Coordination environment tuning of nickel sites by oxyanions to optimize methanol electro-oxidation activity

Abstract

To achieve zero-carbon economy, advanced anode catalysts are desirable for hydrogen production and biomass upgrading powered by renewable energy. Ni-based non-precious electrocatalysts are considered as potential candidates because of intrinsic redox attributes, but in-depth understanding and rational design of Ni site coordination still remain challenging. Here, we perform anodic electrochemical oxidation of Ni-metalloids (NiPx, NiSx, and NiSex) to in-situ construct different oxyanion-coordinated amorphous nickel oxyhydroxides (NiOOH-TOx), among which NiOOH-POx shows optimal local coordination environment and boosts electrocatalytic activity of Ni sites towards selective oxidation of methanol to formate. Experiments and theoretical results demonstrate that NiOOH-POx possesses improved adsorption of OH* and methanol, and favors the formation of CH3O* intermediates. The coordinated phosphate oxyanions effectively tailor the d band center of Ni sites and increases Ni-O covalency, promoting the catalytic activity. This study provides additional insights into modulation of active-center coordination environment via oxyanions for organic molecules transformation.

Electrochemical Conversion of Alcohols into Acidic Commodities on Nickel Sulfide Nanoparticles

“…Compared with that of pristine NiOOH, the d electrons of Ni in the SO x -decorated NiOOH significantly concentrate around the Fermi level, thus improving the electroconductivity and electron transfer (Figure S10b). Thus, the higher performance of the NiS-based electrode may be in part associated with the presence of SO x species during the electrocatalytic process, in agreement with previous publications. ,, …”

“…Thus, the higher performance of the NiS-based electrode may be in part associated with the presence of SO x species during the electrocatalytic process, in agreement with previous publications. 29,60,61 To calculate the Faradaic efficiency for the ethanol and methanol conversion process, the electrolyte obtained at the end of CA testing was analyzed by the means of IC. As shown in Figures 4b and S8b, a downward peak for water was presented at 2.8 min, and upward peaks at 4.3 and 4.8 min, corresponding to the acetate and formate, were observed as the main products of the ethanol and methanol oxidation, respectively.…”

“…In addition, the presence of the ions produced from the chalcogen oxidation, e.g., sulfates, can change the local coordination environment of the active species regulating the adsorption of the reactants/intermediates/products. 29 T h i s c o n t e n t i s To maximize cost-effectiveness, catalysts need to be produced in the form of nanometer-sized particles using cost-effective and scalable methods. In this direction, the Brutchey group has pioneered an "alkahest solvent" method for the high-throughput synthesis of chalcogenide nanoparticles (NPs).…”

“…Compared with monometallic Ni electrocatalysts, the use of Ni chalcogenides has been demonstrated to improve performance toward the OER, − methanol oxidation reaction (MOR), − and ethanol oxidation reaction (EOR), − among others. − This improvement is generally ascribed to a bulk-driven modulation of the surface electronic structures of the Ni catalyst, accelerating the metal regeneration in an alkaline medium. In addition, the presence of the ions produced from the chalcogen oxidation, e.g., sulfates, can change the local coordination environment of the active species regulating the adsorption of the reactants/intermediates/products …”

l-Lysine derived fabrication of Cu@Ni core–satellite nanoassemblies as efficient non-Pt catalysts for the methanol oxidation reaction

“…Direct methanol fuel cells (DMFCs) are widely recognized as a promising power supply due to their sufficient energy density, low operating temperature and reduced pollutant emission. 1–4 In DMFCs, the anodic methanol oxidation reaction (MOR, CH 3 OH + H 2 O → CO 2 + 6H + + 6e − ) is the key step to determine the total conversion efficiency, where precious-group metals (PGMs, e.g. Pt, Pd, Rh) and their alloys primarily exhibit superior intrinsic activity.…”