Oxygen vacancies and N-doped carbon layer synergistically enhance singlet oxygen generation over BiOCl for efficient pollutant degradation
Chenyu Zhang, Zeyan Zhou, Chenhong Wu, Hao Zeng, Qiongfang Wan, Hui Li, Hanbo Yu, Haoliang Pang, Jinhui Huang, Xingzhong Yuan
Abstract
Abstract Photocatalytic activation of molecular oxygen (O 2 ) into reactive oxygen species (ROS) is pivotal for water purification, yet achieving selective ROS generation remains challenging. In this work, we successfully fabricated N-doped carbon-coated BiOCl (BNC) photocatalysts featuring abundant surface oxygen vacancies (OVs), a unique structure that synergistically enhances excitonic effects and promotes singlet oxygen ( 1 O 2 ) generation. The N-doped carbon layer synergistically with OVs boosts 1 O 2 generation by facilitating spin–orbit coupling, reducing the singlet–triplet energy gap by 36% to promote intersystem crossing, and enhancing O 2 chemisorption/activation by O–O bond lengthening to 1.52 Å, resulting in a tenfold 1 O 2 yield increase over pristine BiOCl. Optimized BNC10 sample completely degraded ciprofloxacin in 60 min under visible-light irradiation, with 6.9-fold higher rate constant, showed > 87% removal in real waters. Toxicity assessments confirmed the low ecological risk of degradation intermediates, while mineralization experiments demonstrated 80% total organic carbon (TOC) removal. This work provides a novel strategy for excitonic regulation in 2D semiconductors, advancing the design of selective photocatalysts for sustainable environmental remediation. Graphical Abstract Boosted energy-transfer-mediated molecular oxygen activation by coating N-doped carbon layer endows BiOCl with high yield of 1 O 2 toward efficient degradation of various pollutants.