短纤维状FeOOH催化剂的正仲氢催化转化性能OA

As a widely used catalyst for ortho-para hydrogen conversion,FeOOH is generally prepared by co-precipitation of inorganic iron salts with inorganic strong bases.However,this method has drawbacks such as large residual amounts of alkali metal cations and difficulty in regulating the specific surface area of the material.To solve these problems,an organic base,tetramethylammonium hydroxide(TMAH),was used to react with ferric chloride instead of NaOH for the preparation of FeOOH-T,which was applied to ortho-para hydrogen catalytic conversion.The catalyst was characterized by series of techniques,including XRD,N2 adsorption/desorption,HRTEM and ICP.The results show that the specific surface area of FeOOH-T can reach a maximum of 294 m2/g,and its microcrystalline grains are short fiber-like with a weakly crystalline phase.Using TMAH for FeOOH synthesis can effectively avoid large residual amount of alkali metal cations.After one-time washing,the Na⁺ content of the product is only 18%of that of commercial catalyst(FeOOH-F),which is conducive to significantly reducing the discharge of salt-containing wastewater.Mole fraction of para-hydrogen at the outlet of the device catalyzed by FeOOH-T and FeOOH-F is 92.06%and 88.61%,and the ortho-hydrogen conversion rate is 92.22%and 88.77%at 20 K and hydrogen flow rate of 2000 mL/min.Additionally,at the same conversion temperature,FeOOH-T shows the smallest decline in catalytic activity with increasing hydrogen flow rate,demonstrating overall optimal catalytic performance.