Artificial Heterointerfaces Achieve Delicate Reaction Kinetics towards Hydrogen Evolution and Hydrazine Oxidation Catalysis

Abstract

Electrochemical water splitting for H2 production is limited by the sluggish anode oxygen evolution reaction (OER), thus using hydrazine oxidation reaction (HzOR) to replace OER has received great attention. Here we report the hierarchical porous nanosheet arrays with abundant Ni3N‐Co3N heterointerfaces on Ni foam with superior hydrogen evolution reaction (HER) and HzOR activity, realizing working potentials of −43 and −88 mV for 10 mA cm−2, respectively, and achieving an industry‐level 1000 mA cm−2 at 200 mV for HzOR. The two‐electrode overall hydrazine splitting (OHzS) electrolyzer requires the cell voltages of 0.071 and 0.76 V for 10 and 400 mA cm−2, respectively. The H2 production powered by a direct hydrazine fuel cell (DHzFC) and a commercial solar cell are investigated to inspire future practical applications. DFT calculations decipher that heterointerfaces simultaneously optimize the hydrogen adsorption free energy (ΔGH*) and promote the hydrazine dehydrogenation kinetics. This work provides a rationale for advanced bifunctional electrocatalysts, and propels the practical energy‐saving H2 generation techniques.

Three-Phase Heterojunction NiMo-Based Nano-Needle for Water Splitting at Industrial Alkaline Condition

“…7f, g and S49). The volume-time curve for H 2 and O 2 is obtained by water drainage method at 0, 10,15,20,25,30,35,40,45, and 50 min measured at 30.0 mA. The volume-time curve for H 2 and O 2 is about 2:1, and they are close to the theoretical values, indicating the nearly 100% Faradic efficiency.…”

“…4 c, d), which can realize the redistribution of electrons at the interface for further optimizing the adsorption energy of H- and O-containing intermediates to boost the HER/OER intrinsic activity [ 25 ]. Additionally, heterojunction can enhance the electron transfer ability to improve the WS performance at large current density [ 45 ]. The high-angle annular dark-field scanning TEM (HAADF-STEM) and elemental mapping images sugggest the uniform distribution of C, N, O, Ni, and Mo on the Ni/MoO 2 @CN (Fig.…”

3D Porous Honeycomb‐Like CoN‐Ni3N/N‐C Nanosheets Integrated Electrode for High‐Energy‐Density Flexible Supercapacitor

“…[ 29,30 ] Meanwhile, the two spin‐orbit twosomes at 782.1 and 797.5 eV were attributed to the signals of Co‐O, which may be due to the unavoidably oxidation when the sample exposed to the air. [ 31 ] Likewise, the high‐resolution Ni 2p spectra in Figure 3d could also be deconvoluted into two categories of peaks, assigning to the Ni‐N(856.4 and 873.9 eV) and Ni‐O (854.5 and 872.1 eV), respectively. Besides, the two major peaks at 397.8 and 398.7 eV in the spectrum of N1s (Figure 3e) were assigned to the chemical bonds of Co‐N and Ni‐N, which further confirmed the formation of nitride materials.…”

Construction of Nickel‐Based Dual Heterointerfaces towards Accelerated Alkaline Hydrogen Evolution via Boosting Multi‐Step Elementary Reaction

“…The content of Ni 2+ in the material increased after the reaction, indicating that the surface of the material was partially oxidized during the reaction, which is also common for Ni‐based materials as revealed in previous reports. [ 6c,14b,23 ] Moreover, the formation of the Ni 2+ (such as Ni(OH) 2 ) on the surface was conducive to the dissociation of water molecules, thus can maintain or even promote the performance of the material. [ 24 ] Subsequently, to evaluate the efficiency of the HER in this system, the Faraday efficiency was performed and the gas was collected by gas chromatography.…”