Crystal Facet Control for the Stability of p-Cu<inf>2</inf>O Nanoneedles as Photocathode for Photoelectrochemical Activity

Controlled synthesis of single crystalline cuprous oxide (Cu2O) nanoneedles with {111} exposed facets is achieved on copper foil and the same film is used as photocathode for photo-electrochemical water splitting. It shows excellent performance as reflected by the current density of ∼1.5 mA/cm2 photocurrent at 0V vs. RHE in 50 mM Na2SO4 having pH ∼6.5. This performance shows ∼40% stability upto 1 hr of exposure to light. We attribute this photocurrent and stability performance to the exposed (111) facets.