Li Ping, Zhan Shujuan, Yao Lan, Xiong Ya, Tian Shuanghong
School of Environmental Science & Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation, China.
School of Environmental Science & Engineering, Sun Yat-sen University, Guangzhou 510275, China.
J Hazard Mater. 2022 Sep 5;437:129235. doi: 10.1016/j.jhazmat.2022.129235. Epub 2022 May 26.
Herein we reported the first example of preparing α-MnO by selective acid etching from Mn-containing spinel. The defects, facet, and surface area of α-MnO were cooperatively engineered by an all-in-one acid etching method to enhance the defect accessibility to the reactants. The obtained highly porous α-MnO nanorods have rich defects of Mn (24.9%) and oxygen vacancies (31.4%), mainly active crystal facets of (110), and an ultrahigh surface area of 271.1 m/g. With α-MnO nanorods as the catalysts, more than 90.9% of 4-chlorophenol can be degraded within 12 min by catalytic ozonation in a wide work pH of 4.5-10.5. The experiments and DFT theory calculations reveal that α-MnO with (110) facet promotes the adsorption and activation of ozone directly over the defects or indirectly over HO adsorbed on the defects. Thus, more reactive oxygen species (e.g., •OH, •O, O, surface *O) are generated and get involved in pollutant degradation. This work provides a facile method to maximize the defect accessibility, and a deeper mechanistic study to understand the roles of the defects.
在此，我们报道了首例通过对含锰尖晶石进行选择性酸蚀刻来制备α - 二氧化锰的实例。通过一体化酸蚀刻方法协同调控α - 二氧化锰的缺陷、晶面和表面积，以提高反应物对缺陷的可达性。所制备的高度多孔α - 二氧化锰纳米棒具有丰富的锰缺陷（24.9%）和氧空位（31.4%），主要活性晶面为（110），比表面积高达271.1 m²/g。以α - 二氧化锰纳米棒为催化剂，在4.5 - 10.5的宽工作pH范围内，通过催化臭氧化反应，12分钟内可降解超过90.9%的4 - 氯苯酚。实验和密度泛函理论计算表明，具有（110）晶面的α - 二氧化锰可直接通过缺陷促进臭氧的吸附和活化，或间接通过吸附在缺陷上的羟基促进臭氧的吸附和活化。因此，会产生更多的活性氧物种（如•OH、•O、O、表面*O）并参与污染物降解。这项工作提供了一种使缺陷可达性最大化的简便方法，以及一项更深入的机理研究，以理解缺陷的作用。
