Controlling CO₂ Hydrogenation Selectivity by Metal‐Supported Electron Transfer

Abstract

Tuning CO 2 hydrogenation selectivity to obtain targeted value-added chemicals and fuels has attracted increasing attention. However,af undamental understanding of the way to control the selectivity is still lacking, posing achallenge in catalyst design and development. Herein, we report our new discovery in ambient pressure CO 2 hydrogenation reaction where selectivity can be completely reversed by simply changing the crystal phases of TiO 2 support (anatase-or rutile-TiO 2) or changing metal loadings on anatase-TiO 2 .O perando spectroscopyand NAP-XPS studies reveal that the determining factor is adifferent electron transfer from metal to the support, most probably as ar esult of the different extents of hydrogen spillover,w hichc hanges the adsorption and activation of the intermediate of CO.Based on this new finding,wecan not only regulate CO 2 hydrogenation selectivity but also tune catalytic performance in other important reactions,t hus opening up ad oor for efficient catalyst development by rational design.

Electronic modulation of metal-support interactions improves polypropylene hydrogenolysis over ruthenium catalysts

“…3b). The direct charge transfer from Ru to TiO 2 CB leads to a partial reduction of TiO 2 , as reported in CO 2 reduction 46 . Ru δ+ -H − pairs upon H 2 adsorption were also reported on Ru/carbon nanotubes 47 .…”

Enhanced catalytic activity of CO2 hydrogenation to CO over sulfur-containing Ni/ZrO2 catalysts: support size effect

“…It demonstrates that the Nibased catalysts synthesized in this work possess superior catalytic performance compared to those reported in the literature. [17][18][19]40 Furthermore, compared with the method of Ni-based catalyst reacting with trace amounts of H 2 S mentioned above, 21 our catalyst can achieve 100% CO selectivity and high CO 2 conversion at the beginning of the reaction without going through a 50 h methanation reaction and catalyst deactivation process, which well solves the problems of the low CO 2 conversion and long selective modulation time in the original method. Ni/ZrO 2 without sulfur (named Ni/ZrO 2 -80 S-free ) has also been prepared and tested, for comparing the catalytic performance of Ni/ZrO 2 -80.…”

“…For Ni-based catalysts, the desorption energy of CO* is relatively high, resulting in further hydrogenation to CH 4 , which greatly reduces the selectivity of CO in the final product. 3 In order to modulate the CO 2 hydrogenation product of Ni-based catalysts from CH 4 to CO, researchers have proposed the following three kinds of regulation methods: (1) construction of monatomic catalysts; 15,16 (2) modulation of metal-support interaction (MSI); 17,18 (3) preparation of bimetallic catalysts. 19,20 However, the disadvantage of the above selective regulation methods is that the CO 2 conversion rate of Ni-based catalysts prepared by the first two methods are relatively low (B10% at 500 1C), while the preparation methods of bimetallic catalysts are complex and lack universality.…”

Heterogeneous Catalysis for CO2 Conversion into Chemicals and Fuels

“…With this knowledge, one can improve CO selectivity by decreasing the coordination number of supported metals or using metals at the lower right corner of the transition metal series. This theory likely explains the preferred formation of CO versus methane over TiO 2 -supported metals with low loadings [43,44] and Au-based catalysts [45].…”