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(CMx) 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 CMx 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.