Liu, GuanyuKaruturi, Siva KrishnaChen, HongjunSpiccia, LeoneTan, Hark HoeJagadish, ChennupatiWang, DunweiSimonov, A. N.Tricoli, Antonio2019-08-302211-2855http://hdl.handle.net/1885/165437Design of efficient photoelectrodes for water oxidation requires careful optimization of the morphology and structure of a photoactive material to maximize electrical conductivity and balance carrier diffusion length with light penetration depth. Hematite-based photoanodes can theoretically oxidize water at very high rates, as provided by the optimal band-gap, but their performance is limited by the poor charge transport and low charge separation efficiency. Herein, we have developed physically- and chemically-induced morphological and structural tuning procedures, viz. capillary-force-induced self-assembly and corrosion followed by regrowth, which enable significant improvements in the performance of the hematite photoanodes. Specifically, a 24-fold enhancement in the photocurrent density for water oxidation (1 M NaOH) at 1.23 V vs. reversible hydrogen electrode under simulated 1 sun (100 mW cm–2, AM1.5G solar spectrum) irradiation has been achieved. The capillary-force-induced self-assembly improves the crystallinity, promotes preferential orientation of the hematite along the [110] direction, and thereby enhances the electrical conductivity of the material. Subsequent dissolution and regrowth of the hematite nanostructures provide higher light absorption, improve photo-generated charge separation and facilitate photoelectrocatalytic kinetics resulting in the significantly higher photoelectrocatalytic activity. These broadly applicable insights provide a robust set of guidelines for the engineering of efficient photoelectrodes initially made of disordered structures for conversion of solar energy into renewable fuels.A.T. acknowledges the financial supports of the ARC DP150101939 grant and DE160100569. L.S. and A.N.S. are grateful for the financial support from Australian Research Council via the Center of Excellence for Electromaterials Science (CE140100012).application/pdfen-AU© 2018 Elsevier Ltd201810.1016/j.nanoen.2018.09.0482019-04-14