The dry reforming of methane (DRM: CH4 + CO2 « 2CO + 2H2) is an emerging reaction that produces synthesis gas (CO/H2) that is an important industrial feedstock. Natural gas has transformed the energy landscape of U.S and has fast become a cheap and abundant fuel stock of the nation. Methane is the primary component of natural gas but is difficult to convert it to upgraded fuels or chemicals due to the strong C-H bond in methane (104 kcal/mol). This challenge constitutes one of the most difficult problems in heterogeneous catalysis. We have found that the Ru and its alloy (e.g., RuNi) anchored on ceria as very small clusters exhibited excellent performance for both methane activation and dry reforming of methane regarding catalytic reactivity and stability. In-situ/Operando XPD/XAFS were employed to investigate the structure-activity relationship of the catalysts, while the adsorption/desorption sites and the related surface reaction mechanisms were studied by in-situ Diffused Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The formation of RuNi alloy occurred above 400 oC during H2 pretreatment and remained intact under the DRM reaction conditions. We found that the RuNi alloy showed the highest activity and the metal-support interaction played an essential role in the activation of both methane and CO2. Coke formation was significantly suppressed over the RuNi-ceria catalyst compared with single metal Ni-Ceria, possibly due to the ease of oxygen transfer from ceria to the metal sites by the following steps: CH4(g) → C(a) + 4H(a); CO2(g) → CO(a) + O(a); C(a) + O(a) → CO(g); H(a) + H(a) → H2(g).

In-situ/operando study of ceria supported Ru and Ru alloys: Identifying the catalytic active structure for methane dry reforming

256th National Meeting (2018)

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