Potassium and Zeolitic Structure Modified Ultra-microporous Adsorbent Materials from a Renewable Feedstock with Favorable Surface Chemistry for CO2 Capture.
Potassium and Zeolitic Structure Modified Ultra-microporous Adsorbent Materials from a Renewable Feedstock with Favorable Surface Chemistry for CO2 Capture.
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DOI：
10.1021/acsami.7b06665
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发表时间：
2017-08
影响因子：
9.5
通讯作者：
Xin Liu;Yuan Sun;Jingjing Liu;Cheng-gong Sun;Hao Liu;Qianhui Xue;Emily F. Smith;C. Snape
中科院分区：
文献类型：
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作者：
Xin Liu;Yuan Sun;Jingjing Liu;Cheng-gong Sun;Hao Liu;Qianhui Xue;Emily F. Smith;C. Snape
以农业废弃物稻壳（RH）为原料，采用一种简单的方法，将碳化、活化和钾插层有效地结合到一步反应过程中，合成了具有高CO2捕集能力的多级微孔生物炭。纹理表征表明，合成的生物碳表现出非常高的超微孔占总孔隙率高达95%，主要是由于RH分子框架结构内的天然存在的硅化合物。性能最佳的RH碳具有高达1035 m2/g的适度表面积和0.43 cm 3/g的总孔体积，在25 °C和0.15 bar的CO2分压下显示出2.0 mmol/g的异常高且完全可逆的CO2吸收能力，这代表了对于通常使用成本高昂的前体材料以繁琐的方法制备的碳和MOF材料报道的最高吸收率之一。已经发现，高达50%的总CO2吸收归因于RH碳的独特表面化学，其似乎由由于极高水平的超微孔性和碳基质内结合的沸石结构的存在而增强的骨架外钾阳离子的形成所主导。通过EDX元素图谱、XPS和吸附热测量的表征证实了一系列沸石结构的存在，这基本上将RH碳转化为一种对CO2具有强表面亲和力的沸石-碳纳米复合材料。
Novel hierarchically structured microporous biocarbons with exceptionally high capacities for CO2 capture have been synthesized from the abundant agricultural waste of rice husk (RH), using a facile methodology that effectively integrated carbonization, activation, and potassium intercalation into a one-step process. Textural characterization demonstrates that the synthesized biocarbons exhibit exceedingly high ultra-microporosity accounting for up to 95% of total porosity mainly as a result of the naturally occurring silicon compounds within the RH molecular framework structures. With a modest surface area of up to 1035 m2/g and a total pore volume of 0.43 cm3/g, the best performing RH carbon has shown exceptionally high and fully reversible CO2 uptake capacity of 2.0 mmol/g at 25 °C and a CO2 partial pressure of 0.15 bar, which represents one of the highest uptakes ever reported for both carbon and MOF materials usually prepared from using cost-prohibitive precursor materials with cumbersome methodologies. It has been found that up to 50% of the total CO2 uptake is attributable to the unique surface chemistry of the RH carbons, which appears to be dominated by the enhanced formation of extra-framework potassium cations owing to the exceedingly high levels of ultra-microporosity and the presence of zeolitic structures incorporated within the carbon matrices. Characterizations by EDX element mapping, XPS, and heat of adsorption measurements confirm the existence of a range of zeolitic structures, which essentially transforms the RH carbons into a kind of zeolite-carbon nanocomposite material with strong surface affinity for CO2.