The application of elastic strain is a promising approach for tuning bandgap of semiconductors; however, the attainment of a simple method for introducing strain has been a major challenge. Here, martensitic surface relief of FeNiCoTi substrate was utilized to tensilely strain TiO2 nanofilm successfully. The elastic strain effects of photocatalysis were also investigated. It was showed that tensile strain reduced the bandgap of TiO2 nanofilm by 50 meV and contributed to a 33.8% faster photodegradation rate of methyl orange, also the photocurrent of the water oxidation reaction of strained TiO2 was 1.4 times as high as that of unstrained nanofilm. (C) 2016 Elsevier B.V. All rights reserved.