Excellent visible light responsive photocatalytic behavior of N-doped TiO2 toward decontamination of organic pollutants

Abstract

In this work, N-doped TiO2 (N-TiO2) with ample and tunable OVs was successfully synthesized, deriving from facile hydrothermal method and baked in the NH3 atmosphere. N-doping boosts the amount of surface hydroxyl and superoxide (O2−) of TiO2, demonstrated by XPS and nitroblue tetrazolium (NBT)-O2− quantitative reaction. Rich and tunable OVs were confirmed by low temperature electron spin resonance (ESR) results, demonstrating that doping of N into TiO2 can definitely construct higher OVs than the reference TiO2. Surface photovoltage spectrum (SPS) test, fluorescence experiments and electrochemical measurements all display that N-TiO2 photocatalysts with OVs have a higher severance efficiency of photogenerated e-/h+ pairs than the pristine TiO2. Photocatalytic evaluation results exhibit that N-TiO2 photocatalysts demonstrate better performance than the reference TiO2 toward decontamination of rhodamine B and tetracycline. TiO2 treated in ammonia atmosphere for 1 h shows the highest photocatalytic property. The visible light responsive catalytic behavior of TiO2 treated in ammonia atmosphere for 1 h is much higher than that of commercial TiO2 (P25) and the pristine TiO2, separately. The ameliorated visible light behavior of N-TiO2 photocatalysts is attributable to rich oxygen vacancies produced through introducing N into TiO2 and the boosted severance of photoactivated e-/h+.