Construction of AgCl/PbFe12O19 heterojunction with enhanced photocatalytic activity for pollutant degradation and mechanism insight

AgCl/PbFeO composite photocatalysts with varying AgCl contents were successfully synthesized using the polyacrylamide gel method combined with photoreduction method. Photocatalytic experiments demonstrated selective degradation of doxycycline hydrochloride (DC), tetracycline hydrochloride (TC), chlortetracycline hydrochloride (CTC), Rhodamine B (RhB), and Congo red (CR), particularly targeting azo (–N=N–) double bonds and sulfonate (–SO₃Na) groups. Under optimal condition, 15% mass ratio of AgCl, 20 mg/L initial concentration of CR, pH 7, and 120 min of photocatalytic reaction, the degradation efficiency of CR dye reached 86%. Free radical scavenging experiments revealed that holes, hydroxyl radicals, and superoxide radicals were the primary active species responsible for degradation. Based on experimental results and band theory analysis, it was determined that AgCl and PbFeO form a type II heterojunction, which facilitates charge transfer and separation, thereby enhancing photocatalytic activity. This composite photocatalyst effectively targets specific functional groups, and its mechanism for promoting dye degradation holds promise for the development of advanced photocatalysts for environmental purification.