Preforming abundant surface cobalt hydroxyl groups on low crystalline flowerlike Co3(Si2O5)2(OH)2 for enhancing catalytic degradation performances with a critical nonradical reaction

• Published in: Applied catalysis. B, Environmental Vol. 261; p. 118238
• Main Authors: Zhu, Zhong-Shuai, Yu, Xiao-Jie, Qu, Jin, Jing, Ya-Qiong, Abdelkrim, Yasmine, Yu, Zhong-Zhen
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-02-2020; Elsevier BV
• Subjects: Adaptability; Advanced oxidation process; Carbon dioxide; Catalysts; Cobalt; Cobalt silicate hydroxides; Crystal structure; Crystallinity; Hydroxyl groups; Peroxymonosulfate; Pollutants; Preforming; Singlet oxygen; Surface cobalt hydroxyl groups; Singlet oxygen; Peroxymonosulfate; Cobalt silicate hydroxides; Surface cobalt hydroxyl groups; Advanced oxidation process
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2019.118238

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•Low crystalline flowerlike Co3(Si2O5)2(OH)2 is generated for efficient degradation.•A large amounts of highly active CoOH+ are accurately preformed on CoSiOx surface.•The low crystallinity of CoSiOx leads to the formation of active singlet oxygen.•NH4Cl regulates nucleation and growth rates of CoSiOx in the hydrothermal process.
Low crystalline flowerlike cobalt silicate hydroxide (Co3(Si2O5)2(OH)2, CoSiOx) is synthesized by a one-pot hydrothermal approach. Abundant highly active CoOH+ is preformed on the surface of CoSiOx, while the low crystallinity of CoSiOx leads to the formation of active 1O2 caused by the generation of oxygen vacancy in the valence change cycle between Co2+ and Co3+. The optimal CoSiOx with a high specific surface area of 665.2 m2 g−1 could expose surface CoOH+, thus rapidly activate peroxymonosulfate (PMS) and accelerate catalytic efficiencies. As a result, at least 11 kinds of organic pollutants could be degraded with 33–242% higher efficiencies than reported. In addition to the common SO4- and OH, large amounts of active 1O2 endow the CoSiOx/PMS system with superb catalytic performances in diverse conditions, suggesting the excellent adaptability for practical usage. This work provides a new protocol to advance the PMS activation process for high-performance cobalt based heterogeneous catalysts.