Continuous synthesis of atomically dispersed Rh supported on MgAl2O4
using two-stage microreactor
Single-atom catalysts with optimal atom utilization and outstanding
activity have penetrated the frontier of heterogeneous catalysis.
However, the large-scale synthesis of this class of catalysts is still a
bottleneck for their industrialization. Herein, we suggest a two-stage
micro-dispersion approach to synthesize mesoporous MgAl2O4-supported
atomically dispersed Rh, which is more competitive than the batch method
for boosting the uniform dispersion of Rh. By increasing the Rh loading,
single-atom catalysts (SACs, < 0.05wt%), single-atom
catalysts + nanoparticle catalysts (0.05–0.17 wt%), and nanoparticle
catalyst (NPCs, 0.17–1.10 wt%) were obtained. For n-octane steam
reforming, the turnover frequency of the SAC (0.01 wt%) was
approximately 30 times that of the NPC (1.10 wt%), while the Rh amount
of the SAC was only 3% that of the NPC for the same fuel conversion.
Under a high-temperature (750 ℃) steam atmosphere for 15 h, the hydrogen
formation rate only declined from 25.1 to 23.8 mol/mol-C8H18.