欢迎访问《环境科学学报》编辑部网站！

快速检索			高级检索

环境化学

摘要：采用浸渍法在最佳制备条件下制备了新型Cr-Ce/TiO₂催化剂,并对催化剂进行了BET和XRD表征.同时,考察了反应温度、H₂O和SO₂对该催化剂催化氧化NO性能的影响,并对中毒催化剂进行了FT-IR分析,讨论了中毒机理.结果表明,Cr-Ce/TiO₂催化剂具有良好的NO氧化活性,在空速为10000h^-1、O₂体积分数8%(φ)、NO进口体积分数700×10^-6条件下,反应温度250℃时NO转化率可达到59.7%,330℃时NO转化率可达到最大值80.7%.单独加入10%(φ)H₂O或300×10^-6(φ)SO₂都可使催化剂活性降低,但在较高温度时影响较小.330℃下单独通入SO₂和同时通入H₂O与SO₂10h后,由于催化剂表面生成了少量硫酸盐和亚硫酸盐,活性下降并维持在62.4%左右,能够满足对NO_x进行高效吸收的要求;停止通入H₂O和SO₂后,催化剂活性恢复到71.6%,加热处理后活性能进一步恢复到78.5%.该催化剂具有比文献中报道的其它NO氧化催化剂更强的抗H₂O和SO₂毒化能力.

Abstract：Chromium-cerium catalysts supported on TiO₂ was prepared by impregnation under the optimum conditions and characterized by X-ray diffraction (XRD),and specific surface area measurement (BET). The effects of reaction temperature,H₂Oand SO₂ on catalytic oxidation of NO were investigated. The deactivation mechanisms in the presence of H₂O and SO₂ were analyzed by FT-IR. The results showed that Cr-Ce/TiO₂ yielded a 59.7% NO conversion at 250 ℃,and 80.7% at 330 ℃ when the space velocity was 10000 h^-1,O₂ and NOconcentrations were 8% (φ) and 700×10^-6 respectively. The activity of catalyst declined in the presence of only 10% (φ) H₂O or 300×10^-6 (φ) SO₂ but this negative effect could be counteracted by increasing the reaction temperature. After reacting for 10 h in the presence of only SO₂ or H₂Oand SO₂ together,a few sulfates and sulfites formed on the surface of the catalyst,and NOconversion was maintained at 62.4% which also satisfied the demands of highly efficient Absorption of NO_x. The activity of the deactivated catalyst could recover to 71.6% after removing H₂Oand SO₂ and further recover to 78.5% after heat treatment. The catalyst showed substantial poison resistance for H₂Oand SO₂ compared with other reported catalysts for NOoxidation.