The photocatalyst with a strong internal electric field grown in situ on the surface of copper foam collaborates with peroxymonosulfate to enhance directional charge transfer and achieve ultra-fast Mn+/M(n+1)+ cycling

•Vertical nanosheet heterojunction was grown in-situ on the surface of copper foam.•DFT and KPFM demonstrate a strong built-in electric field inside a heterojunction.•Built-in electric field promotes directional movement of e− and activates PMS.•The system achieves efficient Mn+/M(n+1)+ cycling and low metal leaching rates.•The CF@CCS@CO-3/7/Vis/PMS system degraded ciprofloxacin by nearly 100 % in 60 min.