双结构助剂对Ru/AC氨合成催化剂稳定性的影响

Effects of Dual Structure Promoters on Ru/AC Catalyst for Ammonia Synthesis

在高温高压条件下,单结构助剂的Ru-Ba-K/AC氨合成催化剂热稳定性较差,少量钐助剂的添加能显著的改善催化剂的稳定性.研究结果表明,在Ru-Ba-K/AC体系中,钐的添加量为0.5%时,钐的添加对催化剂活性影响很小,但稳定性显著增强;钐助剂的添加量超过1%以后,催化剂的稳定性进一步增强,但催化剂的活性显著下降.催化剂稳定性提高的主要原因可能是Sm掺杂显著提高催化剂结构助剂的抗烧结能力,而且钐的添加抑制了钌表面的氢吸附,提高了炭载体抗甲烷化能力.

The thermal stability of the Ru-Ba-K/AC catalysts promoted with single structural additive is poor for ammonia synthesis under the conditions of high temperature and high pressure, but the stability could be sufficient improved by addition of samarium promoter. Results show that the stability is remarkably improved and catalyst ac- tivity is weak affected when samarium content was 0.5%. The stability is further strengthen, but a significant re- duction of the catalytic activity is observed when samarium content is higher than 1%. The main reasons for signifi- cantly improved stability could be that the doping improved the sintering resistance of the structural additives, and methanation resistance by suppressing the hydrogen adsorption on the surface of the ruthenium.