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

Abstract

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 electrochemical 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.