Preparation and characterization of a novel Ni-doped TiO2 nanotube-modified inactive electrocatalytic electrode for the electrocatalytic degradation of phenol wastewater

A Ni-TiO2-NTs substrate and SnO2-Sb catalytic layer are formed on a Ni-Ti surface by the anodic oxidation method and sol-gel method, respectively, and a Ni-Ti/Ni-TiO2-NTs/SnO2-Sb electrode is successfully prepared for use as an electrocatalytic oxidation anode for wastewater treatment. Scanning electron microscopy (SEM) analysis shows that the Ni-TiO2-NTs base layer has a highly ordered and vertically formed nanotube array morphology, and the SnO2-Sb catalyst layer has a uniform and dense nanoparticle morphology. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses show that the base layer is made of Ni-TiO2 and the catalyst layer consists of SnO2-Sb. Electrochemical analysis shows that the oxygen evolution potential (OEP) of the electrode is increased to 2.3 V, and the working life is extended to 653 h. Using phenol as the treatment target, the phenol degradation rate reaches 87% in 3 h, and the COD removal rate reaches 54.2%. Compared with the traditional Ti/SnO2-Sb electrode, the current efficiency increases by 1.57 times, and the energy consumption decreased by 59.92%. Therefore, the Ni-Ti/Ni-TiO2-NTs/SnO2-Sb electrode is a promising electrochemical anode material for the treatment of phenol wastewater.