Insight into the performance and mechanism of peroxymonosulfate activation by B, N co-doped hierarchical porous carbon for phenol degradation

A series of boron and nitrogen co-doped hierarchical porous carbon materials (BNC) were prepared via a facile one-step calcination process, and the catalytic performance of BNC on PMS activation for phenol removal was investigated. BNC-1 exhibited the optimal catalytic performance with a phenol degradation efficiency of 99.6% within 30 min. B, N co-doping strategy improved the specific surface areas (SSA) and total pore volumes (TPV) of carbon catalysts, providing them with abundant active sites, among which graphitic N and BC(3 )were identified as critical catalytic sites for PMS activation. Quenching tests, electron paramagnetic resonance (EPR) and electrochemical experiments demonstrated that singlet oxygen (O-1(2)) was the dominant active species while surface -bound sulfate radical (SO4 center dot-) played an inferior role in the BNC-1/PMS/Phenol system, and the role of hydroxyl radical (center dot OH), superoxide radical (O-2(center dot-)) and surface electron transport cannot be ignored either. The coexistence of radical and non-radical oxidation processes made BNC-1/PMS system have excellent acid-base tolerance (pH=3-11), anti-interference ability and pollutant mineralization performance (68.3% of TOC removal within 30 min). This study presented a high-efficiency and environment-friendly B, N co-doped metal-free catalyst for pollutants degradation via PMS activation and provided an in-depth research for the mechanism of PMS activation by BNC.