Synthesis of palladium-rhodium bimetallic nanoparticles for formic acid dehydrogenation
Synthesis of palladium-rhodium bimetallic nanoparticles for formic acid dehydrogenation
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DOI：
10.1016/j.jechem.2020.04.031
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发表时间：
2021-01-01
影响因子：
13.1
通讯作者：
Villa, Alberto
中科院分区：
文献类型：
--
作者：
Barlocco, Ilaria;Capelli, Sofia;Villa, Alberto
本文首次报道了以高石墨化程度的碳纳米纤维(HHT)为载体，聚乙烯醇(PVA)为保护剂，NaBH4为还原剂，通过溶胶固定化法制备了不同Pd：Rh比例的双金属Pd-Rh纳米粒子(名义摩尔比分别为80~20、60~40、40~60、20~80)和相应的Pd、Rh单金属纳米粒子。用透射电子显微镜(TEM)和电感耦合等离子体发射光谱(ICP-OES)对催化剂进行了表征。透射电子显微镜显示，Pd-Rh纳米粒子的平均粒径在3-4 nm之间，几乎没有大的团聚纳米粒子存在。对于双金属催化剂，对单个纳米颗粒的EDX-STEM分析表明，即使在所有情况下，Rh含量都低于标称的含量(计算的Pd：Rh摩尔比：90-10，69-31，49-51，40-60)，仍存在随机合金化的纳米颗粒。考察了Pd-Rh催化剂在甲酸液相脱氢制氢反应中的催化性能。结果表明，Pd-Rh摩尔比对催化剂的催化性能有很大影响。富Pd催化剂的活性高于富Rh催化剂，其中Pd-90：Rh-10的活性最高(1792h(-1))，而Pd-69：Rh-31(921h(-1))的活性最稳定。最后，以Pd-90：RH-10为代表样品，对以甲酸为供氢体的穆康酸加氢反应进行了研究，得到了较好的己二酸产率。(C)2020中科院科学出版社和大连化学物理研究所。由Elsevier B.V.和科学出版社出版。版权所有。
Herein, we report for the first time the synthesis of preformed bimetallic Pd-Rh nanoparticles with different Pd:Rh ratios (nominal molar ratio: 80-20, 60-40, 40-60, 20-80) and the corresponding Pd and Rh monometallic ones by sol immobilization using polyvinyl alcohol (PVA) as protecting agent and NaBH4 as reducing agent, using carbon nanofibers with high graphitization degree (HHT) as the desired support. The synthesized catalysts were characterized by means of Transmission Electron Microscopy (TEM) and inductively coupled plasma optical emission spectroscopy (ICP -OES). TEM shows that the average particle size of the Pd-Rh nanoparticles is the range of 3-4 nm, with the presence of few large agglomerated nanoparticles. For bimetallic catalysts, EDX-STEM analysis of individual nanoparticles demonstrated the presence of random-alloyed nanoparticles even in all cases Rh content is lower than the nominal one (calculated Pd:Rh molar ratio: 90-10, 69-31, 49-51, 40-60). The catalytic performance of the Pd-Rh catalysts was evaluated in the liquid phase dehydrogenation of formic acid to H-2. It was found that Pd-Rh molar ratio strongly influences the catalytic performance. Pd-rich catalysts were more active than Rh-rich ones, with the highest activity observed for Pd-90:Rh-10 (1792 h(-1)), whereas Pd-69:Rh-31 (921 h(-1)) resulted the most stable during recycling tests. Finally, Pd-90:Rh-10 was chosen as a representative sample for the liquid-phase hydrogenation of muconic acid using formic acid as hydrogen donor, showing good yield to adipic acid. (c) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.