Location of Co and Ni promoter atoms in multi-layer MoS 2 nanocrystals for hydrotreating catalysis

•Industrial-style hydrotreating catalysts are examined by STEM-EEL spectrum imaging.•Element maps resolve Co and Ni atoms at edges of multi-layer MoS2 nanocrystals.•The edge-located Co and Ni atoms are proposed to promote hydrotreating reactions differently.