Porous Flower‐Like Nanoarchitectures Derived from Nickel Phosphide Nanocrystals Anchored on Amorphous Vanadium Phosphate Nanosheet Nanohybrids for Superior Overall Water Splitting

Abstract

Transition metal phosphides (TMPs) and phosphates (TM‐Pis) nanostructures are promising functional materials for energy storage and conversion. Nonetheless, controllable synthesis of crystalline/amorphous heterogeneous TMPs/TM‐Pis nanohybrids or related nanoarchitectures remains challenging, and their electrocatalytic applications toward overall water splitting (OWS) are not fully explored. Herein, the Ni2P nanocrystals anchored on amorphous V‐Pi nanosheet based porous flower‐like nanohybrid architectures that are self‐supported on carbon cloth (CC) substrate (Ni2P/V‐Pi/CC) are fabricated by conformal oxidation and phosphorization of pre‐synthesized NiV‐LDH/CC. Due to the unique microstructures and strong synergistic effects of crystalline Ni2P and amorphous V‐Pi components, the obtained Ni2P/V‐Pi/CC owns abundant active sites, suitable surface/interface electronic structure and optimized adsorption‐desorption of reaction intermediates, resulting in outstanding electrocatalytic performances toward hydrogen and oxygen evolution reactions in alkaline media. Correspondingly, the assembled Ni2P/V‐Pi/CC||Ni2P/V‐Pi/CC electrolyzer only needs an ultralow cell voltage (1.44 V) to deliver 10 mA cm−2 water‐splitting currents, exceeding its counterparts, recently reported bifunctional catalysts‐based devices, and Pt/C/CC||IrO2/CC pairs. Moreover, the Ni2P/V‐Pi/CC||Ni2P/V‐Pi/CC manifests remarkable stability. Also, such device shows a certain prospect for OWS in acidic media. This work may spur the development of TMPs/TMPis‐based nanohybrid architectures by combining structure and phase engineering, and push their applications in OWS or other clean energy options.

Advancing the Development of Hollow Micro/nanostructured Materials for Electrocatalytic Water Splitting: Current State, Challenges, and Perspectives

“…. Low ΔG H* (−0.23 eV) for WC(100)−W 2 C(120) was observed in comparison to WC(100) and WC(100)−W 2 C(120). The study shows that the heterointerface could reduce W−H bond strength and optimize ΔG(H*), leading to faster H ads and desorption on active centers of the W atom and increased HER performance.…”

“…Figure4dfurther reveals the Gibbs free energy profile of water adsorption and dissociation on electrocatalysts.The WC(100)−W 2 C(120) showed a water molecule dissociation barrier of 0.21 eV, substantially lower compared to that of WC(100) (0.48 eV) and WC (0.63 eV) 85. Theoretical calculations show that the heterointerface allows slow water adsorption and dissociation to accelerate hydrogen intermediate generation, promoting HER in basic/neutral conditions.…”