Faceted Colloidal Metallic Ni₃N Nanocrystals: Size-Controlled Solution-Phase Synthesis and Electrochemical Overall Water Splitting

Abstract

We report a size-tunable synthesis of faceted Ni3N nanocrystals (NCs) at low temperatures (210–230 °C) via a solution processing route for the first time and demonstrate their viability as an efficient electrocatalytic material for overall water splitting. The high carrier density of Ni3N NCs combined with the faceted morphology is shown to render a broadband absorption in the infrared range attributed to the energy-dispersed localized surface plasmon excitation. The Ni3N NCs show an efficient electrocatalytic activity with impressively low overpotentials of ∼74 and 142 mV for the hydrogen evolution reaction (HER) and 190 and 270 mV for the oxygen evolution reaction (OER), with current densities of 10 and 100 mA/cm2, respectively. The Tafel slopes for HER and OER are 49 and 56 mV/dec, respectively, which are quite small. Furthermore, these Ni3N NCs require a small voltage of 1.48 V to produce a current density of 10 mA/cm2 for overall water splitting conducted in an alkaline electrolyzer when they are used both as a cathode and an anode.

Precursor chemistry of metal nitride nanocrystals

“…95,96 The early chemical synthetic methods to obtain Ni 3 N were based on the decomposition of nickel complexes at high temperatures and in presence of ammonia or hydrazine. 90,92 Recently a one-step synthesis of colloidally stable Ni 3 N NCs has been reported by Shanker et al 97 Nickel acetate is used as precursor and OLAm is chosen as ligand. Different nanocrystal sizes are obtained (5 to 80 nm) by varying the time and temperature in a narrow window, see Fig.…”

“…Recently a one-step synthesis of colloidally stable Ni 3 N NCs has been reported by Shanker et al 97 Nickel acetate is used as precursor and OLAm is chosen as ligand. Different nanocrystal sizes are obtained (5 to 80 nm) by varying the time and temperature in a narrow window, see Fig.…”

NaCl-Assisted Ultrasmall Mo2C Nanocrystals Confined in N, S Double-Doped Hierarchical Porous Carbon for Efficient Hydrogen Generation

“…Hydrogen energy is a source of green, efficient, and sustainable secondary energy source and has advantages such as high energy density, renewable energy, zero pollution, and zero carbon emissions . As one of the effective means of hydrogen generation, electrocatalytic water splitting has attracted the attention of many researchers . Due to its high efficiency, precious Pt-, Pd-, Ru-, and Rh-based catalysts have exhibited great efficiency in water splitting .…”

“…1 As one of the effective means of hydrogen generation, electrocatalytic water splitting has attracted the attention of many researchers. 2 Due to its high efficiency, precious Pt-, Pd-, Ru-, and Rh-based catalysts have exhibited great efficiency in water splitting. 3 However, because of their high price and low earth abundance, noble metal-based catalysts are difficult use in large-scale industries.…”

A multidentate polymer microreactor route for green mass fabrication of mesoporous NaYF4 clusters

“…15 Although conceptually elegant, we find it difficult to extend the LLP method or ''ligand stripping'' method to water soluble clusters larger than 100 nm. 16,17 Herein we demonstrate a ''multidentate polymer microreactor'' method that enables the precisely controlled aggregation of nanocrystals and produces a series of complex 3D nanostructures with well-defined morphologies. Using NaYF 4 as an example, we demonstrate that the use of PAAS as the ''multidentate polymer microreactor'' allows the controllable growth of primary NaYF 4 nanocrystallites and induces aggregation of nanocrystals into well-defined clusters.…”