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利用钛基复合金属氢氧化物作为前驱体,通过焙烧转化为钛基复合金属氧化物,作为光合成过氧化氢的催化剂.发现复合金属氧化物中的氧化锌晶相在合成过氧化氢反应中被原位溶蚀,逐步转变为TiO_2-ZnTiO_3相.复合金属氧化物与原位转化得到的TiO_2-ZnTiO_3都显示出比商品化的TiO_2(P25:80%锐钛矿和20%金红石混合相)更好的光合成过氧化氢性能.动力学分析表明,过氧化氢的生成由其生成速率与分解速率共同决定,TiO_2-ZnTiO_3作为催化剂时,过氧化氢的生成速率常数(K_f)是3.581μM/min,是复合金属氧化物作催化剂时(K_f=0.982μM/min)的3.65倍,是P25(K_f=0.852μM/min)的4.20倍.而相应的分解速率常数(K_d),TiO_2-ZnTiO_3(K_d=0.0472min~(-1))是复合金属氧化物(K_d=0.0119min~(-1))的3.97倍,是P25(K_d=0.0374min~(-1))的1.26倍.TiO_2-ZnTiO_3具有更大的生成速率常数和分解速率常数.因此,尽管TiO_2-ZnTiO_3在反应初期催化生成了更多的过氧化氢,但随着反应进行,TiO_2-ZnTiO_3催化合成的过氧化氢与复合金属氧化物达到几乎相同量,这表明催化剂的原位结构(物相)转变对反应动力学产生了影响,但并不显著改变过氧化氢的最终产量.抑制过氧化氢在催化剂表面的分解是提高其产量的重要途径.该工作加深了对钛基复合金属氧化物光催化合成过氧化氢的反应动力学认识,为钛基催化剂结构设计提供了一定指导.
The use of titanium-based composite metal hydroxide as a precursor, by conversion to a titanium-based composite metal oxide photocatalyst as a photocatalyst of hydrogen peroxide was found in the composite metal oxide zinc oxide crystal phase in the synthesis of hydrogen peroxide was Situ dissolution and gradually transformed into TiO_2-ZnTiO_3 phase.Compared with TiO_2-ZnTiO_3 obtained by in-situ conversion, the composite metal oxides showed better performance than commercial TiO_2 (P25: 80% anatase and 20% rutile mixed phase) The kinetic analysis shows that the formation rate of hydrogen peroxide is determined by its formation rate and decomposition rate. The formation rate constant of hydrogen peroxide (K_f) is 3.581μM / min when TiO_2-ZnTiO_3 is used as catalyst, (K_f = 0.982μM / min) and 4.20 times that of P25 (K_f = 0.852μM / min), while the corresponding decomposition rate constants (K_d), TiO_2-ZnTiO_3 (K_d = 0.0472min ~ (-1)) is 3.97 times that of the composite metal oxide (K_d = 0.0119min ~ (-1)), which is 1.26 times that of P25 (K_d = 0.0374min ~ (-1)) .TiO_2-ZnTiO_3 has more Large formation rate constants and decomposition rate constants.Therefore, although TiO 2 -ZnTiO 3 catalyzed in the early stage of reaction However, as the reaction progressed, the amount of hydrogen peroxide synthesized by TiO 2 -ZnTiO 3 was almost the same as that of the composite metal oxide, which indicated that the in-situ structure (phase) transition of catalyst affected the reaction kinetics , But did not change the final production of hydrogen peroxide significantly.Determination of hydrogen peroxide decomposition on the catalyst surface is an important way to improve its yield.This work deepens the titanium-based composite metal oxide photocatalytic synthesis of hydrogen peroxide reaction power Learn to learn, for titanium-based catalyst structure design provides a guide.