Jeon Ok Sung, Lee Hyesung, Lee Kug-Seung, Paidi Vinod K, Ji Yunseong, Kwon Oh Chan, Kim Jeong Pil, Myung Jae-Ha, Park Sang Yoon, Yoo Young Joon, Lee Jin Goo, Lee Sang-Yup, Shul Yong Gun
Department of Chemical and Bio-Molecular Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749, Republic of Korea.
Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270, Republic of Korea.
ACS Appl Mater Interfaces. 2022 Mar 16;14(10):12140-12148. doi: 10.1021/acsami.1c20889. Epub 2022 Mar 3.
The strong bonding at the interface between the metal and the support, which can inhibit the undesirable aggregation of metal nanoparticles and carbon deposition from reforming of hydrocarbon, is well known as the classical strong metal-support interaction (SMSI). SMSI of nanocatalysts was significantly affected by heat treatment and reducing conditions during catalyst preparation.the heat treatment and reduction conditions during catalyst preparation. SMSI can be weakened by the decrement of metal-doped sites in the supporting oxide and can often deactivate catalysts by the encapsulation of active sites through these processes. To retain SMSI near the active sites and to enhance the catalytic activity of the nanocatalyst, it is essential to increase the number of surficial metal-doped sites between nanometal and the support. Herein, we propose a mild reduction process using dry methane (CH/CO) gas that suppresses the aggregation of nanoparticles and increases the exposed interface between the metal and support, Ni and cerium oxide. The effects of mild reduction on the chemical state of Ni-cerium oxide nanocatalysts were specifically investigated in this study. As a result, mild reduction led to form large amounts of the Ni phase at the catalyst surface of which SMSI was significantly enhanced. It can be easily fabricated while the dry reforming of methane (DRM) reaction is on stream. The superior performance of the catalyst achieved a considerably high CH conversion rate of approximately 60% and stable operation up to 550 h at a low temperature, 600 °C.
金属与载体之间界面处的强键合能够抑制金属纳米颗粒的不良团聚以及烃类重整过程中的积碳现象，这就是著名的经典强金属-载体相互作用（SMSI）。纳米催化剂的SMSI受到催化剂制备过程中的热处理和还原条件的显著影响。SMSI会因载体氧化物中金属掺杂位点的减少而减弱，并且常常通过这些过程使活性位点被包裹从而使催化剂失活。为了在活性位点附近保持SMSI并提高纳米催化剂的催化活性，增加纳米金属与载体之间表面金属掺杂位点的数量至关重要。在此，我们提出一种使用干燥甲烷（CH/CO）气体的温和还原过程，该过程可抑制纳米颗粒的团聚并增加金属与载体（镍和氧化铈）之间的暴露界面。本研究具体考察了温和还原对镍-氧化铈纳米催化剂化学状态的影响。结果表明，温和还原导致在催化剂表面形成大量镍相，其SMSI显著增强。在甲烷干重整（DRM）反应进行过程中可以轻松制备该催化剂。该催化剂的优异性能实现了约60%的相当高的CH转化率，并在600℃的低温下稳定运行长达550小时。
