| The development of reliable non-precious metal oxide（Pb O2 and Mn O2）coated titanium anodes has become a common concern in the fields of electrochemical engineering,electro-oxidation water treatment and seawater electrolysis for hydrogen production.Ti-based Pb O2 and Mn O2 electrodes have the advantages of low cost,good mechanical processing performance and designability,however,the durability of the anodes prepared by direct coating is poor in service.Although the stability of anodes has been enhanced by introducing metal or metal oxide interlayer,it is still difficult to meet the basic requirements for reliable application in longer-term engineering.Besides,the electrocatalytic activity of the anodes needs to be further improved.Arc spraying is a simple,efficient and mature technology.Ti N layer with good conductivity,acid and alkali corrosion resistance can be prepared by arc spraying in the atmospheric environment.Therefore,in this study,on the one hand,Ti N interlayer is introduced into the Ti-based Pb O2 anode by arc spraying technology to prepare long-life and high-performance Ti-based Pb O2 anode material,which can promote the efficient and practical treatment of refractory wastewater by electro-oxidation technology,making it an important optional technology in water pollution control projects.On the other hand,low-cost Ti N made by arc spraying was used to replace the noble metal Ir O2 as an intermediate layer of Ti-based Mn O2 anode,and tungsten carbide nanoparticles with excellent electrical conductivity were used in the composite Mo-doped Mn O2 coating by co-deposition to enhance the comprehensive performance of the electrode and to advance the development and practicalization of electrolytic seawater direct hydrogen production technology.The main results obtained from the experimental study include:（1）The Ti/Ti N/Pb O2 electrode was prepared by arc spraying Ti N interlayer on the surface of the titanium substrate followed by anodic electrodeposition of Pb O2 catalytic surface layer,and the stability of the Ti/Ti N/Pb O2 electrode was significantly enhanced.This is attributed to the presence of the arc-sprayed Ti N interlayer,which resulted in a significant improvement in the physico-chemical properties of the electrode such as solid bonding,increased hardness,high surface roughness and enhanced electrical conductivity.The refinement of the crystalline Pb O2 coating electrodeposited on the surface of the arc-sprayed Ti N interlayer resulted in a faster growth kinetic rate and a thicker active coating.（2）The introduction of arc-sprayed Ti N interlayer can significantly enhance the catalytic performance of the Ti-based Pb O2 electrode,and the 3 h degradation of 100mg/L phenol simulated wastewater can result in 85.2%phenol removal,which is 30.6%higher than that of the Ti/Pb O2 anode.In terms of COD removal,the Ti/Ti N/Pb O2 anode can reach 49.3%after 3 h of electrolysis,which is 15.4%higher than that of the Ti/Pb O2anode.（3）The process of oxygen evolution electrolytic failure of Ti/Ti N/Pb O2 anodes introduced by the arc-sprayed Ti N interlayer can be divided into four stages:activation,stabilization,instability and failure.The anode failure is caused by the exposure of local Ti N interlayer due to the physicochemical dissolution of Pb O2 coating,but the strongly bonded Ti N interlayer does not dissolve and peel off.When the active oxygen reaches the titanium substrate through the exposed Ti N interlayer,it triggers local oxidation,which gradually spreads to the whole Ti substrate interface and finally generates a dense Ti O2 insulating film at the interface between the substrate and the interlayer,leading to the overall anode failure.（4）Ti/Ti N/(Mn1-xMox)O2+x-WC coated electrodes were obtained by arc spraying Ti N interlayer on the surface of Ti substrate,followed by composite anodic nanoelectrodeposition of WC and Mo-doped Mn O2 layer on it.Compared with the conventional Mn O2 anode with pyrolytic Ir O2 interlayer,the obtained anode shows excellent selectivity and stability of oxygen evolution and chlorine suppression because the Ti N interlayer can effectively block the erosion of active oxygen on the titanium substrate in electrolysis,and the Mo-doped Mn O2 composite is augmented by WC with excellent electrical conductivity.Compared with Ir O2 interlayer prepared by pyrolysis,the arc-sprayed Ti N interlayer has the advantages of significantly lower cost,simple and efficient fabrication. |
PDF Full Text Request