This book provides expert techniques for extracting hydrogen from water using transition metal oxides as catalysts. The basic processes of electrochemistry and photocatalysis for hydrogen production are described along with photocatalytic reactions and semiconductor photocatalysts, particularly transition metal oxides. This in-depth guide illustrates the corresponding crystal structure vs. electronic structure and optical properties vs. light absorption of transition metal oxides. Impurity and doped photocatalysts, integrated organic and inorganic systems, surface and interface chemistry, and nanostructure and morphology in photocatalysis applications are all addressed. This comprehensive resource introduces soft x-ray absorption (XAS), soft x-ray emission spectroscopy (XES), and resonant inelastic soft x-ray scattering (RIXS), followed by a description of instrumentation.