Wu Jianzhong, Zhang Jia, Cao Zhenbang, Liu Qizhen, Wei Feng, Zhou Jizhi, Wang Da, Shi Siqi, Qian Guangren
School of Chemical Engineering and Australian Centre for Nanomedicine (ACN) , University of New South Wales , Sydney , New South Wales 2052 , Australia.
ACS Appl Mater Interfaces. 2019 May 8;11(18):16538-16545. doi: 10.1021/acsami.9b01432. Epub 2019 Apr 23.
An economic and facile method was urgently required for the degradation of SF to replace the high-energy excitation treatment. Both theoretical calculations and experimental observations were conducted to reveal the synergy of Cr/Fe/Si composites on a new technique of SF degradation through reacting silicon dioxide. Density functional theory (DFT) calculations show that strong adsorption of SF on CrO, and then the fast F/O exchange between CrF and FeO (energy barrier was 1.45 eV) as well as FeF and SiO (energy barrier was 1.69 eV) enhanced mediated efficiency from SF to SiF. The fluorine (F) migration between solid interfaces in CrO&FeO@SBA15 was responsible for efficient SF removal. The F migration route was composed of SF to CrF, CrF to FeF, and FeF to SiF with the lowest thermodynamic driving. Enhanced specific accumulative converted amount (SACA) of SF on CrO&FeO@SBA15 was achieved and the highest SACA was 13.98 mmol/g within 7 h, significantly higher than that on FeO@SBA15 (5.74 mmol/g) and CrO@SBA15 (2.71 mmol/g). Moreover, X-ray diffractometry and X-ray photoelectron spectroscopy were performed to support DFT calculations, including ion intensities detected using mass spectroscopy and composition analysis of the mediator during the reaction. Therefore, our work put forward a novel approach for economic and efficient SF decomposition through reacting with silicon dioxide under the mediation of CrO&FeO. This method was also potentially used in effective degradation of refractory non-metal halides.
