Pt、N共掺杂TiO2在可见光下对三氯乙酸的催化降解作用

采用溶胶-凝胶法制备了氮掺杂纳米TiO₂(N-TiO₂), 并用光分解沉积法在N-TiO₂表面负载微量金属Pt(0.5％(w)), 形成铂-氮共掺杂纳米TiO₂(Pt/N-TiO₂). 实验结果表明, Pt 、N共掺杂纳米TiO₂紫外可见光吸收边带较纳米TiO₂红移约20 nm, 并在400～500 nm处有弱的吸收. Pt/N-TiO₂电极在可见光区的光电流约为纳米TiO₂电极的6倍. 以Pt/N-TiO₂为催化剂, 催化三氯乙酸(TCA)光降解反应, 室温下经可见光照射2 h后TCA降解率约为8％. N掺杂减小了TiO₂的禁带能隙, 使它在可见光区具有光催化活性, 适量Pt掺杂抑制了光生载流子的复合, 加速了电子界面传递速度, Pt、N共掺杂使两种效应相结合, 进一步提高了光催化反应性能.

Titanium Dioxide Nanoparticles Codoped with Pt and N for Photodegradation of Cl3CCOOH

Nanoparticles of titanium dioxide doped with nitrogen(N-TiO2) were syn thesized using sol-gel method. Nano-TiO2 codoped with platinum and nitrogen(Pt/N-TiO2) was prepared by photolys is-deposition of H2PtCl6 on N-TiO2 (0.5% (w) Pt). The onset of the absorption sp ectrum of Pt/N-TiO2 has a 20 nm red-shift and a weak absorption in the wavelengt h region from 400 to 500 nm compared with the spectrum of the non-doped catalyst . The photocurrent of Pt/N-TiO2 electrode is five times higher than that of TiO2 electrode. The photodegradation yield of trichloroacetic acid over Pt/N-TiO2 ca talyst is 8% under visible light irradiation for 2 h. Doping nitrogen in TiO2 r educes the band gap of anatase, which makes N-TiO2 possess catalytic activity in visible light region. Pt clusters precipitated on nano-TiO2 may retard the reco mbination of the photo-exited charge carriers and improve interfacial charge tra nsfer. Pt/N-TiO2 catalyst benefited from both of the effects.