College of Materials and Energy, South China Agricultural University, Guangzhou 510640, China.
ACS Appl Mater Interfaces. 2021 May 12;13(18):21482-21498. doi: 10.1021/acsami.1c05350. Epub 2021 Apr 30.
Aromatics from selective hydrodeoxygenation (HDO) of biomass-derived bio-oil are an ideal feedstock for replacing industrial fossil products. In this study, biochar-modified Hβ/Ni-V catalysts were prepared and tested in the atmospheric HDO of guaiacol and bio-oil to produce aromatics. Compared with unmodified Hβ/Ni-V, higher HDO activity was achieved in catalysts with all kinds of biochar modifications. Especially, the pine nut shell biochar (PB)-modified PB-Hβ-8/Ni-V showed the highest selectivity to aromatics (69.17%), mainly including benzene and toluene. Besides, under the conditions of 380 °C and weight hourly space velocity (WHSV) of 0.5 h, the cleavage of C-OH (C means the carbon in the benzene ring) was promoted to form more aromatics. Moreover, great recyclability (58.77% aromatics for the reactivated run-3 test) and efficient HDO of bio-oil (44.9% aromatic yield) were also achieved. Based on the characterization results, the enhanced aromatic selectivity of PB-Hβ-8/Ni-V was attributed to the synergetic effect between PB and Hβ/Ni-V. In detail, a stable surface migrated-carbon layer was formed on Hβ/Ni-V via the metal catalytic chemical vapor deposition (CVD) process of the pyrolysis PB volatiles. Simultaneously, a carbothermal reduction driven by the migrated-carbon took place to decorate the surface metals, obtaining more Ni and V active sites. With this synergism, increased Ni sites promoted H adsorption and dissociation, which improved the hydrogenation activity. Furthermore, the higher affinity of the reactant and increased oxygen vacancies both contributed to enhancing the selective surface adsorption of oxygenous groups and the cleavage of the C-OH bond, thus improving the deoxygenation activity. Therefore, the HDO activity was improved to form more target aromatics over biochar-modified catalysts. This work highlighted a potential avenue to develop economic and environmental catalysts for the upgrading of bio-oil.
从生物质衍生生物油中选择性加氢脱氧（HDO）得到的芳烃是替代工业化石产品的理想原料。在这项研究中，制备了生物炭修饰的 Hβ/Ni-V 催化剂，并将其用于测试愈创木酚和生物油的常压 HDO 以生产芳烃。与未修饰的 Hβ/Ni-V 相比，各种生物炭修饰的催化剂都表现出更高的 HDO 活性。特别是，松仁壳生物炭（PB）修饰的 PB-Hβ-8/Ni-V 对芳烃（主要包括苯和甲苯）的选择性最高，达到 69.17%。此外，在 380°C 和重时空速（WHSV）为 0.5 h 的条件下，促进了 C-OH 的断裂（C 代表苯环中的碳），形成了更多的芳烃。此外，还实现了良好的可循环性（第 3 次重复测试的芳烃收率为 58.77%）和生物油的高效 HDO（芳烃收率为 44.9%）。基于表征结果，PB-Hβ-8/Ni-V 增强的芳烃选择性归因于 PB 和 Hβ/Ni-V 之间的协同效应。具体来说，通过热解 PB 挥发分的金属催化化学气相沉积（CVD）过程，在 Hβ/Ni-V 上形成了稳定的表面迁移碳层。同时，通过迁移碳驱动的碳热还原作用，对表面金属进行了修饰，获得了更多的 Ni 和 V 活性位。通过这种协同作用，增加的 Ni 位促进了 H 的吸附和解离，提高了加氢活性。此外，反应物的更高亲和力和增加的氧空位都有助于增强含氧基团的表面选择性吸附和 C-OH 键的断裂，从而提高脱氧活性。因此，在生物炭修饰的催化剂上，通过提高 HDO 活性形成了更多的目标芳烃。这项工作为开发用于生物油升级的经济环保催化剂提供了一个潜在途径。
