Confinement of CoP Nanoparticles in Nitrogen-Doped Yolk-Shell Porous Carbon Polyhedron for Ultrafast Catalytic Oxidation

Catalytic oxidation of toxic organic pollutants in water urgently requires improved efficiency for practical application. Here a wrapping-pyrolysis strategy is exploited to convert CoP nanowires-threaded ZIF-8 into CoP nanoparticles-confined nitrogen-doped yolk-shell porous carbon polyhedra, featuring high-density active sites, and high adsorbability, dispersibility and conductivity (4-High). The nanoreactor efficiently activates peroxymonosulfate for bisphenol A (BPA) degradation over a wide pH range and in saline solutions. The apparent kinetic rate constant (18.96 min(-1)) is the highest reported to date and exceeds those of reported catalysts by 1-2 orders of magnitude. Experimental and theoretical evidence reveals that the catalysis occurs at the Co4P4@graphitic nitrogen-doped graphene site to produce surface-bound SO(4)(center dot-)and induce direct electron abstraction for BPA degradation. The high catalytic activity is attributed to the unique yolk-shell structure which concentrates catalytic and adsorptive sites within a confined space, as well as to the porous carbon polyhedron with high dispersibility and conductivity for fast mass and electron transport. Moreover, a fluidized-bed catalytic unit is constructed and enables continuous zero discharge of BPA and easy nanocatalyst recycling. This work will guide 4-High catalyst design to improve future deep water purification technology.