Li Meijun, Tian Mengkun, Chen Hao, Mahurin Shannon Mark, Wu Zili, Dai Sheng
Chemical Sciences Division, Oak Ridge National Laboratory 1 Bethel Valley Road Oak Ridge TN 37831 USA
Department of Material Science and Engineer, University of Tennessee 1420 Circle Drive Knoxville TN 38996 USA.
RSC Adv. 2020 Aug 4;10(48):28731-28740. doi: 10.1039/d0ra02736g. eCollection 2020 Aug 3.
A series of metal silicates, NaMSiOx (M = Cu, Mn and Ni), were prepared by doping of metals into mesoporous SBA-15 under a hydrothermal process, displaying a continuous framework of SiO structure with a narrow pore size distribution. These metal silicate materials were tested for CO adsorption behavior in the absence and presence of water. The results exhibited that the effect of HO on the CO capture capability of metal silicates depends on the types of metal inserted into SBA-15. Compared to the dry condition, HO addition enhances CO uptake dramatically for NaCuSiOx by 25%, and slightly for NaNiSiOx (∼10%), whereas little effect is shown on NaMnSiOx. The metal silicate materials are stable after adsorption of CO under wet conditions, which is benefited from their synthesis method, hydrothermal conditions. The improvement of CO uptake on metal silicates by HO is attributed to the competitive and synergistic adsorption mechanism on the basis of IR investigations, where initially adsorbed HO acts as a promoter for further CO capture through a hydration reaction, , formation of bicarbonate and carbonates on the surface of the samples. These observations provide new possibilities for the design and synthesis of porous metal silicate materials for CO capture under practical conditions where moisture is present.
通过水热法将金属掺杂到介孔SBA - 15中制备了一系列金属硅酸盐NaMSiOx（M = Cu、Mn和Ni），其呈现出具有窄孔径分布的连续SiO结构骨架。对这些金属硅酸盐材料在无水和有水条件下的CO吸附行为进行了测试。结果表明，H₂O对金属硅酸盐CO捕获能力的影响取决于插入SBA - 15中的金属类型。与干燥条件相比，添加H₂O后，NaCuSiOx的CO吸收量显著提高25%，NaNiSiOx略有提高（约10%），而对NaMnSiOx几乎没有影响。金属硅酸盐材料在潮湿条件下吸附CO后是稳定的，这得益于其合成方法即水热条件。基于红外研究，H₂O对金属硅酸盐上CO吸收的改善归因于竞争和协同吸附机制，其中最初吸附的H₂O通过水合反应、在样品表面形成碳酸氢盐和碳酸盐，作为进一步捕获CO的促进剂。这些观察结果为在存在水分的实际条件下设计和合成用于捕获CO的多孔金属硅酸盐材料提供了新的可能性。
