Photocatalytic Decomposition of Glycerol Solution on TiO2 Nanotube Arrays (TNTA) doped with C and N to Produce Hydrogen

Abstract

Carbon and Nitrogen-doped TNTA were synthesized by in-situ anodic oxidation of Ti using glycerol containing NH4F followed by annealing with 20% H2/Argon at 500 oC. Variation water content in the electrolyte solution (25 and 37.5 v%) and time of anodic oxidation (1, 2, 4 and 6 h) that influence the morphology of TNTA and H2 produced was examined. At water content 37.5 v% in the electrolyte solution, FESEM results indicated that the disorder with not vertically oriented of the tube were observed. For water content 25 v%, TNTA with average inner diameters of 81 to 105 nm, wall thicknesses from 15 to 27 nm and lengths from 882 to 1705 nm were synthesized for 1-6 h anodization. Morphology of TNTA such as well developed, vertically oriented, ordered and long could influence photon absorption and, therefore, influence the accumulative H2 production. The result indicated that the average inner diameter of the tubes increase as anodic oxidation time increased up to 6 h, on the other hand, the tube length reached the maximum at 4 h anodic oxidation. TNTA that anodized for 2 h, water content in the electrolyte solution 25 v% with average tube length 1570 nm showed the highest accumulative H2 production (47 mmol/m2 photocatalyst).