Tuning product selectivity ofCO₂hydrogenation byOHgroups on Pt/γ‐AlOOHand Pt/γ‐Al₂O₃catalysts

Abstract

Herein, we explore how OH groups on Pt/γ-AlOOH and Pt/γ-Al 2 O 3 catalysts affect CO 2 hydrogenation with H 2 at temperatures from 250 C to 400 C. OH groups are abundant on γ-AlOOH, but rare at Pt-(γ-AlOOH) interface which is the most favorable site for CO 2 conversion on Pt/γ-AlOOH. This makes CO 2 hydrogenation on Pt/γ-AlOOH form CO weakly bonding to γ-AlOOH, which prefers to desorption from Pt/γ-AlOOH rather than further conversion, thus enhancing CO production on Pt/γ-AlOOH. Different from Pt/γ-AlOOH, OH groups are abundant at Pt-(γ-Al 2 O 3 ) interface which is the most favorable site for CO 2 conversion on Pt/γ-Al 2 O 3 . This promotes CO 2 hydrogenation on Pt/γ-Al 2 O 3 to form CO strongly bonding to Pt, which prefers to further hydrogenation to CH 4 , and thereby increases CH 4 selectivity on Pt/γ-Al 2 O 3 . Therefore, the OH groups at metal-support interface are crucial factor influencing product distribution, and must be considered seriously when fabricating catalysts.

Electron-rich Pt anchored on covalent triazine frameworks for the selective hydrogenation of halogenated nitrobenzenes

“…For Pt/TAPB-COF, the binding energies at 71.4 and 74.8 eV correspond to Pt 0 , the peaks at 72.8 and 76.2 eV are associated with the oxidation state of Pt 2+ , and the weak peaks at 74.6 and 78.0 eV belong to Pt 4+ . 49,50 Compared to Pt/TAPB-COF, the Pt 4f XPS spectrum of Pt/TAPT-COF shows peaks shifted to lower binding energies; for example, the peaks of metallic Pt (Pt 0 ) changed to 71.0 and 74.4 eV, those of Pt 2+ moved to 72.6 and 76.0 eV, and the binding energies of Pt 4+ shifted to 73.2 and 77.6 eV. 51 These results illustrated that Pt in Pt/TAPT-COF was in an electron-rich state.…”

High Selectivity Reactive Carbon Dioxide Capture over Zeolite Dual-Functional Materials

“…Such high selectivity for CO over CH 4 is a notable result, as Pt catalysts can promote the Sabatier or reverse water-gas shift reaction depending on support interactions 20 and reaction conditions (temperature, H 2 partial pressure). 21 During the present RCC study, the H 2 :CO 2 ratio (H 2 = 43 mbar, CO 2 = trace, Ar = 814 mbar) is much higher compared to a steady-state reaction where the intended product is CO (eq 2, H 2 :CO 2 = 1). Therefore, the Pt-Na/FAU active sites suppressed extended hydrogenation pathways (that would likely terminate in CH 4 ) and enabled either H-assisted or direct dissociation of CO 2 to CO. Again, combining our experimental results with computational results from Nolen et al, we postulate that CO formed via the energetically favorable H-assisted CO 2 dissociation route.…”

Effects of molybdenum addition to activated carbon supported Ni‐based catalysts for CO2 methanation

“…However, despite extensive research and the use of sustainable and renewable energy sources, the main sources of energy remain carbon‐based fossil fuels, including natural gas, coal and oil 4–7 . Processing these non‐renewable resources produces substantial environmental pollution, primarily from gaseous emissions, including CH 4 , NOx, and COx, sometimes known as greenhouse gases (GHGs), responsible for numerous climatic problems 8 . Carbon dioxide (CO 2 ) stands out among them.…”

“…[4][5][6][7] Processing these non-renewable resources produces substantial environmental pollution, primarily from gaseous emissions, including CH 4 , NOx, and COx, sometimes known as greenhouse gases (GHGs), responsible for numerous climatic problems. 8 Carbon dioxide (CO 2 ) stands out among them. It accounts for over 80% of GHG emissions, 9 which has sparked greater interest in developing processes and methods to capture, reduce, or convert CO 2 to a source of renewable energy.…”