Bamboo-like MnO2/TiO2 Nanotube Arrays with Enhanced Photocatalytic Degradation

In this paper, the photocatalytic degradation of methyl orange solution by MnO2/TiO2 nanotube arrays (NTAs) with different structure was studied. Initially, bamboo-like TiO2 NTAs with folded tube walls were synthesized using the anodic oxidation method. Subsequently, MnO2 nanowires/TiO2 NTAs and MnO2 nanoparticles/TiO2 NTAs were prepared via high-temperature and low-temperature hydrothermal methods, respectively. Photocurrent-time transient tests revealed that MnO2 nanoparticles/TiO2 NTAs produced by the low-temperature hydrothermal method exhibited a relatively good photocurrent response. All the deposited MnO2/TiO2 bamboo-like nanotube nanocomposites were tested for photocatalytic decomposition under different pH and light conditions. The results showed that MnO2 could adsorb and degrade methyl orange in the absence of light and acidity, and the degradation degree was proportional to the concentrations of Mn. MnO2 was stimulated to produce photogenic electrons, which migrated to the surface of the TiO2 and extended the life of photogenic charge carriers.