Monodisperse mesoporous anatase titania beads with high surface areas and tunable pore size and grain diameter have been prepared through a combined sol-gel and solvothermal process in the presence of hexadecylamine (HDA) as a structure-directing agent. The monodispersity of the resultant titania beads, along with the spherical shape, can be controlled by varying the amount of structure-directing agent involved in the sol-gel process. The diameter of the titania beads is tunable from approximately 320 to 1150 nm by altering the hydrolysis and condensation rates of the titanium alkoxide. The crystallite size, specific surface area (from 89 to 120 m(2)/g), and pore size distribution (from 14 to 23 nm) of the resultant materials can be varied through a mild solvothermal treatment in the presence of varied amounts of ammonia. On the basis of the results of small-angle XRD, high-resolution SEM/TEM, and gas sorption characterization, a mechanism for the formation of the monodisperse precursor beads has been proposed to illustrate the role of HDA in determining the morphology and monodispersity during the sol-gel synthesis. The approach presented in this study demonstrates that simultaneous control of the physical properties, including specific surface area, mesoporosity, crystallinity, morphology, and monodispersity, of the titania materials can be achieved by a facile sol-gel synthesis and solvothermal process.

1 This article will form part of a virtual special issue on advanced neutron scattering instrumentation, marking the 50th anniversary of the journal.QUOKKA is a 40 m pinhole small-angle neutron scattering instrument in routine user operation at the OPAL research reactor at the Australian Nuclear Science and Technology Organisation. Operating with a neutron velocity selector enabling variable wavelength, QUOKKA has an adjustable collimation system providing source-sample distances of up to 20 m. Following the largearea sample position, a two-dimensional 1 m 2 position-sensitive detector measures neutrons scattered from the sample over a secondary flight path of up to 20 m. Also offering incident beam polarization and analysis capability as well as lens focusing optics, QUOKKA has been designed as a general purpose SANS instrument to conduct research across a broad range of scientific disciplines, from structural biology to magnetism. As it has recently generated its first 100 publications through serving the needs of the domestic and international user communities, it is timely to detail a description of its asbuilt design, performance and operation as well as its scientific highlights. Scientific examples presented here reflect the Australian context, as do the industrial applications, many combined with innovative and unique sample environments. research papers J. Appl. Cryst. (2018). 51, 294-314 Kathleen Wood et al. QUOKKA 295 Figure 1 QUOKKA instrument layout. research papers J. Appl. Cryst. (2018). 51, 294-314 Kathleen Wood et al. QUOKKA 297 Figure 3(a) Attenuator wheel. (b) Automatic aperture changer. (c) Sample environment area, showing the extendable bellows on the left and the 20position sample changer on the right. Downstream of the sample changer, the entrance to the detector tank is visible. (d) Beamstop mechanism, with the six beamstops all in the 'in beam' position.research papers J. Appl. Cryst. (2018). 51, 294-314 Kathleen Wood et al. QUOKKA 299 research papers J. Appl. Cryst. (2018). 51, 294-314 Kathleen Wood et al. QUOKKA 301 research papers J. Appl. Cryst. (2018). 51, 294-314 Kathleen Wood et al. QUOKKA 313