SiO2纳米粉掺杂对薄膜光催化剂结构和活性的影响

针对固定膜光催化剂吸附能力差的缺陷,在催化剂的涂覆溶胶中掺杂具有较大比表面积的SiO₂纳米粉制备了一种新的TiO₂薄膜.通过X射线衍射(XRD)、扫描电镜(TEM)和红外光谱(FTIR)等手段对催化剂进行表征发现,催化剂的晶相以锐钛矿为主,并含有少量的金红石,平均晶粒尺寸为27nm左右.其中掺杂的SiO₂以十几到几十纳米的无定型团簇形式分散于薄膜中,除了能增大薄膜的表面积外,对TiO₂的晶体结构和表面基团等性质几乎没有影响.光催化降解试验表明,SiO₂掺杂后薄膜的活性大大改善,并受掺杂SiO₂的原始粒径和掺杂量影响很大.此外,该催化剂还具有很好的稳定性,在连续30多天的使用中,对活性艳红X-3B的去除率一直维持在80%左右,活性未见降低.

Influence of Doping the Nanosized SiO2 Powder on Structure and Activity of Photocatalytic Films

Regard to the poor adsorbability of the fixing film photocatalyst,a new TiO₂ thin film by doping the nanosized SiO₂ powder with large specific surface area into sol for coating film was prepared.Accoring to the results of characterization by XRD,SEM,FTIR techniques,it was found that the films were mainly anatase structrue,containing a little rutile and its mean crystallite size was about 27nm.And doped SiO₂ was dispersed into films forming the amorphous cluster with the size form more than ten nanometers to scores of nanometers.The doping of SiO₂ had no effect on the crystal structure and the surficial group of TiO₂,except for increassing specific surface area.The result of photocatalytic degradation showed that activity of the film doped by SiO₂ largely increased and was greatly influenced by the size and amount of doped SiO₂.Besides,this photocatalyst also had very good stability.During the course of continuous experiment for more than 30 days,removal efficiency of reactive brilliant red X-3B was kept at about 80% all the time.