Boronization‐Induced Ultrathin 2D Nanosheets with Abundant Crystalline–Amorphous Phase Boundary Supported on Nickel Foam toward Efficient Water Splitting

Abstract

The conversion of crystalline metal–organic frameworks (MOFs) into metal compounds/carbon hybrid nanocomposites via pyrolysis provides a promising solution to design electrocatalysts for electrochemical water splitting. However, pyrolyzing MOFs generally involves a complex high‐temperature treatment, which can destroy the coordinated surroundings within MOFs, and as a result not taking their full advantage of their electrolysis properties. Herein, a simple and room‐temperature boronization strategy is developed to convert nickel zeolite imidazolate framework (Ni‐ZIF) nanorods into ultrathin Ni‐ZIF/NiB nanosheets with abundant crystalline–amorphous phase boundaries. The combined experiment, and theoretical calculation results disclose that the ultrathin thickness allows fast electron transfer and ensures increased exposure of surface coordinatively unsaturated active sites while the crystalline–amorphous interface elaborately changes the potential‐determining step to energetically favorable intermediates. As a result, Ni‐ZIF/NiB nanosheets supported on nickel foam (NF) require overpotentials of 67 mV for the hydrogen evolution reaction and 234 mV for the oxygen evolution reaction to achieve a current density of 10 mA cm−2. Remarkably, Ni‐ZIF/NiB@NF as a bifunctional electrocatalyst for overall water splitting enables an alkaline electrolyzer with 10 mA cm−2 at an ultralow cell voltage of 1.54 V. The present work may open a new avenue to the design of MOF‐derived composites for electrocatalysis.

Ultrathinning Nickel Sulfide with Modulated Electron Density for Efficient Water Splitting

“…[15][16][17][18] At present, noble Pt metal and Ir/Ru-based oxides are the benchmark electrocatalysts to speed up the HER and the OER, respectively. [19][20][21][22][23] Unfortunately, the tremella-like Ni 3 S 2 /MnS-O with abundant oxygen vacancies, which was favorable for HER and OER. [37] An in situ formation of {111} faceted Ni 3 S 2 on the surface of nickel foam toward HER and OER via a one-step hydrothermal process in a Na 2 S aqueous solution was also demonstrated.…”

Rational Design and Controlled Synthesis of V‐Doped Ni3S2/NixPy Heterostructured Nanosheets for the Hydrogen Evolution Reaction

“…It wasf ound through DFT that when Sw as replaced by P, the chemical stability and catalytic durability of the material were significantly enhanced. [47] NF has been widely used as ab ase materialf or energy storaged ue to itsh igh strength, toughness, and good electricalc onductivity,f or example, in HER, [48] supercapacitors, [49] and battery materials. [50] Due to its porous structure, nanomaterials borne on the NF could accelerate the contact of electrolyte and improvet he catalytic reaction.…”

Hierarchical Cu(OH)2@Co(OH)2 Nanotrees for Water Oxidation Electrolysis

“…The corresponding EIS results and their parameters errors are also displayed in Table S2. [28][29][30][31][32] The R ct of Cu (OH) 2 @Co(OH) 2 (4.6 Ω) is smaller than that of Cu(OH) 2 (9.7 Ω), suggesting the smaller charge-diffusion resistance of Cu (OH) 2 @Co(OH) 2 at the interface, and thus resulting in the faster charge diffusion kinetics and higher reaction rates. Combining with overpotential and Tafel results, it reveals that the OER activity of Cu(OH) 2 nanowires are remarkably improved by the electrodeposition of Co(OH) 2 nanoflakes.…”