摘要
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/kieselguhr（Pd/K） composite with Pd of 45.3% was prepared by dipping-thermo decomposition with Pd（acac）2 as the precursor.Its hydrogenation/dehydrogenation cycles and anti-pulverization were studied by cool-heat cycles,PCT,XRD and SEM.The results of hydrogenation/dehydrogenation cycles showed that Pd/K composite were basically saturated in 30 s at 40 ℃,and its maximum hydrogen storage was 0.689%（mass fraction）.Pd/K composite with initial particle size of 250~380 μm had stable hydrogen storage capacity,plateau and kinetics during 2000 cycles under the condition of hydrogenation at 40 ℃ and dehydrogenation at 180 ℃,but the particle size less than 150 μm reached to 17.6%.The analysis of XRD and SEM indicated that Pd/K composite consisted of Pd and SiO2.Pd/K composite had higher content of Pd of surface of its particles.After heat treatment,the congregation of small particles of Pd carried out to form the film with porous micrograph.However,there were some cracks in the Pd film.As a result,Pd film easily detached from Pd/K composite particles during hydrogenation/dehydrogenation cycles.The high pulverization of Pd/K during the cycles was attributed to that the Pd was peeled from the surface of kieselguhr because of volume expansion.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2011年第2期238-243,共6页
Chinese Journal of Rare Metals
基金
国家科技部973项目资助(2010GB113003)
关键词
载钯硅藻土复合材料
热处理
循环性能
抗粉化
Pd/kieselguhr composite
heat treatment
cycle performance
anti-pulverization
