Facile ball-milling synthesis of carbon nitride Z-scheme heterojunction for dramatically enhanced photocatalytic degradation of environmental pollutants

The Z-scheme heterojunctions have garnered significant attention in photocatalysis due to their enhanced charge carrier separation and transport capabilities. In this study, a novel Z-scheme heterojunction composed of phosphorus-doped carbon nitride (P-C 3 N 4 ) and manganese-doped carbon nitride (Mn-C 3 N 4 ) was constructed via a simple and efficient ball milling method. Compared to the pristine g-C 3 N 4 , P-C 3 N 4 , and Mn-C 3 N 4 , the P-C 3 N 4 /Mn-C 3 N 4 Z-scheme heterojunction demonstrated a substantial improvement in photocatalytic performance. This enhancement is attributed to the optimized energy band alignment and intimate interface contact between the two components, which promote efficient charge carrier separation, accelerate electron transport, and improve interface stability. Experimental results showed that the P-C 3 N 4 /Mn-C 3 N 4 system achieved complete degradation (100 %) of Rhodamine B (RhB) and 91.1 % degradation of tetracycline hydrochloride (TC) within 60 min. Additionally, the system retained over 80 % of its catalytic activity after five cycles, suggesting its promising potential for industrial applications. This study provides a simple, cost-effective, and environmentally friendly approach, offering valuable insights for the design of Z-scheme heterojunctions and innovative C 3 N 4 -based photocatalysts.