Xenon adsorption has been studied in different ion-exchanged forms of synthetic chabazite zeolites, K–, Ca–, Li–, Rb– and Cs–CHA, at low pressures and variable temperature. The xenon adsorption capacities vary with the nature of the exchanged cation in a way that is consistent with the known cation locations in the zeolite. Highest uptake was found for Ca–CHA, and lowest for Cs–CHA. The xenon uptakes at room temperature were also consistent with differences in the nitrogen adsorption capacities at 77 K. Enthalpies of adsorption were estimated from the temperature dependence of the adsorption isotherms in Ca–CHA and K–CHA, and found to be very similar. The xenon adsorption was also compared with that of an aluminophosphate (ALPO-CHA) as well as a silicoaluminophosphate (SAPO-34), both having the chabazite-type structure. The high affinity of CHA for xenon is attributed in part to a close match between the size of the xenon atom and the pore dimensions of the CHA structure, the so-called confinement effect.

This paper describes an in situ EPR study of electron trapping in a nanocrystalline rutile material. Irradiation at 4 K with broad-band UV–Vis light gives weak signals of trapped electrons. When irradiation is stopped, intense Ti3+ EPR signals appear, which can be removed again by resuming the irradiation. It is proposed that under irradiation there is a dynamic equilibrium established between creation of conduction band electrons, trapping of electrons, and excitation from trap sites back into the conduction band. When irradiation is stopped, conduction band electrons are trapped and remain so in the dark. Some initial results on the temperature and wavelength dependence of these processes are presented.

The vanadosilicate zeolite AM-6 is shown by a combination of spectroscopic techniques (UV-vis, Raman, XPS, XAS and EPR) to contain linear chains of alternating VO and V–O bonds. The V(IV) ions in these chains are ferromagnetically coupled, and an excellent fit a to the susceptibility data with a one-dimensional Heisenberg model is obtained with J = 0.66(1) cm−1. AM-6 is thus the first reported example of a microporous material incorporating one-dimensional ferromagnetic chains.

EPR spectroscopy has been used to investigate spontaneous and/or photo-induced electron transfer between adsorbed organic molecules and the mesoporous aluminosilicate MCM-41 host. Spontaneous electron transfer occurs from the host to electron acceptor molecules with sufficiently favourable reduction potentials (TCNE, TCNQ, 1,4-benzoquinone, 1,4-naphthaquinone and 1,4-anthraquinone), provided the MCM-41 contains aluminium and the radical anion yield correlates with the aluminium content of the host. The semiquinone radical anions are interacting strongly with exposed Al3+ sites, whereas the TCNE and TCNQ radical anions are loosely bound and can be washed from the host. Radical cation formation is observed when electron donor molecules with favourable oxidation potentials are adsorbed in MCM-41 containing aluminium, and the radical cations formed interact with exposed Al3+ sites. This work shows that aluminium-containing MCM-41 contains both electron donating and electron accepting sites which may intervene in intra-molecular charge separation processes in adsorbed organic molecules.

Al and Ni K-edge XANES and EXAFS experiments have been undertaken to characterise the chemical states of aluminium and nickel in NiZSM-5 catalysts used for the pyrolysis and hydrodehalogenation with methane of Halon 1301 (CF3Br). It is shown that pyrolysis of Halon 1301 over NiZSM-5 involves both extra-framework aluminium fluoride or hydroxyfluoride species and aggregated nickel species, probably fluorided. Reaction products are CF4 and C2F6. The reaction between Halon 1301 and methane over NiZSM-5 produces CHF3 and CH3Br as major, but not exclusive products. In the presence of CH4 framework dealumination and aggregation of nickel is inhibited. Future prospects for utilising these and similar catalysts in reactions of other Halons and CFCs to produce useful fluorocarbon products as an alternative to destruction are briefly discussed.

Irradiation of H-ETS-10 in the presence of adsorbed methanol or ethene causes photoreduction of Ti(IV) to Ti(III); photoreduction does not occur for Na, K-ETS-10, but a photoinduced polymerization of ethene is observed.

The preparation and characterization of a cobalt substituted ETS-10 titanosilicate are described. X-ray diffraction shows that cobalt incorporation causes an increase in unit cell dimensions. UV–VIS, EPR, Raman and Co K-edge XANES spectra all show that Co2+ occupies tetrahedral sites, substituting for silicon. The 29Si NMR spectra do not permit identification of which silicon sites in ETS-10 are substituted, but the Co K-edge EXAFS shows clearly that Co2+ substitutes at Si(3Si,1Ti) sites.

The vanadosilicate zeolite AM-6 is shown by a combination of spectroscopic techniques (UV-vis, Raman, XPS, XAS and EPR) to contain linear chains of alternating VO and V–O bonds. The V(IV) ions in these chains are ferromagnetically coupled, and an excellent fit a to the susceptibility data with a one-dimensional Heisenberg model is obtained with J = 0.66(1) cm−1. AM-6 is thus the first reported example of a microporous material incorporating one-dimensional ferromagnetic chains.