【摘要】 为推动ZrO₂-Al₂O₃在天然气汽车尾气净化催化剂中的实际应用,并阐明其制备条件对负载催化剂转化活性的影响机制,本工作以ZrO₂-Al₂O₃复合氧化物为载体,采用等体积浸渍法制备了Pd/ZrO₂-Al₂O₃催化剂,并在连续流动固定床反应器上研究了ZrO₂-Al₂O₃复合氧化物载体的制备对CH₄低温氧化活性的影响。结果表明:制备方法中,相比于浸渍法和胶溶法,沉淀法更能提高催化剂活性;锆源、铝源优选中,以Zr（NO₃）₄为锆源、拟薄水铝石为铝源时能获得较高的催化活性;组分配比中,以质量比ZrO₂:Al₂O₃=10:90的催化活性最高。XRD、低温N₂吸附、CO脉冲吸附的结构表征表明,ZrO₂-Al₂O₃复合氧化物的大的比表面积、孔容、孔径是促进贵金属Pd分散,提升催化剂低温CH₄转化活性的关键因素。更多还原

【Abstract】 In order to promote the practical application of ZrO₂-Al₂O₃ in the catalyst for natural gas vehicle exhaust purification, and to clarify the mechanism of the influence of preparation conditions on the conversion activity of the supported catalyst, the Pd/ZrO₂-Al₂O₃ catalysts supported by ZrO₂-Al₂O₃ composite oxides were prepared. The influence of the preparation of ZrO₂-Al₂O₃ composite oxides on the low temperature CH₄ oxidation activity of the catalysts were studied in a continuous flow fixed bed reactor. The results show that the precipitation method can improve the activity of catalyst more effectively than the impregnation method and the peptizing method. When Zr（NO₃）₄ is used as the zirconium precursor and boehmite as the aluminum precursor, high catalytic activity can be obtained. The activity of ω（Zr O₂）:ω（Al₂O₃）=10:90 is the highest in the series of catalysts with different proportions. The structure characterization of XRD, N₂ adsorption-desorption and CO pulse adsorption shows that the large specific surface area, pore volume and pore diameter of ZrO₂-Al₂O₃ composite oxides are the key factors to promote the dispersion of noble metal Pd and the conversion activity of catalyst CH₄ at low temperature.更多还原