Oxidative coupling of methane (OCM) is one of the most promising approaches to produce ethylene and ethane (C₂-hydrocarbons) in the post-oil era. The MnO_x-Na₂WO₄/SiO₂ system shows promising OCM performance, which can be further enhanced by cofed steam. However, the positive effect of steam on C₂-hydrocarbons selectivity practically disappears above 800 °C. In the present study, we demonstrate that the use of SiC as a support for MnO_x-Na₂WO₄ is beneficial for achieving high selectivity up to 850 °C. Our sophisticated kinetic tests using feeds without and with steam revealed that the steam-mediated improvement in selectivity to C₂-hydrocarbons is due to the inhibition of the direct CH₄ oxidation to carbon oxides because of the different enhancing effects of steam on the rates of CH₄ conversion to C₂H₆ and CO/CO₂. Other descriptors of the selectivity improvement are MnO_x dispersion and the catalyst specific surface area. The knowledge gained herein may be useful for optimizing OCM performance through catalyst design and reactor operation.

Methylcyclohexane (MCH) serves as an ideal hydrogen carrier in hydrogen storage and transportation process. In the continuous production of hydrogen from MCH dehydrogenation, the rational design of energy-efficient catalytic way with good performance remains an enormous challenge. Herein, an internal electric heating (IEH) assisted mode was designed and proposed by the directly electrical-driven catalyst using the resistive heating effect. The Pt/Al₂O₃ on Fe foam (Pt/Al₂O₃/FF) with unique three-dimensional network structure was constructed. The catalysts were studied in a comprehensive way including X-ray diffraction (XRD), scanning electron microscopy (SEM)-mapping, in situ extended X-ray absorption fine structure (EXAFS), and in situ CO-Fourier transform infrared (FTIR) measurements. It was found that the hydrogen evolution rate in IEH mode can reach up to above 2060 mmol·g_Pt⁻¹·min⁻¹, which is 2–5 times higher than that of reported Pt based catalysts under similar reaction conditions in conventional heating (CH) mode. In combination with measurements from high-resolution infrared thermometer, the equations of heat transfer rate, and reaction heat analysis results, the Pt/Al₂O₃/FF not only has high mass and heat transfer ability to promote catalytic performance, but also behaves as the heating component with a low thermal resistance and heat capacity offering a fast temperature response in IEH mode. In addition, the chemical adsorption and activation of MCH molecules can be efficiently facilitated by IEH mode, proved by the operando MCH-FTIR results. Therefore, the as-developed IEH mode can efficiently reduce the heat and mass transfer limitations and prominently boost the dehydrogenation performance, which has a broad application potential in hydrogen storage and other catalytic reaction processes.

Propylene is a significant basic material for petrochemicals such as polypropylene, propylene oxide, etc. With abundant propane supply from shale gas, propane dehydrogenation (PDH) becomes extensively attractive as an on-purpose propylene production route in recent years. Nitrogen-doped carbon (NC) nanopolyhedra supported cobalt catalysts were synthesized in one-step of ZIF-67 pyrolysis and investigated further in PDH. XPS, TEM and N₂ adsorption-desorption were used to study the influence of carbonization temperature on as-prepared NC supported cobalt catalysts. The temperature is found to affect the cobalt phase and nitrogen species of the catalysts. And the positive correlation was established between Co⁰ proportion and space time yield of propylene, indicating that the modulation of carbonization temperature could be important for catalytic performance.