Reversing sintering effect of Ni particles on γ-Mo2N via strong metal support interaction

Reversing the thermal induced sintering phenomenon and forming high temperature stable fine dispersed metallic centers with unique structural and electronic properties is one of the ever-lasting targets of heterogeneous catalysis. Here we report that the dispersion of metallic Ni particles into under-coordinated two-dimensional Ni clusters over γ-Mo2N is a thermodynamically favorable process based on the AIMD simulation. A Ni-4nm/γ-Mo2N model catalyst is synthesized and used to further study the reverse sintering effect by the combination of multiple in-situ characterization methods, including in-situ quick XANES and EXAFS, ambient pressure XPS and environmental SE/STEM etc. The under-coordinated two-dimensional layered Ni clusters on molybdenum nitride support generated from the Ni-4nm/γ-Mo2N has been demonstrated to be a thermally stable catalyst in 50 h stability test in CO2 hydrogenation, and exhibits a remarkable catalytic selectivity reverse compared with traditional Ni particles-based catalyst, leading to a chemo-specific CO2 hydrogenation to CO.

Reversing sintering effect of Ni particles on γ-Mo2N via strong metal support interaction

The reverse sintering effect of Ni particles under thermal treatment has been observed in the Ni/γ-Mo2N catalysts. The ab initio molecular dynamic simulation has demonstrated the redispersion of metallic Ni particles into under-coordinated two-dimensional Ni clusters over γ-Mo2N is a thermodynamically favorable process. Utilizing pre-synthesized 4 nm Ni nanoparticles as the loaded particles, a Ni-4nm/γ-Mo2N model catalyst was synthesized and used to study the reverse sintering effect by the combination of multiple in-situ characterization methods, including in-situ quick XANES and EXAFS, ambient pressure XPS and environmental SE/STEM etc. The theoretical and experimental studies both confirmed the reverse sintering effect in the Ni-γ-Mo2N system is driven by the strong metal-support interaction between Ni and γ-Mo2N. The potential application of the reverse sintering effect in heterogeneous catalysis has been realized using the high temperature favored CO2 hydrogenation reaction. The under-coordinated two-dimensional layered Ni clusters on molybdenum nitride support generated from the Ni-4nm/γ-Mo2N has been demonstrated to be a thermally stable catalyst in 50 h stability test, and exhibits a remarkable catalytic selectivity reverse compared with traditional Ni based catalyst, leading to a chemo-specific CO2 hydrogenation to CO.

Exceptionally Stable Sol-immobilization Derived Pd/SBA-15 Catalyst for Methane Combustion

Pd-based catalysts are efficient for methane combustion but impractical at high temperatures due to sintering effect. Here in, we report a thermally stable Pd/SBA-15 catalyst that was prepared by using...