(50g) Coke-Resistant Single Atom Catalyst for Methane Pyrolysis

The recent push towards sustainable hydrogen that can be produced from natural gas and supported by permanent carbon capture has sparked renewed interest in methane pyrolysis. The current catalysts used for this process deactivate easily due to coke formation on the surface of the catalyst. Coke formation is known to be caused by strong binding of CH_x intermediates and a net exothermic reaction pathway. A promising catalyst must be able to activate C−H bonds while being able to resist coke formation. Recently, single-atom and small clusters of Ni/Pt have been reported to be deposited separately on titanium nitride (TiN) plasmonic nanoparticles. The single Ni and Pt atoms favorably deposit on N-vacancy sites on the TiN surface. Supported by computational results, single-atom catalyst (SAC) formation has been confirmed through experimental TEM imaging and XPS results. Utilizing ab initio spin-polarized DFT calculations, the present work shows the simulation of intermediate C–H bond transition states and the energy barriers of the SAC nickel (Ni-TiN) or platinum (Pt-TiN) deposited on titanium nitride. The results of intermediate energy barriers for C–H bond activation on these SACs, lead to endothermic dehydrogenated fragments formation, and hence should not form any coke on the surface. The highest activation energy of the simulated reaction pathway on Ni-TiN surface was found to be 1.10 eV. This finding along with weaker binding to adsorbates and a net endothermic pathway shows that Ni-TiN is expected to resist coke formation on its surface and stay active as a catalyst. The results of both the SACs will be discussed in detail during the presentation.