Sci. Adv. 过渡金属盐催化无机小分子分解多功效碳质料

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     碳纳米质料因具有高的导电性、优秀的凯发波动性、共同的微观布局等物感性质,在情况、动力、催化、电子器件和聚合物等范畴有着普遍的使用。分外是拥有高的比外表积、多孔布局、抱负的杂原子掺杂等特性的碳纳米质料,其使用将愈加具有竞争力。传统碳化低蒸气压的天然产品(如纤维素和淀粉)很难控制所得碳质料的微观布局和杂原子掺杂。与此同时,利用分解聚合物为先驱物制备碳纳米质料历程庞大迟缓,且不易范围化消费。因而,开辟复杂、便宜、可控的办法宏量制备碳纳米质料仍然面对宏大应战。

 

    中国迷信技能大学俞书宏传授和梁海伟传授研讨团队开展了一种过渡金属盐催化无机小分子碳化的分解新途径,完成了在分子层面可控的宏量分解多孔掺杂碳纳米质料。该研讨效果宣布《迷信·停顿》上: Zhen-Yu Wu et al., Transition metal-assisted carbonization of small organic molecules toward functional carbon materials, Sci. Adv.,  2018, 4, eaat0788,论文第一作者是博士后吴振禹和硕士生许实龙。

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 (A)过渡金属帮助碳化无机分子制备碳纳米质料的表示图;(B)该办法所利用的无机小分子先驱物的布局

 

    无机小分子因其普遍存在、品种多样、元素丰厚,是一种抱负的制备碳纳米质料的先驱体。但在低温下无机小分子高的挥发性使得其作为质料制备碳纳米质料必需利用庞大办法和设置装备摆设,如凯发气相堆积和高压密闭分解。迄今为止,仍缺乏复杂无效的办法碳化无机小分子来制备碳纳米质料。针对上述应战,研讨职员提出了一种过渡金属帮助无机分子碳化的办法,经过利用过渡金属盐帮助热解无机小分子(见上图A)来制备碳纳米质料。在低温热解的历程中,过渡金属盐不但可以进步小分子的热波动,还能催化其聚合优先构成响应的聚合物两头体,制止无机小分子在低温热解中挥发从而终极构成碳纳米质料。他们发明至多15种无机小分子(见上图B)和9种过渡金属盐可以作为碳先驱物和催化剂来制备响应的碳基纳米质料,同时多种硬模板可以用在该办法中来进步所得质料的比外表积和多孔性。研讨后果标明,该办法是一种普适、复杂、高效的碳纳米质料的分解办法。

 

    运用这种办法制备的碳质料具有三种微观布局:竹节状的多壁纳米管、微米标准的片和无规矩的颗粒。这些碳纳米质料比外表积和孔体积最高可达1202 m2g-1和2.16 cm3g-1,并具有丰厚的杂原子,如硫元素的含量最高可达13.35%,氮元素的含量可达6.44%,还具有很高的石墨化水平。该法制备的多孔碳纳米质料在选择性乙苯氧化、硝基苯氢化、析氢反响、氧复原反响中均体现出优秀的催化功能,是一类抱负的多相催化剂和电催剂。

 

    这项研讨为高效制备碳纳米质料提供了一种普适的分解道路,对以后开展分解具有抱负布局和身分的碳纳米质料具有引导意义。



Fig. 1. Preparation of carbon materials (CMs). (A) Schematic illustration of the preparation process of CMs. (B) Structures of the investigated small organic molecules (SOMs) for the CM preparation.

Fig. 2. TGA analyses. (A) TGA curves of different SOMs (TMS-free) in N2 atmosphere. (B) TGA curves of different SOMs with Co(NO3)2 in N2 atmosphere. (C) TGA curves of oPD with different TMSs in N2 atmosphere. (D) TGA curves of oPD with different Co(NO3)2 contents in N2 atmosphere.

Fig.3. Microscopic characterization of CMs.(A to F) SEM and TEM images of CM-DCD/Co (A and B), CM-oPD/Co (C and D), and CM-BPy/Co (E and F). (G and H) HRTEM images of CM-DCD/Co (G) and CM-oPD/Co (H).

Fig. 4. Textural properties and chemical compositions of CMs. (A) Nitrogen adsorption/desorption isotherms of selected CMs. STP, standard temperature and pressure. (B) PSD of CM-DBrBPy/Co and CM-DBrBPy/Co/SiO2. (C) XRD patterns of CMs. a.u., arbitrary units. (D) Raman spectra of CMs. (E) XPS survey spectra of CM-DCD/Co and CM-BTH/Co. (F) High-resolution XPS spectra of the deconvoluted N 1s peak and Co 2p peak for CM-DCD/Co.

Fig. 5. Catalytic performance of CMs for selective oxidization of ethylbenzene and hydrogenation of nitrobenzene. (A) Reaction equation of selective oxidization of ethylbenzene. TBHP, tert-butyl hydroperoxide. (B and C) Activity (B) and stability (C) tests of CM catalysts for ethylbenzene oxidization.(D) Reaction equation of hydrogenation of nitrobenzene. (E and F) Activity (E) and stability (F) tests of CM catalysts for nitrobenzene hydrogenation.

Fig. 6. Electrocatalytic performance of CMs for HER. (A and B) Polarization curves of CM-DBrPhen/Co/SiO2 and commercial Pt/C catalyst in 0.5 M H2SO4 (A) and 1 M KOH (B). (C) Chronopotentiometry tests of CM-DBrPhen/Co/SiO2 at 10 mA cm-2 in 0.5 M H2SO4 and 1 M KOH, respectively.



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