Effects of the addition of surfactants on the direct fabrication of a CuFeO2/Fe photocathode by hydrothermal method

CuFeO2 is a prospective photocathode material for water or CO2 reduction, but satisfactory performance has not been achieved yet. This has been ascribed to the large size of the CuFeO2 particles obtained by growing a CuFeO2 film on an Fe substrate when using hydrothermal method for enhanced adhesion between film and substrate. This study evaluates the effect of adding oleic acid or acetic acid as surfactants in the hydrothermal fabrication process with the expectation of controlling the crystal growth. The investigation of the shape and the size of the obtained CuFeO2 particles by scanning electron microscopy and X-ray diffraction and the evaluation of the photoelectrochemical performance of the CuFeO2 photoelectrodes by electrical conductivity and photoelectrochemical measurements demonstrate that, although an increase in the particle surface area can be achieved, the performance is highly affected by the grain boundary resistance.