活性炭载体预处理对Ru/C氨合成催化剂活性的影响

将活性炭在惰性气体保护下进行高温热处理，随后在 O2/N2体积比为10%条件下进行氧化处理。采用元素分析、物理吸附和XRD方法，考察了不同处理后炭载体的化学组分、表面织构和物相变化。以不同预处理的活性炭为载体，制备了钡助催钌催化剂，在425 ℃,10.0MPa和10 000 h^－1条件下进行氨合成活性测试。结果表明，1 800 ℃热处理导致活性炭部分石墨化，能有效消除非炭成分，同时炭载体的比孔容下降了90%。随后的氧化处理能使炭载体比表面得到有效的恢复，以扩孔处理的炭为载体制备的钌催化剂能够使活性金属在载体中均匀分散，制备出高活性的氨合成钌催化剂。

Effects of pretreatment of activated carbon on activity of Ru/C ammonia synthesis catalysts

Activated carbon was pretreated at 1 800 ℃ in an atmosphere of inert gas, followed by oxidizing treatment in 10% O2/N2. Composition, surface texture and phase transformation of the treated activated carbon supportswere characterized by elemental analysis, physical adsorption and X-ray diffraction. Ba-promoted ruthenium catalysts were prepared using pretreated carbon supports. Activity of the catalysts for ammonia synthesis were tested under 425 ℃, 10.0 MPa and 10 000 h^－1. It was found that the treatment at 1800 ℃ effectively removed impurities from the carbon supports and led to partial graphitization of carbon supports and a drastic decline in their specific pore volume by about 90% . Surface area of the graphited carbon supports was restored effectively by subsequent oxidizing treatment. The catalyst supported on the activated carbon supports treated at 1800 ℃ followed by oxidizing treatment resulted in uniform dispersion of the active metal and exhibited high activity for ammonia synthesis.