Ti3+self-doped and nitrogen-annealed TiO2 nanocone arrays photoanode for efficient visible-LED-light-driven photoelectrocatalytic degradation of sulfamethazine

Developing efficient, durable and visible-light-driven photoanode with excellent environmental adaptability is of great significance for photoelectrocatalytic (PEC) degradation of organic pollutants. In this work, a novel Ti3+ self-doped and nitrogen-annealed TiO2 nanocone arrays (Ti3+-TiO2NCs(N2)) photoanode was prepared for effi-ciently photoelectrocatalytic degradation of sulfamethazine (SMT) under visible light emitting diode (LED) irradiation, which obtained 98.68% removal for initial SMT concentration of 10 mg/L within 60 min. The visible light harvesting and charge transfer of TiO2NCs were significantly improved after nitrogen annealing treatment. Additionally, the introduction of moderate Ti3+ sites further lowered charge transport resistance and introduced a new impurity energy level, which efficiently accelerated the transmission of photogenerated carriers and then generated more h+ and active species to degrade pollutants. After 15 recycling degradation experiments, Ti3+- TiO2NCs(N2) still obtained more than 97% SMT removal, demonstrating highly durable. Also, it exhibited promising application prospect for treatment of real wastewaters (secondary effluent, pharmaceutical waste-water and mariculture wastewater).

Automated summary

A novel Ti3+ self-doped and nitrogen-annealed TiO2 nanocone arrays (Ti3+-TiO2NCs(N2)) photoanode was prepared for efficient photoelectrocatalytic degradation of sulfamethazine (SMT) under visible light. The visible light harvesting and charge transfer of TiO2 nanocones were significantly improved after nitrogen annealing treatment. The introduction of Ti3+ sites lowered charge transport resistance and introduced a new impurity energy level, resulting in accelerated transmission of photogenerated carriers and enhanced degradation of pollutants.