Valorization　of　iron-rich　metallurgical　slags　in　the　construction　of　Fenton-like　catalysts　has　an　appealing　potential　from　the　perspective　of　sustainable　development.　For　the　first　time,　copper　smelting　slag　(CSS)　was　utilized　as　the　precursor　to　synthesize　hollow　sea　urchin-like　Fe–Cu　nanoreactors　(Cu1.5Fe1Si)　to　activate　peroxymonosulfate　(PMS)　for　chlortetracycline　hydrochloride　(CTC)　degradation.　The　hyper-channels　and　nano-sized　cavities　were　formed　in　the　catalysts　owing　to　the　induction　and　modification　of　Cu,　not　only　promoting　the　in-situ　growth　of　silicates　and　the　formation　of　cavities　due　to　the　etching　of　SiO2　microspheres,　but　also　resulting　the　generation　of　nanotubes　through　the　distortion　and　rotation　of　the　nanosheets.　It　was　found　that　100　%　CTC　degradation　rate　can　be　achieved　within　10　min　for　Cu1.5Fe1Si,　75　times　higher　than　that　of　Cu0Fe1Si　(0.0024　up　to　0.18　M−1‧min−1).　The　unique　nanoconfined　microenvironment　structure　could　enrich　reactants　in　the　catalyst　cavities,　prolong　the　residence　time　of　molecules,　and　increase　the　utilization　efficiency　of　active　species.　Density　functional　theory　(DFT)　calculations　show　that　Cu1.5Fe1Si　has　strong　adsorption　energy　and　excellent　electron　transport　capacity　for　PMS,　and　Fe-Fe　sites　are　mainly　responsible　for　the　activation　of　PMS,　while　Cu　assists　in　accelerating　the　Fe(II)/Fe(Ⅲ)　cycle　and　promotes　the　catalytic　efficiency.　The　excellent　mineralization　rate　(83.32　%　within　10　min)　and　efficient　treatment　of　CTC　in　consecutive　trials　corroborated　the　high　activity　and　stability　of　the　Cu1.5Fe1Si.　This　work　provides　a　new　idea　for　the　rational　design　of　solid　waste-based　eco-friendly　functional　materials,　aiming　at　consolidating　their　practical　application　in　advanced　wastewater　treatment.　©　2024　Elsevier　Inc.