PdIn intermetallic nanoparticles for the Hydrogenation of CO2 to Methanol
PdIn intermetallic nanoparticles for the Hydrogenation of CO2 to Methanol
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DOI：
10.1016/j.apcatb.2017.07.069
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发表时间：
2018-01-01
影响因子：
22.1
通讯作者：
Williams, Charlotte K.
中科院分区：
文献类型：
--
作者：
Garcia-Trenco, Andres;Regoutz, Anna;Williams, Charlotte K.
如果能够开发出高效的催化剂，CO2直接加氢制甲醇可以提供显着的环境效益。在此，Pd-In纳米粒子作为该反应的催化剂显示出良好的性能。通过在高沸点溶剂（角鲨烷）中热分解Pd（乙酸酯）2和In（乙酸酯）3前体，然后使用稀H-2气体（210摄氏度）还原来合成无负载纳米颗粒。调节两种金属前体的比例允许获得具有不同相组成的5- 10 nm纳米颗粒，包括金属Pd（0）、In 2 O3和金属间PdIn。液相甲醇合成实验（50巴，210摄氏度，H2：CO2 =3：1）将金属间PdIn纳米颗粒鉴定为最有效的。与常规的非均相Cu/ZnO/Al 2 O3催化剂（分别为900和540 μ mol mmol（PdInorCuZnAl）（-1）h（-1））相比，该催化剂表现出高约70%的甲醇速率（归一化为总摩尔金属含量）。此外，最佳Pd/In催化剂在所研究的整个温度范围内（190-270 ℃）显示出改善的甲醇选择性，在270 ℃下达到>80%的选择性，而参考Cu/ZnO/Al 2 O3催化剂仅为45%。实验表明，稳定性的改善;甲醇生产率下降了20%后，运行120小时的最佳PdIn基相比，30%的Cu/ZnO/Al 2 O3催化剂（25小时后）。通过XRD、HR-TEM、STEM-EDX和XPS表征，最佳催化剂由类似于8 nm的纳米颗粒组成，该纳米颗粒包含表面富含In的PdIn金属间相。最佳催化剂的催化后分析表明，保留了相同的PdIn双相，而纳米颗粒尺寸仅略有增加。(C)2017作者由爱思唯尔公司出版
Direct hydrogenation of CO2 to methanol could offer significant environmental benefits, if efficient catalysts can be developed. Here, bimetallic Pd-In nanoparticles show good performance as catalysts for this reaction. Unsupported nanoparticles are synthesised by the thermal decomposition of Pd(acetate)2 and In(acetate)3 precursors in a high boiling point solvent (squalane), followed by reduction using dilute H-2 gas (210 degrees C). Adjusting the ratio of the two metallic precursors allow access to 5-10nm nanoparticles with different phase compositions, including metallic Pd(0), In2O3 and intermetallic Pdln. Liquid phase methanol synthesis experiments (50 bar, 210 degrees C, H-2:CO2 =3:1) identify the intermetallic Pdln nanoparticles as the most efficient. The catalysts exhibit around 70% higher methanol rates (normalised to the overall molar metal content) compared to the conventional heterogeneous Cu/ZnO/Al2O3 catalyst (900 and 540 p,mol mmol(PdlnorCuZnAl)(-1)h(-1), respectively). In addition, the optimum Pd/In catalyst shows an improved methanol selectivity over the whole temperature range studied (190-270 degrees C), reaching >80% selectivity at 270 degrees C, compared to only 45% for the reference Cu/ZnO/Al2O3 catalyst. Experiments showed an improvement in stability; the methanol production rate declined by 20% after 120 h run for the optimum Pdln-based compared with 30% for the Cu/ZnO/Al2O3 catalyst (after 25 h). The optimum catalyst consists of similar to 8 nm nanoparticles comprising a surface In-enriched Pdln intermetallic phase as characterised by XRD, HR-TEM, STEM-EDX and XPS. Post-catalysis analysis of the optimum catalyst shows that the same Pdln bimetallic phase is retained with only a slight increase in the nanoparticle size. (C) 2017 The Authors. Published by Elsevier B.V.