The major causes of global warming are mainly attributed to greenhouse gases such as carbon dioxide and methane. The conversion of the gases to renewable fuels has stirred interest for greenhouse gas mitigation and energy crises alleviations. The main objective was to develop the nanosized titania catalyst for selective carbon dioxide and methane reduction to fuels by using photoreactor. The photoreduction reported over titania nanoparticles and titania nanotube arrays. Response surface methodology was used to assess individual and interactive effects of important parameters on conversion. Finally, kinetic model using Langmuir-Hinshelwood developed to investigate photocatalytic reduction process, was found to fit well with the experimental data.