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Acid Etching-Induced In Situ Growth of λ-MnO2 over CoMn Spinel for Low-Temperature Volatile Organic Compound Oxidation
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2022-06-16 , DOI: 10.1021/acs.est.2c02483 Cangpeng Shan 1 , Yan Zhang 1 , Qian Zhao 2 , Kaixuan Fu 1 , Yanfei Zheng 1 , Rui Han 1 , Caixia Liu 1 , Na Ji 1 , Weichao Wang 3 , Qingling Liu 1
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2022-06-16 , DOI: 10.1021/acs.est.2c02483 Cangpeng Shan 1 , Yan Zhang 1 , Qian Zhao 2 , Kaixuan Fu 1 , Yanfei Zheng 1 , Rui Han 1 , Caixia Liu 1 , Na Ji 1 , Weichao Wang 3 , Qingling Liu 1
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Surface lattice oxygen is crucial to the degradation of volatile organic compounds (VOCs) over transition metal oxides according to the Mars–van Krevelen mechanism. Herein, λ-MnO2 in situ grown on the surface of CoMn spinel was prepared by acid etching of corresponding spinel catalysts (CoMn-Hx-Ty) for VOC oxidation. Experimental and relevant theoretical exploration revealed that acid etching on the CoMn spinel surface could decrease the electron cloud density around the O atom and weaken the adjacent Mn–O bond due to the fracture of the surface Co–O bond, facilitating electron transfer and subsequently the activation of surface lattice oxygen. The obtained CoMn-H1-T1 exhibited an excellent catalytic performance with a 90% acetone conversion at 149 °C, which is 42 °C lower than that of CoMn spinel. Furthermore, the partially maintained spinel structure led to better stability than pure λ-MnO2. In situ diffuse reflectance infrared Fourier transform spectroscopy confirmed a possible degradation pathway where adsorptive acetone converted into formate and acetate species and into CO2, in which the consumption of acetate was identified as the rate-limiting step. This strategy can improve the catalytic performance of metal oxides by activating surface lattice oxygen, to broaden their application in VOC oxidation.
中文翻译：
酸蚀诱导 λ-MnO2 在 CoMn 尖晶石上原位生长用于低温挥发性有机化合物氧化
根据 Mars-van Krevelen 机制，表面晶格氧对于过渡金属氧化物上挥发性有机化合物 (VOC) 的降解至关重要。在此，通过酸蚀刻相应的尖晶石催化剂（CoMn- H x -T y) 用于 VOC 氧化。实验和相关理论探索表明，酸蚀刻 CoMn 尖晶石表面可以降低 O 原子周围的电子云密度，并由于表面 Co-O 键的断裂而削弱相邻的 Mn-O 键，从而促进电子转移，从而促进电子转移。表面晶格氧的活化。得到的 CoMn-H1-T1 表现出优异的催化性能，在 149 ℃时丙酮转化率为 90%，比 CoMn 尖晶石低 42 ℃。此外，部分保持的尖晶石结构比纯λ-MnO 2具有更好的稳定性。原位漫反射红外傅里叶变换光谱证实了一种可能的降解途径，其中吸附性丙酮转化为甲酸盐和乙酸盐物质并转化为 CO 2，其中乙酸盐的消耗被确定为限速步骤。该策略可以通过活化表面晶格氧来提高金属氧化物的催化性能，从而拓宽其在VOC氧化中的应用。
更新日期：2022-06-16
中文翻译：
酸蚀诱导 λ-MnO2 在 CoMn 尖晶石上原位生长用于低温挥发性有机化合物氧化
根据 Mars-van Krevelen 机制，表面晶格氧对于过渡金属氧化物上挥发性有机化合物 (VOC) 的降解至关重要。在此，通过酸蚀刻相应的尖晶石催化剂（CoMn- H x -T y) 用于 VOC 氧化。实验和相关理论探索表明，酸蚀刻 CoMn 尖晶石表面可以降低 O 原子周围的电子云密度，并由于表面 Co-O 键的断裂而削弱相邻的 Mn-O 键，从而促进电子转移，从而促进电子转移。表面晶格氧的活化。得到的 CoMn-H1-T1 表现出优异的催化性能，在 149 ℃时丙酮转化率为 90%，比 CoMn 尖晶石低 42 ℃。此外，部分保持的尖晶石结构比纯λ-MnO 2具有更好的稳定性。原位漫反射红外傅里叶变换光谱证实了一种可能的降解途径，其中吸附性丙酮转化为甲酸盐和乙酸盐物质并转化为 CO 2，其中乙酸盐的消耗被确定为限速步骤。该策略可以通过活化表面晶格氧来提高金属氧化物的催化性能，从而拓宽其在VOC氧化中的应用。
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