The pyrolytic reforming of toluene to hydrogen and CNTs over the commercial and self-prepared Al2O3 loaded with Fe through the impregnation method is investigated in a fixed bed reactor under the temperature from 600 °C to 800 °C. The physicochemical properties of Fe–Al2O3 catalysts and Al2O3 supports were characterized by XPS, H2-TPR, HRTEM and H2-pulse chemisorption. The reforming process over the catalyst of Fe loaded on self-prepared Al2O3 gives the excellent H2 yield of 27.8 mmol/(g-Fe) and graphite yield of 82.6 wt%, which is much higher than those from that over the catalyst of Fe loaded on the commercial Al2O3. It is evidenced by H2-pulse chemisorption that 5.1 % of Fe0+ dispersion over the commercial Al2O3 with mainly-exposed (110) facet while 11.2 % of Fe0+ dispersion over self-prepared Al2O3 with mainly-exposed (111) facet were obtained. The adsorption energy of iron cluster (Fe4) with Al2O3 (111) facet was estimated to be −14.5 eV through the DFT simulation, which is notably higher than that of iron cluster (Fe4) with Al2O3 (110) facet as −9.1 eV. With regard to the MD simulation along with XRD analysis of the Fe3C crystallite, Fe0+ particles can be prominently molten at the high Fe0+ dispersion over Al2O3 facet, promoting the carbon solubility for the assembly of multi-wall CNTs without the deposition of unwanted amorphous carbon.

中文翻译：

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γ-Al2O3 对甲苯催化重整共产氢气和 CNT 的 Fe–Al2O3 催化性能的晶体面效应


在 600 °C 至 800 °C 的温度下，在固定床反应器中研究了通过浸渍法将甲苯通过浸渍法在商业和自行制备的 Al2O3 上热解重制成氢和 CNT。 通过 XPS、H2-TPR、HRTEM 和 H2 脉冲化学吸附对 Fe–Al2O3 催化剂和 Al2O3 载体的物理化学性质进行了表征。在自制备的 Al2O3 上负载 Fe 的催化剂上进行重整过程，获得了 27.8 mmol/（g-Fe） 的优异 H2 产率和 82.6 wt% 的石墨产率，远高于负载在商业 Al2O3 上的 Fe 催化剂上的重整过程。H2 脉冲化学吸附证明，在主要暴露 （110） 刻面上获得了 5.1% 的 Fe0+ 分散体，而在主要暴露 （111） 刻面上的自制备 Al2O3 上获得了 11.2% 的 Fe0+ 分散体。通过 DFT 模拟估计铁团团 （Fe4） 与 Al2O3 （111） 刻面的吸附能为 -14.5 eV，明显高于铁团簇 （Fe4） 与 Al2O3 （110） 刻面的 -9.1 eV。关于 Fe3C 微晶的 MD 模拟和 XRD 分析，Fe0+ 颗粒可以在 Al2O3 面上的高 Fe0+ 分散处显着熔化，从而提高碳溶解度以组装多壁 CNT，而不会沉积不需要的无定形碳。