泡沫SiC负载钴基结构化催化剂的制备及其催化性能

PREPARATION AND CATALYTIC PROPERTIES OF SiC FOAM SUPPORTED Co-BASED STRUCTURED CATALYSTS

以氨酚醛树脂为黏合剂,将掺Al的Co3O4粉末负载在SiC泡沫上,再经H2还原制备出SiC负载的钴基结构化催化剂.采用XRD,SEM,N2吸附-脱附和H2吸附等手段,研究了还原温度对涂层中Co晶粒的大小、相转化、微观结构以及吸附特性的影响,并以NaBH4水解放氢反应为探针反应,研究了不同条件下制备的钴基结构化催化剂的催化活性.结果表明,随着还原温度的升高,泡沫SiC表面涂层中活性组分Co的颗粒尺寸不断增大,结晶性增强.在120℃时,活性组分颗粒表面的H2化学等温吸附量随着还原温度的升高而降低,其催化活性也呈现降低趋势.当还原温度为400℃时,其催化NaBH4水解放氢的速率最大,可达48.38 mL/(g·min).

Co-based structured catalysts were prepared by coating Al-doped Co3O4powder on SiC foam support using phenolic resin as the adhesion agent, followed by H2reduction at moderate temperatures. XRD, SEM, N2adsorption-desorption and H2adsorption measurement were used to characterize the evolution of crystalline size of Co particles, morphology and phase assemblage of the coatings and the H2adsorption capacities of the structured catalysts obtained at different reduction temperatures. The catalytic properties of the prepared Co-based structured catalysts were evaluated by taking the hydrolysis of NaBH4as the model hydrogen generation reaction. Growing of the active Co particles in the coating as accompanied by the increase of crystallinity was observed with the increase of reduction temperature, which resulted in decreased chemical adsorption capacity of H2at 120 ℃ and catalytic activity towards hydrogen generation rate. The highest hydrogen generation rate of 48.38 mL/（g· min） was achieved at the reduction temperature of 400 ℃.