Constructing Conductive Interfaces between Nickel Oxide Nanocrystals and Polymer Carbon Nitride for Efficient Electrocatalytic Oxygen Evolution Reaction

Abstract

Combining transition metal oxide catalysts with conductive carbonaceous material is a feasible way to improve the conductivity. However, the electrocatalytic performance is usually not distinctly improved because the interfacial resistance between metal oxides and carbon is still large and thereby hinders the charge transport in catalysis. Herein, the conductive interface between poorly conductive NiO nanoparticles and semi-conductive carbon nitride (CN) is constructed. The NiO/CN exhibits much-enhanced oxygen evolution reaction (OER) performance than corresponding NiO and CN in electrolytes of KOH solution and phosphate buffer saline, which is also remarkably superior over NiO/C, commercial RuO 2 , and mostly reported NiO-based catalysts. X-ray photoelectron spectroscopy and extended X-ray absorption fine structure spectrum reveal that a metallic Ni-N bond is formed between NiO and CN. Density functional theory calculations suggest that NiO and CN linked by a Ni-N bond possess a low Gibbs energy for OER intermediate adsorptions, which not only improves the transfer of charge but also promotes the transmission of mass in OER. The metal-nitrogen bonded conductive and highly active interface pervasively exists between CN and other transition metal oxides including Co 3 O 4 , CuO, and Fe 2 O 3 , making it promising as an inexpensive catalyst for efficient water splitting.

Non‐Noble‐Metal‐Based Electrocatalysts toward the Oxygen Evolution Reaction

“…As such, the CoO x NPs/BNG electrocatalyst shows a low overpotential of 295 mV at 10 mA cm –2 for the OER (Figure 3B). Liao et al fabricated a nickel oxide (NiO) and carbon nitride hybrid nanocomposite through bridging the poorly conductive metal oxide and the semiconductive carbonaceous material via forming NiN bonds 26. The facilitated charge transport in catalysis boosts the electrocatalytic performance for the OER as shown in Figure 3C (overpotential of 261 mV at 10 mA cm –2 ).…”

“…C) OER polarization curves of different catalysts in 1.0 m KOH electrolyte. Reproduced with permission 26. Copyright 2019, Wiley‐VCH.…”

“…For this reason, we put primary focus on these non‐noble‐metal‐based electrocatalysts in this review. To overcome the high overpotential of the OER, numerous non‐noble‐metal‐based electrocatalysts have been developed, including metals/alloys,23,24 oxides,25–31 hydroxides,32–37 chalcogenides,38–42 phosphides,5,43,44 phosphates/borates,19,45,46 borides,47 nitrites,48,49 and other compounds 50,51…”

Periodic Porous 3D Electrodes Mitigate Gas Bubble Traffic during Alkaline Water Electrolysis at High Current Densities

“…Bubble release efficiency is improved by increasing the pore size to 750 µm. For OER, since fewer gas bubbles are generated compared to HER at the same current, the performance of electrodes with larger pore sizes (NF, 450 and 750 µm [27] NiO x @bamboo-like carbon nanotubes-NF (5 mV s −1 ), [28] NiCo 2 S 4 /NF (2 mV s −1 ), [29] MoO x /Ni 3 S 2 -NF (0.1 mV s −1 ), [6a] FeO x /Fe foam (0.1 mV s −1 ); [30] and (e) OER catalysts, including NiO/carbon nitride (10 mV s −1 ), [31] FeO x /Fe foam (0.1 mV s −1 ), [30] NiFeP (20 mV s −1 ), [32] MoO x /Ni 3 S 2 -NF (0.1 mV s −1 ), [6a] and Ni-Fe-OH@Ni 3 S 2 /NF (0.5 mV s −1 ) [33] samples) is less dependent on the bubbles. However, when the pore size is decreased to 150 µm, the performance becomes more dependent on the bubble transport behavior ( Figure S12d, Supporting Information).…”

Nickel-Embedded Carbon Materials Derived from Wheat Flour for Li-Ion Storage

“…As for the prepared NC-600 and NC-800, three sharp diffraction peaks at 2θ = 44.5, 51.8, and 76.4° are observed, which could be assigned to the lattice planes of (111), (200), and (220) for nickel metal with (Fm-3m) space group (JCPDS card 65-2865), respectively [ 36 , 37 , 38 , 39 ]. The metallic nickel is formed via a reduction reaction of Ni (NO 3 ) 2 by the surrounding carbon atoms under high carbonization temperature [ 40 , 41 ]. It is well-known that the crystalline structure of the carbon anode materials, for example, the (002) lattice plane, significantly influences the intercalation/de-intercalation of Li + .…”