Photoelectrocatalytic conversion of biomethane and biogas to hydrogen over a nanostructured Ti/ TiO ₂ semiconductor

Abstract

This work describes the synthesis of Ti/TiO 2 nanotubes by anodic oxidation of a Ti plate, followed by calcination in a muffle furnace, and their application in the photoelectrocatalytic conversion of biomethane and biogas to hydrogen. Morphological and compositional analysis confirmed that TiO 2 nanotubes were formed on the Ti plate, with internal diameter of approximately 41.7 nm, tube wall thickness of 10 nm, and length of approximately 2.4 μm. Electrochemical characterization demonstrated photoactivity of the Ti/TiO 2 in the photoelectrocatalytic reactions, with lower recombination of e À /h + pairs in the presence of methane. The maximum values obtained for the conversion of biomethane and biogas using the Ti/TiO 2 nanotubes during 5 h of photoelectrocatalysis were 516.5 and 333.9 mmol of H 2 respectively. Investigation was made of the effects of parameters such as the applied potential and time on the photoelectrocatalytic conversion of CH 4 to H 2 .