Defect-induced growth of MoS₂ nanosheets on selectively etched SiC nanowires aerogel for efficient electrocatalytic hydrogen evolution

Exploring the cost-effective electrocatalyst for efficient hydrogen evolution is crucial in clean energy systems. However, the design and fabrication of catalytic materials with well-defined nanostructure and high activity remain a grand challenge. Herein, SiC nanowires aerogel was selectively acid-etched along stacking faults to produce significant surface defects, and MoS₂ nanosheets were nucleated and grown on SiC induced by these defects. Under different etching conditions, the SiC nanowires evolved into jagged, pagoda-like structures or nanosheets, respectively. The composites with MoS₂ nanosheets on jagged SiC nanowires possess optimal electrocatalytic performance for hydrogen evolution with a low overpotential (187 mV) at a current density of 10 mA/cm² and excellent stability, which is attributed to the special well-defined nanostructure of MoS₂/SiC. In the composites, the exposed crystal planes of jagged SiC nanowires can activate water dissociation, while the MoS₂ nanosheets on etched SiC nanowires are conducive to interfacial electron transport and the exposure of catalytically active sties, and the three-dimensional network structure of aerogel provides efficient channels for electron and reactant transport. Thus, this study offers a novel strategy to design efficient aerogel electrocatalysts via fine assembly of nanostructures.