Activated Carbon-Modified Porous Carbon Nitride Decorated with Molybdenum Disulfide for Enhanced Photocatalytic Degradation of Rhodamine B

Photocatalytic technology offers significant potential for pollutant remediation through efficient, cost-effective mineralization but faces inherent limitations, including catalyst agglomeration and rapid charge recombination. To address these challenges, we developed activated carbon-modified porous graphitic carbon nitride (APCN) synthesized through the co-polycondensation of dicyandiamide with NH4Cl and fir-wood-derived activated carbon (AC). The incorporated AC effectively prevented the agglomeration of carbon nitride frameworks, thereby enhancing the specific surface area (SBET) of APCN. This matrix was subsequently composited with hydrothermally prepared (1T/2H) mixed-phase MoS2 through ultrasonication, forming a MoS2/APCN heterostructure. Characterizations including Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and N2 adsorption–desorption isotherms (BET) confirmed that MoS2 was successfully loaded onto APCN via an ultrasonic synthesis method. The composite exhibited outstanding photocatalytic activity, degrading 95.5% RhB in 40 min (pH = 7) and 97.4% in 25 min (pH = 3.5), with 87.3% efficiency retention after four cycles (pH = 7). Crucially, AC enhanced visible-light absorption and functioned as an electron-mediating component. Photoelectrochemical analyses and radical-trapping experiments confirmed a direct Z-scheme charge transfer mechanism, wherein conductive AC accelerates electron transport and suppresses carrier recombination. This study establishes both an efficient RhB degradation photocatalyst and a sustainable strategy for valorizing agricultural waste in advanced material design.