Enhancing the stability and electrocatalytic activity of Ti-based PbO2 anodes by introduction of an arc-sprayed TiN interlayer

Abstract

Ti/TiN/PbO2 electrodes were prepared using an arc-sprayed TiN interlayer on Ti substrates, followed by the anodic electrodeposition of a PbO2 catalytic surface layer on it. In order to investigate the positive effect of the TiN interlayer on the stability and electrocatalytic activity of the anodes, microstructural, surface roughness, adhesion evaluation, accelerated life and electrochemical performance tests and electrooxidation experiments of phenol simulated wastewater were conducted and compared with Ti/PbO2 anodes without the interlayer. The experimental results demonstrated that the arc-sprayed TiN interlayer with a thickness of 140–180 μm had a higher surface roughness and hardness than that of its titanium substrate. The coatings forming the electrode were firmly bonded to the substrate. The conductivity of the Ti-based PbO2 anode containing the TiN interlayer was significantly improved. The PbO2 surface coating achieved a faster deposition rate and finer grains, which produce a number of anode active sites and the electrocatalytic performance was boosted with a removal rate of phenol of up to 85.2%, which was higher than that of Ti/PbO2 by 30.6%. Simultaneously, the anode stability was also significantly enhanced, i.e., the Ti/TiN/PbO2 anode constructed by introducing the TiN interlayer exhibited excellent stability and electrocatalytic performance. The high-performance anode obtained relied not only on the presence of the arc-sprayed TiN interlayer, which significantly improved the overall physicochemical properties of the electrode, but also on the kinetic rate of the electrocrystallization growth of the refined PbO2 coating that was accelerated.