Electrocatalytic oxidation of coal on Ti-supported metal oxides coupled with liquid catalysts for H2 production

Electrocatalytic oxidation of coal on Ti-supported metal/metal oxides coupled with liquid catalysts is systematically investigated as a method of producing hydrogen at the cathode. The composition of the liquid catalyst was varied to determine its effect on the coal electrolysis. A spectrum of byproducts from the coal oxidation at the anode was analyzed. The Ti-supported metal oxide electrodes were prepared by thermal decomposition and characterized by scanning electron microscopy (SEM). X-ray diffraction results show that the composition of the electrodes was Ti/Pt, Ti/RuO2, Ti/IrO2 and Ti/IrO2–RuO2. Coal oxidation tests on these electrodes indicate that Ti/IrO2 has the best electrocatalytic activity. Polarization curves reveal that redox catalysts, such as Fe3+, K3Fe(CN)6, KBr and V2O5, bridge the coal particles and the solid electrode surface, thus increasing the rates of coal oxidation. The dynamic transition of Fe3+/Fe2+ is proven by a KMnO4 titration experiment, and the possible catalytic mechanism is discussed. Product analysis shows that pure H2 is generated at the cathode and that CO2 is the main product at the anode.