TiO2 (B) nanotubes with ultrathin shell for highly efficient photocatalytic fixation of nitrogen

Abstract

Abstract Photocatalytic fixation of nitrogen under the mild condition is a green and promising ammonia synthesis strategy, which however is still a big challenge due to the high activation energy for nitrogen. Herein, we report the photocatalytic fixation of nitrogen on TiO2 (B) nanotubes with large specific surface area (344m2/g), the ultrathin shell and submicrometer-sized cavity (ca. 250 nm). A high yield of 106.6 μmolg−1\u2009h−1 for NH3 under simulated sunlight irradiation was achieved at room temperature, which is 1.61 times the yield on TiO2 nanosheets. Based on the results from EPR, photoluminescence and photo-electrochemical analyses, the improved activity is attributed to the efficient nitrogen activation by the abundant surface defects and the enhanced light utilization on nanotube with the multiple light-scattering effect. Moreover, the photocatalytic activity of TiO2 (B) nanotubes can be well preserved for 4 cycles. This study provides a new approach for rational designing of efficient photocatalysts toward stable and robust nitrogen fixation in mild conditions.