Functional CeO_x Stabilized Metallic Ni Catalyst Supported on Boron Nitride for Durable Partial Oxidation of Methane to Syngas at High Temperature

Enhancing catalyst durability is a critical concern in the partial oxidation of methane (POM) to syngas since the reaction is operated at high temperatures (>600 °C). Alongside sintering and coke deposition, the deactivation of the supported Ni catalyst is often due to the in situ oxidation of active metallic nanoparticles into inactive cations during the POM reaction. Herein, a Ni/BN catalyst was developed by introducing functional CeO_x as a promoter to stabilize the Ni sites. The optimized 4Ni/7.5Ce/BN catalyst, comprising 4 wt % Ni and 7.5 wt % Ce on BN, exhibits enhanced stability during continuous testing at 600 °C for 125 h without any deactivation, which is comparable to that of noble metal catalysts. Comprehensive investigations reveal that maintaining the metallic state of Ni under reaction atmosphere is crucial for the stability of the catalyst. The construction of CeO_x on BN effectively inhibits migration and oxidation of the catalytically active Ni⁰ species.