A\nKnowledge-Based Molecular Single-Source Precursor\nApproach to Nickel Chalcogenide Precatalysts for Electrocatalytic\nWater, Alcohol, and Aldehyde Oxidations

The development and\ncomprehensive understanding of nickel chalcogenides\nare critical since they constitute a class of efficient electro(pre)catalysts\nfor the oxygen evolution reaction (OER) and value-added organic oxidations.\nThis study introduces a knowledge-based facile approach to analogous\nNiE (E = S, Se, Te) phases, originating from molecular β-diketiminato\n[Ni<sub>2</sub>E<sub>2</sub>] complexes and their application for\nOER and organic oxidations. The recorded activity trends for both\ntarget reactions follow the order NiSe > NiS > NiTe. Notably,\nNiSe\ndisplayed efficient performance for both OER and the selective oxidation\nof benzyl alcohol and 5-hydroxymethylfurfural, exhibiting stability\nin OER for 11 days under industrially pertinent conditions. Comprehensive\nanalysis, including quasi <i>in situ</i> X-ray absorption\nand Raman spectroscopy, in combination with several <i>ex situ</i> techniques, revealed a material reconstruction process under alkaline\nOER conditions, involving chalcogen leaching. While NiS and NiSe experienced\nfull chalcogen leaching and reconstruction into Ni<sup>III/IV</sup> oxyhydroxide active phases with intercalated potassium ions, the\ntransformation of NiTe is incomplete. This study highlights the structure–activity\nrelationship of a whole series of analogous nickel chalcogenides,\ndirectly linking material activity to the availability of active sites\nfor catalysis. Such findings hold great promise for the development\nof efficient electrocatalysts for a wide range of applications, impacting\nvarious industrial processes and sustainable energy solutions.