Hollow Carbon Nanorod Confined Single Atom Rh for Direct Formic Acid Electrooxidation

Nearly theoretical 100% atomic utilization (supposing each atom could serve as independent sites to play a role in catalyz) of single-atom catalysts (SACs) makes it highly promising for various applications. However, for most SACs, single-atom sites are trapped in a solid carbon matrix, which makes the inner parts hardly available for reaction. Herein, a hollow N-doped carbon confined single-atom Rh (Rh-SACs/HNCR) is developed via a coordination-template method. Both aberration-corrected scanning transmission electron microscopy and energy dispersive X-ray spectroscopy mapping confirm the uniform distribution of Rh single atoms. Owning to the unique hollow structure and effective carbon confinement, excessive conversion from pyridinic/pyrrolic N to graphic N is hindered. As a proof of concept, Rh-SACs/HNCR exhibits superior activity, stability, selectivity, and anti-poisoning capability in formic acid oxidation reaction compared with the counterpart Rh/C, Pd/C, and Pt/C catalysts. This work provides a powerful strategy for synthesizing hollow carbon confined single-atom catalysts apply in various energy-related systems.