Axially oriented tubercle vein and X-crossed sheet of N-Co₃O₄@C hierarchical mesoarchitectures as potential heterogeneous catalysts for methanol oxidation reaction

The ever-growing demand for environmentally friendly and efficient energy systems has stimulated significant efforts for the design of advanced electroactive fabrics. This paper reports facile control over heterogeneous mesoarchitectures of N-Co₃O₄@C unit blocks oriented along the c-axis arch. Three basic types of nanoscale architectures, namely, nanorod pellets (NRPs), nanoneedles (NNs), and crossed-X nanosheets (X-NSs), can be built in a vertical fashion along the c-axis orientations. The atomic structures of the developed N-Co₃O₄@C-NRP, NN, and X-NS catalysts were dominant along the dense exposure {1 1 2} plane, low-index crystal {0 0 1}, and {1 1 1} facets, respectively. Among all the nanoscale architectures, the NRPs revealed superior methanol oxidation reaction (MOR) in terms of oxidation current and onset potential, indicating the key role of the top-Co³⁺sites along the dense exposure crystal {1 1 2} facet. Results indicate that the heterogeneous N-Co₃O₄@C-NRP catalyst showed efficient electrochemical reactions and better long-term stability than commercial Pt/C catalyst.