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采用浸渍法制备不同质量分数的CaO改性Al2O3催化剂(CaO-Al2O3),进一步浸渍Ru制备钌基催化剂(Ru/CaOAl_2O_3),运用BET、TEM、NH3-TPD等手段对改性催化剂进行表征,并考察改性催化剂在DBD等离子体反应器中合成氨的活性。结果表明,CaO的添加使Al_2O_3催化剂比表面积提高,但达到一定量时开始下降。进一步负载Ru后比表面积有所增加,同时,CaO能提高Ru在催化剂上分散度。此外,CaO和Ru的添加还可以改变催化剂表面酸强度和酸量。CaO的添加可有效提高催化剂在DBD等离子反应器中合成氨的活性,但达到一定量后增加不明显。进一步负载Ru后催化剂活性又会提高,Ru/5%CaO-Al_2O_3活性最大,其NH3-TPD在200℃附近氨脱附强度最大又使其氨产率和能量产率在240℃附近达到最大。
The CaO-modified Al2O3 catalyst (CaO-Al2O3) with different mass fraction was prepared by impregnation method and Ru / CaOAl_2O_3 was further impregnated with Ru. The modified catalysts were characterized by BET, TEM and NH3-TPD The activity of modified catalyst for ammonia synthesis in DBD plasma reactor was investigated. The results showed that the addition of CaO increased the specific surface area of Al 2 O 3 catalyst, but decreased when it reached a certain amount. After further loading of Ru, the specific surface area increased, meanwhile, CaO could improve the dispersion of Ru on the catalyst. In addition, the addition of CaO and Ru can also change the surface acid strength and acid content of the catalyst. The addition of CaO can effectively improve the activity of catalyst for ammonia synthesis in the DBD plasma reactor, but the increase is not obvious after reaching a certain amount. The catalytic activity of Ru / 5% CaO-Al_2O_3 increases further after further loading of Ru, and the NH 3 -TPD has the highest ammonia desorption intensity near 200 ° C and maximizes the ammonia yield and energy yield around 240 ° C .