Hydrogen evolution driven by heteroatoms of bidentate N-heterocyclic ligands in iron(II) complexes.

While Pt is considered the best catalyst for the electrocatalytic hydrogen evolution reaction (HER), it is evident that non-noble metal alternatives must be explored. In this regard, it is well known that the binding sites for non-noble metals play a pivotal role in facilitating efficient catalysis. Herein, we studied Fe(II) complexes with bidentate 2-(2'-pyridyl)benzoxazole (LO), 2-(2'-pyridyl)benzthiazole (LS), 2-(2'-pyridyl)benzimidazole (LNH), and 2-2'-bipyridyl (Lpy) ligands - by adding trifluoroacetic acid (TFA) to their acetonitrile solution - in order to examine how their reactivity towards protons under reductive conditions could be impacted by the non-coordinating heteroatoms (S, O, N, or none).

Transition Metal Chalcogenide Single Layers as an Active Platform for Single-Atom Catalysis.

Among the main appeals of single-atom catalysts are the ultimate efficiency of material utilization and the well-defined nature of the active sites, holding the promise of rational catalyst design. A major challenge is the stable decoration of various substrates with a high density of individually dispersed and uniformly active monatomic sites. Transition metal chalcogenides (TMCs) are broadly investigated catalysts, limited by the relative inertness of their pristine basal plane.

Spontaneous doping of the basal plane of MoS single layers through oxygen substitution under ambient conditions.

The chemical inertness of the defect-free basal plane confers environmental stability to MoS single layers, but it also limits their chemical versatility and catalytic activity. The stability of pristine MoS basal plane against oxidation under ambient conditions is a widely accepted assumption however, here we report single-atom-level structural investigations that reveal that oxygen atoms spontaneously incorporate into the basal plane of MoS single layers during ambient exposure. The use of scanning tunnelling microscopy reveals a slow oxygen-substitution reaction, during which individual sulfur atoms are replaced one by one by oxygen, giving rise to solid-solution-type 2D MoSO crystals.

Sulfur uptake determination on Ni containing molybdena-alumina samples by radioisotope tracer technique.

Five solid oxides, used as hydrodesulfurization catalysts (Al(2)O(3) supported Ni, MoO(x), Ni-MoO(x)-s of different Ni:Mo ratio) were sulfided by [(35)S]H(2)S. Amounts of the total, reversible and irreversible sulfur uptakes were determined measuring the change of gas phase radioactivity during exposure [(35)S]H(2)S to the oxides, and compared with the amounts determined measuring radioactivity of the sulfided samples. The S/(Ni+Mo) values determined by X-ray photoelectron spectroscopy (XPS) were in satisfactory agreement with the results obtained by radiosulfur.