Surface Al and Co coordination for peroxymonosulfate activation: identification and mechanism

• Main Authors: Zhu, Min-Ping, Yang, Jia-Cheng E., Guan, Daqin, Yuan, Baoling, Duan, Xiaoguang, Sun, Darren Delai, Sun, Chenghua, Wang, Shaobin, Fu, Ming-Lai
• Other Authors: School of Civil and Environmental Engineering
• Format: Article
• Language: English
• Published: 2023
• Subjects: Engineering::Environmental engineering; Metal-Support Interaction; Support-Surface Reconstruction
• Online Access: https://hdl.handle.net/10356/172878
• Institution: Nanyang Technological University

Deciphering the metal-support interaction-oriented catalysis on millimeter-scaled catalysts is highly desirable yet remains scarce in Fenton-like catalysis. Herein, we fine-tune the support-surface reconstruction of Co2AlO4 on γ-Al2O3 millispheres and reveal the origins of its activity in peroxymonosulfate activation by nuclear magnetic resonance and X-ray photoelectron/adsorption spectroscopy. Calcination of γ-Al2O3 supports rearranged their surface octahedral, tetrahedral and pentacoordinate Al3+. The reconstructed tetrahedral and pentacoordinate Al3+ as binding sites regulated the formation of Co2AlO4 with coordinated Co3+/Co2+ redox centers via strong metal-support interactions. The activities of tailored Co2AlO4 @Al2O3 millispheres in activating peroxymonosulfate follow different binomial models, highly relying on their Co3+/Co2+ ratio, contents of lattice O and pentacoordinate Al3+. The Co-O-Al bonds endow the millimeter-scaled Co2AlO4 @Al2O3 with robust catalytic activity, stability and reusability. The exposed Co2AlO4 (200) surface is responsible for the decomposition of PMS into produce SO4•[sbnd] and 1O2 as the dominant oxidants for water detoxification.