Synergistic mechanism of Ni/O dual-doped g-C3N4 activated peroxymonosulfate for Acid Orange 7 degradation: A combined experimental and DFT study

Acid Orange 7 (AO7) is a recalcitrant contaminant exhibiting persistent resistance to degradation in aquatic environments. Materials based on graphitic carbon nitride ( ) demonstrate significant potential in removing pollutants like AO7 through synergistic interactions with oxidants, utilizing their exceptional catalytic properties and high surface area for adsorption. However, their effectiveness is limited by a relatively large band gap, which hinders their catalytic performance. This study reveals that Ni/O dual-doped (NiOCN) effectively optimizes the structure and catalytic performance of . Experimental results indicate that the NiOCN/peroxymonosulfate (PMS) system exhibits optimal AO7 degradation performance, achieving 92.3% degradation within 10 min while maintaining 80% efficiency in simulated aqueous matrices. Quenching experiments further identified superoxide anion radicals ( ⋅ O 2 − ) as the predominant reactive species governing AO7 degradation. Using density functional theory (DFT) calculations, we confirmed that Ni/O dual-doping narrows the band gap and boosts catalytic activity. Our findings mechanistically demonstrate that Ni/O dual-doping augments PMS activation performance by introducing impurity energy levels, increasing adsorption sites, and accelerating electron migration kinetics.