Synergy of CoN3 and CuN3O2 sites in single atom-decorated biochar for peroxymonosulfate activation: Accelerating the production of SO4•− and •OH

Abstract

The coordination environment of metal affects the catalytic activity significantly, and synergistic interactions between metal sites might play an important role in the peroxymonosulfate (PMS) activation process. Bimetallic doped biochar exhibited greater PMS activation capability than single metal doped biochar. Quenching experiments revealed that cobalt (Co) and copper (Cu) doping could promote the generation of SO4•− and •OH, but was detrimental to the production of 1O2. Density functional theory (DFT) simulations demonstrated that biochar loaded with both CoN3 and CuN3O2 sites had the largest absolute value of Eads, the longest O-O bond length and the maximal electrons transfer, thus facilitating the production of SO4•− and •OH. The CuN3O2 site was excellent for generating 1O2 due to its low reaction energy barrier. In addition, NBC-Cu-Co was an environmentally friendly catalyst in activating PMS to produce low-toxicity intermediates as well as reduce leaching of metal ions.