Alan Bond tells Journal of Materials Chemistry about his hot paper.

1. Can you briefly describe what you achieved in this article?
In this article we report on the in situ, room temperature spontaneous reduction of Ag⁺ and Au³⁺ in a distillable ionic liquid, DIMCARB, to produce metallic nanostructures with well-defined morphologies. The reduction process leads to spherical nanoparticles, clusters composed of nanoparticles and nanowires of variable length. The use of the ionic liquid bypasses the use of high temperatures and large quantities of toxic and volatile organic solvents and hence offers an alternative route to nanostructure formation. Additionally the distillable nature of the solvent allows facile removal of solvent at relatively low temperatures. The differing morphologies of metallic nanostructures obtained are rationalised in terms of a mechanism involving either kinetic, thermodynamic or surface confined growth mechanisms.

2. Could you explain the significance of your article to the non-specialist? 
This research demonstrates the availablity of a facile route for metallic nanostructure growth with well defined morphologies (including wires and spheres in the nanometre size scale) under conditions that are relatively benign compared to conventional methods. The ionic liquid used allows the in situ reduction and stabilisation of the nanostructures to be accomplished thus reducing the amount of chemicals needed. Additionally, the distillable nature of the ionic liquid allows for straightforward removal of the solvent. Overall this work offers new avenues for nanostructure production whilst emphasising eventual environmentally benign industrial synthetic strategies.

3. What has motivated you to conduct this work? 
Ionic liquids are becoming an important research area in chemistry as possible replacements for conventional solvents, mainly due to their green properties. Our work has focussed on the understanding of fundamental properties of these liquids. In doing so we have found that for some applications, the low vapour pressure of conventional ionic liquids is in fact detrimental to their use. Consequently we have been investigating use of 'distillable ionic liquids' that have some of the advantageous properties of ionic liquids but also have vapour pressures. During the course of our research we observed the spontaneous reduction of Ag⁺ ions in the ionic liquid. Consequently we explored this reaction and investigated the reaction mechanism, and extended this to Au³⁺ reduction.

4. Where do you see this work developing in the future? 
A number of areas within this work still need to be researched with an eventual aim to find optimal conditions for both nanoparticle and/or nanowire synthesis. Once the relevant factors are fully understood, this production method needs to be expanded to encompass other metals of interest not only to academia but also industry. DIMCARB is the simplest of a series of distillable ionic liquids, dialcarbs,  that can be formed. Thus the possibility exist to explore use of other solvents with 'tuneable' solvent properties that can also be investigated for nanostructure production. Additionally routes into templating of the resultant nanostructures need to be investigated, which would then allow a route into nanocircuitry printing.

5. Are there any particular challenges facing future research in this area? 
One major challenge for future research is in synthesis new 'distillable ionic liquids' in highly pure form. Additionally, instead of having adventitious water present (which is required for the reduction process) it would be preferable to develop a synthetic route where the quantity of water present is small and known and hence controlled, thus allowing a control of the reduction rate which will influence the morphologies of the particles formed. Another major challenge is to establish full details of the reduction reaction, thereby allowing selective and sized controlled nanostructure formation.

Alan Bond

Alan M. Bond is the R. L. Martin Distinguished Professor of Chemistry & Federation Fellow at Monash University, Melbourne, Australia. He is the author or co-author of over 600 papers and patents and 2 books and recipient of more than 20 distinguished awards which include the senior prizes of the Royal Australian Chemical Institute in Inorganic Chemistry (Burrows Medal), Analytical Chemistry and Electrochemistry (Stokes Medal), as well as the most prestigious H.G. Smith Medal offered by that institute. The award of the year 2000 UK Royal Society of Chemistry Faraday Medal, the Robert Boyle 150th Anniversary Fellowship, the Oxford University Hinshelwood Lectureship, the 2005 Reilley Medal and an Australian Research Council Federation Fellowship, are other examples of recognition. Professor Bond has also been elected to the Australian Academy of Science and its Council. Professor Bond is or has been a member of international editorial boards encompassing disciplines such as surface science, computing, analytical chemistry, inorganic chemistry and electrochemistry. Research programmes sponsored by industry and the Australian Research Council have led to significant commercial developments.