Photocatalytic Nox Removal Using Tantalum Oxide Nanoparticles: A Benign Pathway

A wet chemical-synthesized high surface area ultrafine Ta2O5 nanoparticle and its application to NOx control is reported. The as-synthesized photocatalyst is characterized using powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), transient absorption spectroscopy (TAS), UV-vis diffuse reflectance spectroscopy, and N-2 adsorption (BET). The catalytic performance of these Ta2O5 nanoparticles was evaluated towards the photodegradation of nitrogen oxides (NOx) under UV-vis irradiation at room temperature. In comparison to the commercial TiO2 (Aeroxide P25 powder: 20 % rutile/80 % anatase, 50 m(2)/g), traditionally considered state-of-the-art material for the NOx degradation, as-synthesized Ta2O5 (41 m(2)/g specific surface area) nanoparticles offers NOx remediation with minimal toxic NO2 and excellent stability under UV irradiation. A 2-fold increase in the UV-photonic-efficiency (similar to 0.64 %) of Ta2O5 is observed compared to TiO2 P25 (similar to 0.30 %). NO conversion using Ta2O5 was noted to be 18.6 % compared to 8.8 % for TiO2. The UV-vis photocatalytic activity is explained on the basis of the band structure modulation of Ta2O5 due to the intrinsic defects introduced during the synthesis of the material.