Mesoscopic Fabric Sheet Racks and Blocks as Catalysts with Efficiently Exposed Surfaces for Methanol and Ethanol Electrooxidation

Electrode designs based on sheet racks and blocks with multidiffuse groove spaces and enriched active sites and scales would promote the commercial applications of electroactive materials. A facile one-pot hydrothermal approach is reported to synthesize mesoscopic porous Co₃O₄ or hybrid graphene (GO)/Co₃O₄ sheet-on-sheet racks and blocks. Three basic types of sheet scalability racks can be built in vertical and nonstacked edge orientations, such as neat micro/nanogroove rooms, butterfly wing scales, and wall groves, leading to highly exposed surface converges and sites. In particular, the stacked GO/Co₃O₄ sheet-on-sheet blocks (GO/Co₃O₄ blocks) can be oriented in vertical tower buildings. The atomic structures of the developed Co₃O₄ catalysts are dominant along the highly dense {112/111} interfaces and single crystal {111} and {112} facets. The electrochemical performance of the mesoscopic porous Co₃O₄ catalyst toward methanol and ethanol electrooxidation is evaluated in alkaline conditions. The mesoscopic hybrid GO/Co₃O₄ racks reveal superior catalytic activity in terms of oxidation currents and onset potentials, indicating the effect of the synergetic role of active Co³⁺ sites along the densely exposed {112} facets, graphene counterparts, and hierarchically nonstacked sheet racks on the electroactive functionality. Results indicate that the mesoscopic GO/Co₃O₄ sheet catalyst is suitable for highly efficient electrochemical reactions.