N掺杂TiO2的制备及其光催化降解四环素的性能研究OA

Photocatalysis is an effective method for degrading tetracycline(TC),with photocatalytic materials serving as the core component of this process.Titanium dioxide(TiO2)is a highly efficient and environmentally friendly photocatalytic material.However,it suffers from rapid recombination of photogenerated carriers and a narrow ultraviolet light response range.To address these limitations,this study employed a gradient nitrogen(N)-doping strategy to modify sea-urchin-like TiO2.An in situ hydrothermal method was utilized to construct N-doped TiO2 materials,systematically elucidating the regulatory effects of N-doping concentration on the structure and performance of photocatalyst.Experimental result indicate that when the nitrogen-to-titanium ratio(nN∶nTi)is 5,the prepared photocatalyst(5N-TiO2)exhibits the best photocatalytic performance,achieving a 64%degradation rate for TC under 120 min of visible light irradiation.This represents a 137%enhancement compared to undoped TiO2.Characterization analysis reveals that 5N-TiO2,rich in Ti3+and oxygen vacancies,synergistically narrows the band gap of TiO2 from 3.07 eV to 2.60 eV,and significantly improves the separation rate of photogenerated carriers.However,further increasing the N-doping concentration level shows that excessive N forms electron-hole recombination centers,thereby reducing carrier lifetime.Consequently,the photocatalytic performance of 10N-TiO2(nN∶nTi=10)decrease to 41%of that of undoped TiO2.