Method for preparing hydrogen through photoanode photovoltaic battery coupled dual illumination fully photic driven decomposition of water

The invention relates to a method for preparing hydrogen through photoanode-photovoltaic battery coupled dual-illumination fully-photic-driven decomposition of water. Efficient decomposition of water is realized under sunlight illumination conditions by using coupling of a photoelectrocatalysis technology with a photovoltaic battery technology, adopting a water oxidation cocatalsyt modified semiconductor material as a photoanode, placing a proton reduction cocatalyst modified Si battery in an electrolyte as a photocathode, directly connecting the positive electrode of the Si battery with the anode through a lead and allowing the surface of the cathode to contact with the electrolyte. The method realizes fully photic driven decomposition of water without applied bias conditions, and the solar energy utilization efficiency STH of the method reaches 2.2% or above.