Changes of photoelectrocatalytic, electrocatalytic and pollutant degradation properties during the growth of β-PbO2 into black titanium oxide nanoarrays

Abstract

• Black TiO 2 nanoarrays (BTN) with excellent property was prepared. • Ti/BTN/β-PbO 2 (5 s) exhibited the best photoelectrocatalysis. • Ti/BTN/β-PbO 2 (30 min) possessed the best degradation capacity of pollutant. • The excellent activity was ascribed to the rapid transfer of electrons. • The excellent stability was due to interlocked structures. β-PbO 2 could be electrodeposited into the vertically arranged black titanium oxide nanoarrays (BTN) to prepare electrode (Ti/BTN/β-PbO 2 ) for advanced oxidation treatment. However, changes in photoelectrocatalysis and electrocatalysis of Ti/BTN/β-PbO 2 during β-PbO 2 deposition have never been studied synchronously. Herein, BTN with excellent mechanical property and conductivity was prepared. Then changes of photoelectrocatalytic, electrocatalytic and wastewater treatment properties of Ti/BTN/β-PbO 2 were recorded as a function of deposition time (0 s, 5 s, 10 s, 15 s, 20 s and 30 min). Results indicated that Ti/BTN/β-PbO 2 (5 s) exhibited the greatest photoelectrocatalysis. Ti/BTN/β-PbO 2 (30 min), as an electrocatalyst, demonstrated the lowest oxygen evolution potential, however, possessed the best ability to degrade pollutant. The colloidal PbO(OH) 2 of Ti/BTN/β-PbO 2 (30 min) played significant roles in generating electroreactive species of OH and O 3 , which were main electroreactive species for pollutant degradation in electrochemical wastewater treatment. Further research indicated that the better activity of Ti/BTN/β-PbO 2 (30 min) than that of Ti/β-PbO 2 (30 min) may be due to the vertical electrons transfer channel provided by BTN. Moreover, the excellent stability of Ti/BTN/β-PbO 2 depended on the interlocked structures formed between BTN and β-PbO 2 , and the anodic protection. This study provided simple methods for optimizing the photoelectrocatalysis of BTN or preparing Ti/BTN/β-PbO 2 with high electrocatalytic activity and stability, and furtherly explored the reasons of excellent activity and stability of Ti/BTN/β-PbO 2 .