Dispersed surface Ru ensembles on MgO(111) for catalytic ammonia decomposition

DOI: 10.1038/s41467-023-36339-w

Authors: Huihuang Fang (University of Oxford) , Simson Wu (University of Oxford) , Tugce Ayvali (University of Oxford) , Jianwei Zheng (University of Oxford) , Joshua Fellowes (University of Oxford) , Ping-Luen Ho (University of Oxford) , Kwan Chee Leung (University of Oxford) , Alexander Large (Diamond Light Source) , Georg Held (Diamond Light Source) , Ryuichi Kato (National Institute of Advanced Industrial Science and Technology (AIST)) , Kazu Suenaga (National Institute of Advanced Industrial Science and Technology (AIST)) , Yves Ira A. Reyes (National Tsing Hua University) , Ho Viet Thang (University of Science and Technology) , Hsin-Yi Tiffany Chen (National Tsing Hua University) , Shik Chi Edman Tsang (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature Communications , VOL 14

State: Published (Approved)
Published: February 2023

Abstract: Ammonia is regarded as an energy vector for hydrogen storage, transport and utilization, which links to usage of renewable energies. However, efficient catalysts for ammonia decomposition and their underlying mechanism yet remain obscure. Here we report that atomically-dispersed Ru atoms on MgO support on its polar (111) facets {denoted as MgO(111)} show the highest rate of ammonia decomposition, as far as we are aware, than all catalysts reported in literature due to the strong metal-support interaction and efficient surface coupling reaction. We have carefully investigated the loading effect of Ru from atomic form to cluster/nanoparticle on MgO(111). Progressive increase of surface Ru concentration, correlated with increase in specific activity per metal site, clearly indicates synergistic metal sites in close proximity, akin to those bimetallic N2 complexes in solution are required for the stepwise dehydrogenation of ammonia to N2/H2, as also supported by DFT modelling. Whereas, beyond surface doping, the specific activity drops substantially upon the formation of Ru cluster/nanoparticle, which challenges the classical view of allegorically higher activity of coordinated Ru atoms in cluster form (B5 sites) than isolated sites.

Diamond Keywords: Hydrogen Storage

Subject Areas: Chemistry, Materials, Energy


Instruments: B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS , B18-Core EXAFS

Added On: 09/02/2023 10:07

Documents:
s41467-023-36339-w.pdf

Discipline Tags:

Energy Storage Energy Physical Chemistry Catalysis Chemistry Materials Science

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) X-ray Photoelectron Spectroscopy (XPS) Extended X-ray Absorption Fine Structure (EXAFS)