Photoelectrocatalytic effect of unbalanced RF magnetron sputtered TiO2 thin film on ITO-coated patterned SiO2 nanocone arrays

TiO2 has displayed potential for improved catalytic activity using a newly designed morphological system. Herein, a new catalytic system of SiO2/ITO/TiO2 nanocone array structures with unbalanced RF sputtering deposition was developed and demonstrated for photoelectrocatalytic activity. The array structures were fabricated using a soft nanolithography technique with a SiO2 sphere-patterned polydimethylsiloxane stamp. TiO2 films were coated on the ITO-coated SiO2 nanocones using unbalanced RF magnetron sputtering with various external magnetic fields applied by a solenoid. The nanostructures were examined using scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction crystallography, and X-ray photoelectron spectroscopy. The photocurrent response in water splitting was found to be increased by 400% for TiO2 films on nano-patterned arrays, compared with that on a flat surface. An additional increase in photocatalytic activity was achieved via TiO2 film deposition with an external magnetic field of 6 mT. This dramatic enhancement was attributed to the surface active sites created by the additional applied magnetic field and the increased surface area of the nanocone arrays.