Pt/SiO₂-Al₂O₃ (Pt/SA) is commonly used as diesel oxidation catalysts (DOC) in industry, but it could be seriously deactivated caused by H₂O at long-term high temperature. In this paper, the inhibition mechanism of water on Pt/SA for NO oxidation was studied. The fresh Pt/SA (Pt/SA-F) was treated in an air flow with/without 10% H₂O at 700 °C for 10 h to obtain the hydrothermally/thermally aged catalysts named as Pt/SA-HA and -A, respectively. NO oxidation tests showed that Pt/SA-HA had lower activity than Pt/SA-A. A series of characterizations proved H₂O didn’t affected Pt states and support structure as they were similar over two aged catalyst. ¹H-NMR and In-situ DRIFTS testified that water deactivation was a result of the acidity loss of catalysts, which inhibited the decomposition and desorption of reaction intermediate, finally resulting in bad NO oxidation activity.

Pt / SiO ₂ -Al ₂ O ₃（Pt / SA）在工业上通常用作柴油氧化催化剂（DOC），但是在长期高温下，H ₂ O可能会使其严重失活。本文研究了水对Pt / SA的NO氧化抑制机理。将新鲜的Pt / SA（Pt / SA-F）在有/无10％H ₂ O的空气中于700°C的空气中处理10 小时，以获得名为Pt / SA-HA的水热/热老化催化剂，以及- A分别。NO氧化测试表明，Pt / SA-HA的活性低于Pt / SA-A。一系列表征证明H ₂ O不会影响Pt态和载体结构，因为它们在两个老化的催化剂上相似。^1个H-NMR和原位DRIFTS证明水失活是催化剂酸度损失的结果，其抑制了反应中间体的分解和解吸，最终导致不良的NO氧化活性。