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采用乙酰丙酮钯为前驱体通过浸渍-热分解法制备了钯含量为45.3%的载钯硅藻土(Pd/K)复合材料,并通过冷/热循环、PCT,XRD及SEM对其进行吸/放氢循环性能和抗粉化性能分析。循环性能分析表明:40℃时Pd/K材料在30 s内已基本吸氢饱和,最大吸氢量为0.689%(质量分数)。初始250～380μm的Pd/K复合材料在2000次40℃吸氢/180℃放氢的吸放氢循环过程中,吸氢平衡压、吸氢量及吸氢速率均没有明显的衰减;但是,2000次循环后,复合材料150μm以下的样品占17.6%。物相和微观形貌分析表明:Pd/K复合材料由Pd和SiO2组成;复合材料的表面钯含量较高,经过热处理,其表面钯长大,形成钯膜,但该钯膜存在较多裂纹,致使其在吸/放氢过程中容易从复合材料颗粒表面脱落;Pd/K复合材料粉化主要是由其表面富钯层的脱落引起的。
Palladium-loaded diatomaceous earth (Pd / K) composites with 45.3% palladium content were prepared by impregnation-thermal decomposition using palladium acetylacetonate as precursors and were subjected to cooling / thermal cycling, PCT, XRD and SEM / Hydrogen cycle performance and anti-chalking performance analysis. The cycling performance analysis shows that the Pd / K material has basically saturated with hydrogen at 40 ℃ and the maximum hydrogen absorption is 0.689% (mass fraction). In the initial hydrogen absorption and desorption cycles of Pd / K composite material with 250-380μm at 2000 ℃ at 40 ℃ and hydrogen at 180 ℃, the hydrogen equilibrium pressure, hydrogen absorption capacity and hydrogen absorption rate did not decrease obviously. However, After 2000 cycles, the composite samples with the size of 150μm accounted for 17.6%. The phase and microstructure analysis showed that Pd / K composites consisted of Pd and SiO2. The Pd content of the composites was higher than that of the Pd / K composites. After the heat treatment, the surface palladium grew up to form a Pd film. However, , Which makes it easy to fall off from the surface of composite particles during the process of absorption / desorption. The Pd / K composite powder is mainly caused by the exfoliation of palladium-rich layer on the surface.