In Situ Generation of the Cu@3D-ZrO x Framework Catalyst for Selective Methanol Synthesis from CO 2 /H 2

作者：Tangkang Liu, Xinlin Hong, Guoliang Liu · 发表于：ACS Catalysis · 年份：2019 · DOI：10.1021/acscatal.9b03738 · 被引用次数：149 · 研究领域：Catalysts for Methane Reforming、Catalytic Processes in Materials Science、Metal-Organic Frameworks: Synthesis and Applications

Cu-based catalysts have been widely studied for direct hydrogenation of CO 2 to methanol. Their activities quite depend on the amount of exposed active sites (e.g., Cu-oxide interfaces), which can be tuned by the particle size as well as porosity. Here, we report an active, selective, and stable Cu@ZrO x catalyst with a three-dimensional (3D) porous framework structure via the in situ reconstruction of size-confined Cu@UiO-66. The optimized CU-0.5-300 catalyst shows a high methanol selectivity of 78.8% at a conversion of 13.1% at 260 °C, 4.5 MPa, giving a methanol space-time yield of 796 g·kg cat –1 ·h –1 . It also shows long-term stability for 105 h in a time-on-stream test. Such good performance benefits from abundant Cu–ZrO x interfaces and a stable 3D ZrO x framework. During the reaction, ZrO x species in situ evolves from the unstable Zr-oxide cluster (the building unit of UiO-66) or amorphous ZrO 2 to a stable tetragonal ZrO 2 phase, but strong metal–support interaction (SMSI) at Cu–ZrO x interfaces retains. The SMSI enables the formation of Cu + at the ZrO 2 surface, which is strongly associated with the active sites for methanol synthesis. In situ diffuse-reflectance infrared Fourier transform spectroscopy studies reveal methanol synthesis which follows a HCOO-intermediated pathway. It is believed that this work provides an “in situ reconstruction” strategy to fabricate a practical Cu@ZrO x framework catalyst for methanol production.