Observation of Adsorbed Hydrogen Species on Supported Metal Catalysts by Inelastic Neutron Scattering
Observation of Adsorbed Hydrogen Species on Supported Metal Catalysts by Inelastic Neutron Scattering
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通过非弹性中子散射观察负载金属催化剂上吸附的氢形态
DOI：
10.1007/s11244-021-01448-7
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发表时间：
2021
影响因子：
3.6
通讯作者：
Tanaka Tsunehiro
中科院分区：
文献类型：
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作者：
Yoshida Hisao;Yamamoto Akira;Hosokawa Saburo;Yamazoe Seiji;Kikkawa Soichi;Hara Kenji;Nakamura Mitsutaka;Kamazawa Kazuya;Tanaka Tsunehiro
吸附在催化剂表面的氢物种是许多催化反应中的重要活性中间体，对它们的详细分析是理解催化的必要条件。非弹性中子散射（INS）由于氢原子极大的非相干中子散射截面，可以直接和选择性地观察氢物种。本文采用自行设计的样品池，用原位INS光谱法研究了几种以氧化铝和炭黑为载体的非均相贵金属催化剂上吸附的氢物种。新设计的双壁长池给出了清晰的INS光谱，具有较小的弹性散射。具有不同粒径的Pt、Pd和Rh金属纳米颗粒的三种氧化铝负载的金属催化剂在强度和谱带分布方面表现出不同的INS光谱。对金属纳米颗粒和氧化铝表面上的H物种的观察揭示了它们的性质。此外，氢原子储存在钯纳米粒子被观察到作为钯氢化物。相比之下，由炭黑负载的Pt催化剂上的H物种被发现强烈吸附在碳载体上。这些H物种的性质取决于贵金属的性质和载体材料的性质。
Adsorbed hydrogen (H) species on catalyst surfaces are important active intermediates in many catalytic reactions and detailed analyses of them are necessary to understand the catalyses. Inelastic neutron scattering (INS) enables direct and selective observation of H species due to the extremely large incoherent neutron scattering cross section of a hydrogen atom. In the present study, the adsorbed H species on some heterogeneous precious metal catalysts supported by alumina and carbon black were investigated by in situ INS spectroscopy with a newly designed sample cell. The newly designed double-walled long cell gave clear INS spectra with less elastic scattering. Three alumina-supported metal catalysts having Pt, Pd, and Rh metal nanoparticles with different particle sizes exhibited different INS spectra in intensities and band distribution. Observation of the H species on the metal nanoparticles and the alumina surface revealed their properties. In addition, the H atoms stored in Pd nanoparticles were observed as palladium hydride. In contrast, the H species on a Pt catalyst supported by carbon black were found to be strongly adsorbed on the carbon support. The properties of these H species were dependent on both the properties of the precious metals and those of the support materials.