F–B-codoping of anodized TiO2 nanotubes using chemical vapor deposition

Chemical vapor deposition (CVD) was firstly used to simultaneously codope fluorine and boron into TiO2 nanotubes anodized Ti in C2H2O4 · 2H2O + NH4F electrolyte. F–B-codoping was successfully carried out by annealing the anodized TiO2 nanotubes through CVD, as evidenced from XPS analysis. SEM images showed that the higher the annealing temperature, the greater structure damage of F–B-codoped sample. XRD results confirmed that annealing temperature had an influence on the phase structure and boron and fluorine impurities could retard anatase–rutile phase transition. F–B-codoped samples displayed remarkably strong absorption in both UV and visible range. Under visible-light irradiation, F–B-codoped samples showed the higher Iph and catalytic activity in methyl orange photoelectrodegradation than F-doped sample and B-doped sample. This showed a convincing evidence of F–B-codoping of TiO2 had an obvious synergistic effect on the enhancement of photocurrents and photoelectrocatalytic activity.