Amorphous cobalt iron oxide nanoparticles with high magnetization intensity for spin conversion of hydrogen at 77K

Conversion of ortho-hydrogen (o-H2) to para-hydrogen (p-H2) is a necessary process in hydrogen liquefaction, and investigating the catalysts that accelerate conversion is significant. Herein we report the effect of Co/Fe ratio in cobalt iron oxide catalysts on conversion of o-H2 to p-H2 at 77 K, and use XRD, BET, and VSM to explore the influence of different Co/Fe ratios on internal crystal structure, pore size, and magnetization strength. It is concluded that the synergistic effect of crystal structure disorder (increase in active sites), small pores (decrease in distance between o-H2 and active sites), and high magnetization strength (larger torque upon) resulted in the optimal catalytic performance for CFO-3 [n(Co):n(Fe) = 3:10]. When the hydrogen flow is 100 mL min-1, the content of p-H2 in the converted hydrogen is 47.61%. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.