TY - JOUR
T1 - Nitrogen-modified manganese oxide activated peroxymonosulfate for pollutant degradation
T2 - Primary role of interstitial N sites
AU - Su, Yinmei
AU - Sun, Wei
AU - Yuan, Lizhu
AU - Yang, Wenchao
AU - Zhang, Qichun
AU - Wong, Jonathan W.C.
N1 - This study was financially supported by the GuangDong Basic and Applied Basic Research Foundation (No. 2019A1515110649; 2020A1515110271; 2019A1515110244); the Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion (MATEC2022KF011).
Publisher Copyright:
© 2024 Elsevier Ltd.
PY - 2024/7
Y1 - 2024/7
N2 - Nitrogen anion doping has been considered as an effective strategy to modulate the electronic structure of transition metal oxides and improve their catalysis. However, the roles of interstitial and substitutional N sites in PMS activation remained be unclear. To address this issue, N-doped MnOx with different N configurations were synthesized through calcining their precursors at different temperatures with urea. The incorporation of N atom into manganese oxide lattice remarkably enhanced the catalytic activity. Correspondingly, N-Mn-300/PMS system obtained a removal rate of 99.8% and mineralization rate of 87.8%, whose kobs (0.1067 min−1) was 16.1- and 12.4-folds higher than that of raw ɛ-MnO2 (0.0066 min−1) and Mn-300 (0.0086 min−1). Such promotion was mainly attributed to the decreased electron cloud density of Mn neighboring interstitial N atom, which provided a driving force to induce transfer electron from PMS to Mn, subsequently causing PMS oxidation into 1O2. By contrast, the substitutional N increased the electron density of Mn and exhibited a minor promotion effect in the enhanced catalysis. A possible catalytic mechanism of MnII OH/SO4 → Mn (III) ← O12 Mn (IV) was proposed. Notably, it was newly discovered that this K2Cr2O7-induced inhibition was attributed to the catalytic site consumption of N-Mn-300 by K2Cr2O7, rather than K2Cr2O7-quenching free electron. This work highlights the primary role of interstitial N site in regulating the electronic structure of manganese oxide to strengthen peroxymonosulfate activation.
AB - Nitrogen anion doping has been considered as an effective strategy to modulate the electronic structure of transition metal oxides and improve their catalysis. However, the roles of interstitial and substitutional N sites in PMS activation remained be unclear. To address this issue, N-doped MnOx with different N configurations were synthesized through calcining their precursors at different temperatures with urea. The incorporation of N atom into manganese oxide lattice remarkably enhanced the catalytic activity. Correspondingly, N-Mn-300/PMS system obtained a removal rate of 99.8% and mineralization rate of 87.8%, whose kobs (0.1067 min−1) was 16.1- and 12.4-folds higher than that of raw ɛ-MnO2 (0.0066 min−1) and Mn-300 (0.0086 min−1). Such promotion was mainly attributed to the decreased electron cloud density of Mn neighboring interstitial N atom, which provided a driving force to induce transfer electron from PMS to Mn, subsequently causing PMS oxidation into 1O2. By contrast, the substitutional N increased the electron density of Mn and exhibited a minor promotion effect in the enhanced catalysis. A possible catalytic mechanism of MnII OH/SO4 → Mn (III) ← O12 Mn (IV) was proposed. Notably, it was newly discovered that this K2Cr2O7-induced inhibition was attributed to the catalytic site consumption of N-Mn-300 by K2Cr2O7, rather than K2Cr2O7-quenching free electron. This work highlights the primary role of interstitial N site in regulating the electronic structure of manganese oxide to strengthen peroxymonosulfate activation.
KW - Advanced oxidation processes
KW - Interstitial N site
KW - Nitrogen anion doping
KW - Peroxymonosulfate
KW - Singlet oxygen
UR - http://www.scopus.com/inward/record.url?scp=85195274351&partnerID=8YFLogxK
U2 - 10.1016/j.jwpe.2024.105574
DO - 10.1016/j.jwpe.2024.105574
M3 - Journal article
AN - SCOPUS:85195274351
SN - 2214-7144
VL - 64
JO - Journal of Water Process Engineering
JF - Journal of Water Process Engineering
M1 - 105574
ER -