In the recent years, we made great efforts to develop: (1) efficient photocatalytic processes and photocatalysts for water splitting and methane conversion, (2) advanced materials for dye-sensitized solar cells and perovskite solar cells, and (3) efficient electrode materials with large accessible surface areas for supercapacitors. In this talk, I will discuss our recent success of efficient visible light photocatalytic conversion of methane to hydrogen, with emphasis on the design of processes and catalyst systems.