Ortho to para hydrogen conversion over bimetallic iron and cobalt catalysts

The catalytic conversion of ortho-hydrogen (o-H₂) to para-hydrogen (p-H₂) serves as a crucial step in the storage of liquid hydrogen. A variety of iron-cobalt bimetallic catalysts (FCO) were synthesized using a precipitation method, incorporating diverse levels of Co doping into Fe-based catalysts. The effects of Co doping on the crystal structure, porosity, and magnetism of FCO catalysts were studied by XRD, N₂ physical adsorption, FTIR, XPS, and VSM analyses. The efficiency of ortho-para hydrogen conversion over FCO at 77 K was evaluated. It was found that the catalyst's lag coefficient was significantly improved by Co doping, leading to an increase of magnetic moment. The catalyst of FCO-5 with a Fe/(Fe + Co) molar ratio of 0.5 exhibited the highest activity in ortho-para hydrogen conversion. The corresponding conversion rate, outlet p-H₂ content, and the reaction rate constant were 99.2%, 49.7% and 291.7 mol·L^-1·s^-1, respectively, under a gas hourly space velocity of 5400 h^-1.