Directly prepared Al-doped FeMoO4 materials from spent hydrogenation catalysts via a low-temperature green process

Abstract

Environmental-friendly recovery of critical metals from solid wastes directly for new energy materials received lots of concerns. In this paper, the FeMoO4(FMO) materials for new energy storage materials are directly prepared from spent hydrogenation catalysts by “low temperature sodium roasting-water leaching” process. The leaching rates after roasting of main metal element Mo, Al and Ni from wastes are: 91.8 %, 1.7 % and 0.1 %, respectively, then the leachate was directly generated Al-doped FMO materials (Mo/Al = 50:1). As for the application of lithium ion battery anode, the specific capacity is 363.5 mAh/g after 200 cycles, 55 % improvement compared with bare FMO. The tunable phase transformation by roasting temperature regulation is the core to achieve the selective water leaching of Mo, and the intrinsic mechanism have been investigated by calculation and experiments. Finally, the economic evaluation of the whole process shows that for every 1 kg of spent catalyst processed and made into FMO, a profit of $20.8 can be obtained, indicating promising economic benefits. This process provides an environmental technology route for the development of new energy industries under carbon neutrality goals.