Effect of cobalt doping-regulated crystallinity in nickel-iron layered double hydroxide catalyzing oxygen evolution

Origin of the Universal Potential-Dependent Organic Oxidation on Nickel Oxyhydroxide

“…To further glean the active species on NiO x (OH) 2– x , we carried out in situ surface-enhanced Raman spectroscopy (SERS) on a Ni­(OH) 2 -coated roughened Au electrode (Figure ). Surprisingly, we observed two Raman bands of 476 and 556 cm –1 that are often characteristic of Ni III -O e g and A 1g bands at much more negative potentials than the bulk Ni redox transition (1.26 and 1.32 V vs RHE). ,− This species was not observed on a glassy carbon electrode where surface enhancement was absent (Figure S3) and was not derived from the roughened Au electrode (Figure S4). It demonstrates the presence of surface Ni oxidation (especially the surface contacting the Au electrode) much before the bulk Ni transition (we designated this surface species as NiO x (OH) 2– x (surface), while the rest of the NiO x (OH) 2– x was designated as NiO x (OH) 2– x (bulk)).…”

“…The emerging hydrogen economy for sustainable energy systems has increased the demand for more efficient hydrogen production technologies. − One alternative to the prominent water splitting technologies is the paired electrolysis via cathodic hydrogen evolution and anodic organic oxidation, especially naturally available alcohols, aldehydes, and amines. − This route can not only replace the low-valued oxygen product with the value-added carboxylic acid or nitrile products but also require lower energy cost due to the higher reactivities of the organics, which together decrease the composite cost of hydrogen. ,, Nickel oxyhydroxide (NiO x (OH) 2– x , x = 1–2 depending on the oxidation state of Ni and phase structure of the pristine Ni­(OH) 2 ) is one of the most active catalysts toward the electrochemical selective oxidation of these organics. − ,,,− Its low cost, facile accessibility, scalable production, and widespread use in industrial alkaline electrolyzers have promoted the research focus as the potential electrocatalyst candidate. Thus, understanding the electrocatalytic mechanism on the nickel oxyhydroxide surfaces has become utterly important for the rational design of next-generation electrocatalysts with high efficiency and selectivity for organic oxidation …”

Construction of a NiFe-LDH catalyst with a three-dimensional unified gas diffusion layer structure via a facile acid etching route for the oxygen evolution reaction

“…2f demonstrated that the NFF-H 2 SO 4 exhibited a lower chargetransfer resistance (R ct ) compared with that of NFF, which implied a faster interfacial faradaic reaction process. 46 Generally speaking, the performance of the NFF had been remarkably improved in all aspects merely by soaking in H 2 SO 4 within 5 minutes, which were embodied in the following aspects: (1) more abundant and powerful active sites; (2) faster reaction kinetics; (3) faster electron transfer between the catalyst and the reactants. In addition, nickel, iron and sulfuric acid, as cheap and abundant industrial raw materials, made this simple and fast method very suitable for commercialization.…”

Corrosion engineering approach to rapidly prepare Ni(Fe)OOH/Ni(Fe)Sx nanosheet arrays for efficient water oxidation

“…Among them, Ni–Fe (oxy)hydroxides and sulfides have been demonstrated to have state-of-the-art electrocatalytic performance for OER. 11–15…”

“…Among them, Ni-Fe (oxy) hydroxides and suldes have been demonstrated to have stateof-the-art electrocatalytic performance for OER. [11][12][13][14][15] As the mainstream methods, solvothermal and electrodeposition have been developed to prepare Ni-Fe (oxy)hydroxides and suldes. [15][16][17][18][19] However, these synthetic strategies are difficult to scale up to prepare large-area electrodes compatible with industrial electrocatalytic electrolyzers.…”