Pd/Na2O/K2O/γ-Al2O3三元催化活性分析与评价

本文以浸渍法制备了活性γ-Al₂O₃涂层及Pd/Na₂O/K₂O/γ-Al₂O₃三元催化剂。考察了γ-Al₂O₃涂层比表面积随高温老化时间变化的规律。在实验室模拟尾气配气系统上，对Pd/Na₂O/K₂O/γ-Al₂O₃三元催化剂的起燃温度、抗高温老化及抗SO₂中毒能力进行了分析与评价。本文的γ-Al2O3涂层能经受1050℃的高温老化。Pd/Na₂O/K₂O/γ-Al₂O₃三元催化剂经900℃高温老化两次共13h后，其最大催化活性几乎不变，其老化样经600℃硫中毒1h后对CO和HC的催化转化率仍在75％以上。Pd/Na₂O/K₂O/γ-Al₂O₃新鲜样的起燃温度为280℃，二次老化样的起燃温度为320～350℃，具有很高三元催化活性。

Experimental assessment on activity of Pd/Na2O/K2O/γ-Al2O3 three-way catalyst

In this paper, active γ-Al₂O₃ coating and Pd/Na₂O/K₂O/γ-Al₂O₃ three way catalyst were prepared by impregnation method. Change in BET surface area of γ-Al₂O₃ with high-temperature aging time was investigated.Cold start temperature, thermal stability and tolerance to sulfur dioxide poisoning of the three-way catalyst(TWC) were tested on laboratory simulated emission control system. γ-Al₂O₃ coating prepared in this paper can tolerate 1050℃/6h thermal aging condition. After aging at 900℃ for totally 13 hours, activity of the catalyst sees nearly no deterioration. The aged samples retain 75％ of its initial activity after being poisoned by SO₂ at 600℃ for 1 hour. Cold start temperature of fresh catalysts is about 280℃. After two times of aging, the cold start temperature goes up to 320～350℃. It is concluded that Pd/Na₂O/K₂O/γ-Al₂O₃ TWC has satisfactorily high catalytic activity.