Formation of CH₄ at the Metal‐Support Interface of Pt/Al₂O₃ During Hydrogenation of CO₂: Operando XAS‐DRIFTS Study

Abstract

The adsorbed intermediates on supported metal catalysts govern their catalytic activity and selectivity, although it is difficult to quantify them under the working states. We monitored the adsorbed species on Al 2 O 3 -and SiO 2 -supported Pt nanoparticle catalyst during hydrogenation of CO 2 and elucidated the CH 4 -formation sites at the metal-support interface of Pt/Al 2 O 3 , by using a combination of X-ray absorption spectroscopy (XAS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) with product analysis (oper-ando XAS-DRIFTS). Pt L 3 -and L 2 -edge X-ray absorption near edge structure spectra quantified the unoccupied states of Pt species, revealing that both of hydrogen and CO species adsorbed on the Pt surface of Pt/Al 2 O 3 , whereas a relatively smaller amount of hydrogen species adsorbed on Pt/SiO 2 . The DRIFTS and reaction results indicated that the CO species coadsorbed with hydrogen species on the perimeter Pt sites were hydrogenated to CH 4 at the interface between Pt particles and Al 2 O 3 surface.

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

“…Above 150 °C, CO began to form (along with H 2 O), aligning with our expectation that CO 2 activation would only begin after Pt sites were activated. 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 and reaction conditions (temperature, H 2 partial pressure) . 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 , H 2 :CO 2 = 1).…”

Selective CO2hydrogenation over zeolite-based catalysts for targeted high-value products

“…CH 3 O, CHO, CH 3 OH), 27,36 which are subsequently transferred to zeolites where they are converted into olens and aromatics. 91 Transition metals such as Ni, [92][93][94] Rh, [95][96][97] Pd, 98 Pt 5,99 are effectively used for CO 2 methanation (as shown in eqn (5) and Fig. 2d-e).…”

“…The use of CO 2 as feedstock to produce hydrocarbons (such as CH 4 , 5,6 light olens, 7 aromatics) and chemicals (such as methanol, 8-10 ethanol, 11,12 formic acid, 13 esters 14 ) is not only Penghui Yan obtained his MSc from University of Chinese Academy of Sciences in 2013 and PhD degree in Chemical Engineering from the University of Newcastle in 2020. He was employed at Shaanxi Yanchang Petroleum Group in 2013-2014, contributing to the pilot projects involving fast pyrolysis of coal and biomass.…”

“…The use of CO 2 as feedstock to produce hydrocarbons (such as CH 4 , 5,6 light olefins, 7 aromatics) and chemicals (such as methanol, 8–10 ethanol, 11,12 formic acid, 13 esters 14 ) is not only a complementary alternative to fossil-derived fuel and chemicals, but it also facilitates the mitigation of CO 2 emission. Consequently, it has garnered widespread attention from both scientific researchers and industrial communities.…”

Catalytic Synthesis of CO by Combining CO2 Capture and Hydrogenation over Three-Dimensional Ni/CaO Networks

“…Among different hydrogenation reactions, CO 2 hydrogenation by a reverse water gas shift (RWGS) is considered an important reaction in C1 chemistry for the tunable H 2 /CO ratio in the products, which can be applied for further conversion to downstream products, such as methanol, Fischer–Tropsch synthesis, and dimethyl ether . Although some noble metals, such as Ru, Rh, Pd, and Pt, − have excellent activities for CO 2 hydrogenation even at low temperatures, the high cost of catalyst production limits the industrial application of the noble metal-based catalysts. Ni-based catalysts should be promising candidates for the ICCU process because of their effective cost and high activity for CO 2 hydrogenation. − Recently, Jo et al − tried to optimize the reaction temperatures for methanation, RWGS , and dry reforming of methane (DRM) processes to obtain CH 4 , CO, and CO/H 2 synthetic gas, respectively, using Ni/CaO catal-sorbents.…”