Wind turbines are a green energy source that Taiwan has been endeavouring to develop in the past five years. Excellent onshore wind farms have already been developed; however, offshore development is inevitable because of Taiwan's limited land area. With regard to energy sustainability, operation and trouble-free maintenance of wind farms are essential. If damage to fan components can be mostly prevented, the operating cost and maintenance time would be considerably decreased; thus, remarkable economic benefits could be achieved. An appropriate coating can help a structure resist the stress of the working environment and improve its durability, resulting in lower maintenance cost and less staff being required to perform on-site repairs. Diatomaceous earth (DE) has been widely used to produce composite porous materials. In this study, epoxy resin and titanium dioxide were mixed with DE to increase the hydrophobicity of the surface of coatings and provide them photocatalytic self-cleaning ability. The ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate was also added to the coatings to prevent the corrosion of coated metallic material. This study employed thermal analysis to investigate the thermal stability of the coatings and the corrosion resistance of coated iron blocks. Finally, a self-made quartz container was connected to a volatile organic compound detector, and sun exposure was simulated using ultraviolet light. The results confirmed that the modified coating retained its functionality under the harsh working environment and can be applied to the surfaces of large machinery used in offshore wind turbine towers.