Direct harvesting of sunlight by photoelectrochemical (PEC) hydrogen generation offers a
carbon free and sustainable source of renewable energy. Since Fujishima and Honda’s
pioneering work [1], finding highly active photoanodic materials with efficient solar energy
conversion has become a topic of widespread interest [2, 3]. An ideal photoanodic material for
PEC hydrogen generation requires strong absorption of sunlight with suitable band gap and
band edges. Effective charge separation and transportation, as well as a good chemical stability
are also required.