Asymmetric Dual-Atom Ru Anchored in Boron Nitride Nanolayer Triggers Mechanism Transition for Stable Dry Reforming
Yani Zhang1, Huibin Wang1, Mingjia Zhang1,2
1Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
Abstract:
Methane dry reforming represents a promising approach to reduce greenhouse gas emissions and to utilize natural gas for value-added products. However, this process is challenged by limited reactivity and severe coking at low temperatures. Here, we report a dual-atom ruthenium catalyst anchored in a boron nitride nanolayer. The spatially distinct coordination of the Ru atomic pair gives rise to the asymmetric charge distribution of the active center. The synergy effect of Ru dimer achieves the CH4 and CO2 conversions of 69% and 76% at 650 °C, respectively, which are near thermodynamic equilibrium, while maintaining an exceptional stability of 1000 h at 600 °C with negligible coking. Mechanism studies reveal that an electron-deficient Ru site facilitates the C-H cleavage in CH4 via an enhanced polarization effect, while another electron-rich Ru site promotes CO2 activation with a bidentate adsorption configuration. Furthermore, this unique dual-atom Ru structure enables a Langmuir-Hinshelwood pathway with a reduced barrier of the coupling reaction between CH4 and CO2 to form *CH2O intermediate and produce syngas rather than excessive C-C binding and coke deposition. This work provides a strategy for designing multifunctional catalysts to solve the seesaw issue of reactivity and stability for methane dry reforming.
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