Constructed palladium-anchored hollow-rod-like graphitic carbon nitride created rapid visible-light-driven debromination of hexabromocyclododecane

The high-efficiency photocatalytic debromination of hexabromocyclododecane (HBCD) as new POPs and discovery of involved mechanisms remain a challenge. Herein, challenging Pd-anchored hollow-rod-like-g-C 3 N 4 (Pd/HR-g-C 3 N 4 ) was constructed as visible-light-driven photocatalyst. Complete destruction of (±)-α, (±)-β and (±)-γ-HBCD with 92.6 % bromine-removal was achieved at 60 min in optimal system of anaerobic methanol-water (70:30) mixture with 0.5 % Pd/HR-g-C 3 N 4 , being superior to most studied HBCD catalytic systems. The higher photocatalytic reduction performance is contributed to enhanced photoexcited-carriers separation and more negative conduction band arising from distinctive 1D-cavity of HR-g-C 3 N 4 , and surface-atomically dispersed Pd. A never-reported degradation pathway in which hydrodebromination and addition ring-opening synergistically occur is proposed according to identified products of ten saturated chain alkanes, C 12 H 19 Br 5 and C 12 H 19 Br 7 . Ulteriorly, hydride-transfer resulted in rapid hydrodebromination of HBCD over Pd/HR-g-C 3 N 4 , where H chiefly derives from methanol instead of water although they synergistically promoted e − utilization. This provided a valuable sight into the cost-effective pollution-removal of HBCD.