Micron-Scale Vertical MoS₂/Porous g-C₃N₄ Piezocatalyst via a Precursor’s Supramolecular Self-Template Architecture: Degradation and Hydrogen Evolution

Piezocatalysis can effectively harvest various kinds of mechanical energy with high entropy from the environment and drive some redox reactions without light irradiation, where MoS₂- and g-C₃N₄-based piezocatalysts are recent research hotspots. This study constructs an architecture of ordered melamine hydrochloride-cyanuric acid/MoO₄^2- supramolecular precursor via self-assembly, serving as a self-template for in situ tight growth of vertically aligned micron-scale MoS₂ on porous foam-like g-C₃N₄(CM<i>x</i>) under S vapor with a bioinspired rooting and sprouting-like process. Experiments, DFT calculations, and finite element simulations collectively confirm the high piezoresponse of the CM<i>x</i> with high exposure of active sites and enhanced mechanical energy collection. The vertical interfaces and built-in electric fields in the composite induce efficient charge carrier separation and transfer. The optimized CM0.77 efficiently degrades various organic dyes and antibiotic under dark ultrasound [rhodamine B (RhB): 0.47 s^-1, methyl orange (MO): 0.05 s^-1, methylene blue (MB): 0.21 s^-1, and tetracycline hydrochloride (TC): 0.03 s^-1] and achieves hydrogen evolution (2431 μmol·g^-1·h^-1). Under simulated water flow (10 L/min), the expanded CM0.77/Al₂O₃ porous foam ceramic (CM/alumina ceramic) purifier device degrades 95% of 400 mL of RhB within 25 min. The developed ordered vertical MoS₂/g-C₃N₄ piezocatalyst demonstrates rapid pollutant degradation and efficient hydrogen evolution under water flow and ultrasound, providing new insights for constructing multidimensional piezoelectric composites for environmental remediation and clean energy production.