What Is the Active Structure for High-Temperature Direct Dehydrogenative Conversion of Methane by the Supported NiP Catalysts─An in Situ XAFS Study

Abstract

SiO 2 -supported NiP catalysts exhibit high activity for the direct dehydrogenative conversion of methane (DCM) to hydrocarbons, such as ethylene, ethane, acetylene, and propylene, at 1173 K. To investigate the real active structure of the SiO 2supported NiP catalysts at high temperature, in situ X-ray absorption fine structure (XAFS) experiments were conducted under the DCM reaction conditions. XAFS results showed that all of the SiO 2 -supported NiP catalysts with atomic ratios of Ni/P = 1:1, 1:2, 1:3, and 1:4 mainly showed a similar Ni 2 P structure. The Ni 2 P structure was stable under the DCM reaction conditions. The high stability of the Ni 2 P structure ensured robust catalysis for DCM. The high catalytic performance of Ni 2 P was discussed.