The conversion of methane (CH4) to value-added liquid products is a promising way to give a better answer to the increasing demand for fuels. Chemically, CH4 is the most stable hydrocarbon molecule on earth. Converting CH4 to value-added chemicals via the costly and energy intensive steam reforming lacks intrinsically the much-needed chemoselectivity and efficiency. Therefore, the challenge is to discover game-changing catalytic processes that will enable cost-effective CH4 conversion to value-added liquid chemicals. While partial electro-oxidation of CH4 to methanol (MeOH) aims at the production of valuable chemicals and its complete electro-oxidation to CO2 targets at applications in low-temperature direct CH4 fuel cells, both are expected to share some important elemental reaction steps. Moreover, preventing MeOH, or other partially oxidized value-added chemicals, from being further oxidized to CO2 is a current challenge in partial oxidation of CH4. Thus, it is fundamentally advantageous to study complete and partial oxidation of methane in parallel. Here, CuRu films and carbon coated zeolite particles (mordenite structure) with tri-copper active sites are examined as an electrocatalyst for methane electro-oxidation in CH4-saturated aqueous solution using Cyclic Voltammetry, Chronoamperometry and in situ IR spectroscopy methods. In the case of CuRu films, CV results show coincidence of the onset potential of methanol oxidation with that of Cu (I) to Cu (II) oxidation interestingly suggesting the need of multi-oxidation states for redox process to generate active oxygen species. The time-dependent IR spectra recorded during Chronoamperometry measurements also confirms the oxidation of methane on CuRu surface. We will also compare the above results measured using CuRu films with those obtained on zeolite-encaged tri-copper clusters. In summary, we will discuss the electrochemical oxidation of methane on Cu-based catalysts with some promising preliminary results which could pave the way for achieving economical direct methane conversion under mild conditions.

Study of Cu-based catalysts for methane to methanol electro-oxidation reaction

254th National Meeting (2017)

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