Photoelectrochemical Behavior of p-Type Boron Phosphide Photoelectrode in Acidic Solution

The photoelectrochemical behavior of p-type boron phosphide (p-BP) in acidic solution was investigated. The p-BP photocathode was stable in sulfuric acid solution under irradiation, and the band gap deduced from the photocurrent action spectrum in acidic solution was 2.0 eV. The gas evolved from p-BP photocathode was hydrogen which was obtained with a current efficiency of ca.100%. The photocurrent was markedly increased by suitable ruthenium treatment of the BP. A photoelectrochemical cell (PEC), Pt(H2)/0.5 M H2SO4(1 M=1 mol dm−3)/ /0.5 M H2SO4/p-BP, was shown to have an open-circuit photovoltage of 0.45 V and a fill factor of 0.25.