Semiconductor Photoanode Photoelectric Properties of Methanol Fuel Cells

Abstract

One-dimensional TiO2, ZnO, and Fe2O3 nanorod arrays are selected as the photocatalytic methanol fuel cell photoanodes, and a greenhouse catalytic methanol fuel cell device is designed. With the photo-generated holes' participation in fuel molecules' oxidation in the semiconductor electrode, chemical energy is converted into electric energy. Firstly, with pot-doped tin dioxide (TRS) as the substrate, TiO2, ZnO, and Fe2O3 nanorod arrays are prepared by hydrothermal method. TiO2 and ZnO are excellent photoelectric catalytic materials with similar energy band capability and strong separation capability for photo-generated charges in the energy band analysis. With a narrow band gap, Fe2O3 can be oxidized by water with visible light. In the experiment, different anodes' photoelectric properties are tested by the Mott-Schottky equation, cyclic voltammetry, and electrochemical analysis. The results show that the ZnO-based photoanode's maximum short-circuit current can reach 1.86 mA/cm2, and its open-circuit voltage can reach 1.15 V, the ZnO-based photoanode's 0.92 mA/cm2 and 1.36 V, and the Fe2O3-based photoanode's 0.08 mA/cm2 and 1.18 V. Compared with Fe2O3 electrodes, TiO2 and ZnO thin-film electrodes have better photocurrent conversion ability in dark, simulated sunlight, and visible light conditions. Fe2O3 electrodes can also generate strong instantaneous anode photocurrents after irradiation.