Fabrication of vessel–like biochar–based heterojunction photocatalyst Bi2S3/BiOBr/BC for diclofenac removal under visible LED light irradiation: Mechanistic investigation and intermediates analysis

•Bi2S3/BiOBr/BC was fabricated via a facile one–pot solvothermal method firstly.•High charge separation and electron transfer of biochar promoted DCF removal process.•Lower EEO value meant less energy consumption under visible LED light irradiation.•O2– and h+ dominated the photodegradation reaction to mineralize DCF molecules.•11 main products of DCF and 4 degradation pathways were determined by HRMS analysis.