The development of efficient catalyst materials for water oxidation is bottleneck to construct artificial photosynthesis that is a promising future energy-providing system. We review the recent progress on development of IrOx electrocatalyst films for water oxidation based on our latest research works. A controlled fabrication approach of an efficient IrOx electrocatalyst films is introduced by a facile spin coating of a homogenous solution of Ir precursor complexes followed by simple annealing at different temperature. The composition and crystallinity of the IrOx film are tunable by a simple annealing treatment. The electrocatalytic properties of the IrOx film dramatically depended on annealing temperature are characterized to give the noticeably high performance at 300 degrees C annealing. A soft-template assisted technique using different polymer surfactants as structure directing agents (SDAs) is illustrated in the spin-coating procedure to reveal impacts of SDAs on nanostructures and electrocatalytic water oxidation performances of the IrOx films. The characterization of the first accessible channel-like open pore architecture of the ordered 2D-hexagonal mesoporous IrOx film is described by a facile one-pot strategy using Pluronic F127 as SDA. The novel controlled nanostructures including mesoporous architecture of IrOx improves electrocatalytic performance for water oxidation relative to a conventional nanoparticulate structure of IrOx coating. (C) 2019 Elsevier Ltd. All rights reserved.