single stage (3 and 4), to produce SnS. We have also measured the bandgap energies of the residues using electronic spectroscopy in the solid state and the result relates well to that in the literature for SnS, 1.3 eV. A decomposition mechanism was also proposed for each complex based on electrospray ionization tandem mass spectrometric results. The synthetic method used in this work might be useful for the preparation of pure SnS on a large scale.