Pt/TiO_2催化剂的制备及其在氨催化氧化中的应用

Preparation and Application of Core-shell Pt/TiO_2 Catalyst for Ammonia Oxidation Process

二氧化钛具有优良的光催化性能，以其为载体通过光催化还原沉积可在其表面实现单质金属活性组分负载．选择二氧化钛颗粒为载体，通过紫外光照射在二氧化钛颗粒表面还原沉积铂单质，形成Pt／TiO2负载型催化剂，并将该新型催化剂用于氨催化氧化反应．所制备的Pt／TiO2催化剂铂负载量减为0．2gpt／gTiO2，比表面积增达10mg／g．以该催化剂催化氨氧化反应，氨转化率在600～700℃即可达100％，低于目前硝酸工业中氨氧化反应温度800～900℃，也低于PtO：升华温度850℃．该催化剂经400h连续反应，其铂载量、及催化活性均无降低，具有工、Ik应用前景．

Titanium dioxide is an excellent photocatalyst, which can be utilized to load pure metal on its surface with photocatalytic reduction deposition process. In this study, pure metallic platinum was loaded on the surface of TiO2 particles with UV light irradiation to construct Pt/TiO2 catalyst for ammonia oxidation process. The Pt loading of catalyst is decreased to about 0.2 gpt/gTiO2, ant specific surface area is as large as 10 m2/g. With such catalyst, the ammonia conversion in ammonia oxidation process can reach 100% at 600 -700 ℃ , which is lower than the application temperature in present nitric acid industry, 800 - 900℃, and the sublimation temperature of PtO2, 850 ℃. Furthermore, there is no platinum loss and reaction active reduction of catalysts for 400 hours＇ continuous running. Therefore, this Pt/ TiO2 catalyst has exhibits a valuable application prospect of precious metal in nitric acid industry.