Research
Atomic Structure & Electrochemical Properties of Nanomaterials
Atomic structures of nanomaterials may be different from bulk materials due to surface effect and quantum effect, resulting in unique properties including catalytic activities. Short-range ordering in materials may affect physical properties including ion conduction, electrical conductivity and electrocatalytic activities. We use techniques like pair distribution function (PDF) analysis to help explain the impact of short-range ordering on materials properties.
Nanomaterials are of great importance for a variety of applications, such as fuel cells and batteries. We combine nanomaterials chemistry with rigorous atomic-scale structural analysis to explain the origin of materials properties.
Synthesis: We synthesize materials via solvothermal reactions (e.g., for metal organic frameworks)[1,2], low temperature reduction reactions (e.g., for conductive oxides)[3–5] and electrochemical reactions (e.g., for metal nanostructures)[6].
Analysis: We analyze atomic structures by general technique such as IR spectroscopy and X-ray diffraction as well as X-ray pair distribution functions (PDFs)[7]. In addition to the laboratory X-ray measurements, we often use synchrotron facilities. The data is analyzed using in-house programs as well as other major programs for the real-space Rietveld analysis and the Reverse Monte Carlo method. The structures are modeled via molecular mechanics simulations as well as density-functional theory (DFT) calculations.
Properties: We measure electrochemical properties using a range of setups including general techniques such as rotating disk electrode (RDE) and electrochemical impedance spectroscopy (EIS), in addition to more exotic methods such as measuring the ion/electron conductivities for single crystals [8,9]. In addition to these property measurements and structure analysis, we carry out a variety of technique such as synchrotron X-ray photoelectron spectroscopy to understand the mechanism [2,7].
References:
(1) Tominaka, S.; Coudert, F. X.; Dao, T. D.; Nagao, T.; Cheetham, A. K. J. Am. Chem. Soc. 2015, 137 (20), 6428.
(2) Tominaka, S.; Hamoudi, H.; Suga, T.; Bennett, T. D.; Cairns, A. B.; Cheetham, A. K. Chem. Sci. 2015, 6 (2), 1465.
(3) Tominaka, S. Inorg. Chem. 2012, 51 (19), 10136.
(4) Tominaka, S. Chem. Commun. 2012, 48 (64), 7949.
(5) Tominaka, S.; Tsujimoto, Y.; Matsushita, Y.; Yamaura, K. Angew. Chemie-International Ed. 2011, 50 (32), 7418.
(6) Tominaka, S. J. Mater. Chem. 2011, 21 (26), 9725.
(7) Tominaka, S.; Yoshikawa, H.; Matsushita, Y.; Cheetham, A. K. Mater. Horiz. 2014, 1, 106.
(8) Tominaka, S.; Cheetham, A. K. RSC Adv. 2014, 4 (97), 54382.
(9) Tominaka, S.; Henke, S.; Cheetham, A. K. Crystengcomm 2013, 15 (45), 9400.