Fabrication of the high efficient novel SiC foam based 3D metal oxide anodes with long life to improve electrocatalytic oxidation performance

The SiC foam is a promising electrode substrate material because of its huge specific surface area and low price. The novel three dimensions (3D)-PbO2 and 3D-SnO2-Sb anodes using SiC foam as a substrate were first prepared to reduce the energy consumption of wastewater electrochemical oxidation treatment. The results of the elec-trochemical degradation of alizarin red S (ARS) in a flow-through reactor depicted that the ARS and chemical oxygen demand (COD) degradation rate constants of 60 pores per inch (PPI)-SiC/SnO2-Sb anode are 8 and 1.82 times that of the costly BDD electrode. For 60 PPI-SiC/SnO2-Sb/PbO2 anode, it is 10.12 and 1.35 times higher. The 3D-SiC/SnO2-Sb anode has a 142-218 times longer lifetime than that of the flat-Ti/SnO2-Sb electrode. Its lifetime is also obviously longer than that of the SnO2 electrode with the addition of an intermediate layer or advanced materials modified in the reported literature. A new failure mechanism of the 3D-SiC-based electrodes is elaborated which is different from the Ti-based electrodes. An accurate fluid model is constructed based on the micro-CT and CFD simulation to study the enhancement mechanism of the flow field. The results show that the turbulent kinetic energy and vorticity of the reactor are 3-6 times higher than that with 2D electrodes. The residence time distribution shows that the flow field of the 3D electrode exhibits a more approximate plug flow with no dead zones. Due to their high performance and long life, 3D-SiC-based SnO2-Sb and PbO2 anodes have good prospects for commercial applications.