N-doped carbon coated FeNiP nanoparticles based hollow microboxes for overall water splitting in alkaline medium

• Published in: International journal of hydrogen energy 2018-12, Vol.43 (49), p.22226-22234
• Main Authors: Du, Yunmei, Han, Yi, Huai, Xudong, Liu, Yanru, Wu, Caiyun, Yang, Yu, Wang, Lei
• Format: Article
• Language: English
• Subjects: Electrocatalysts; Hydrogen evolution reaction; Iron nickel phosphide; N-doped carbon; Nanoparticle; Oxygen evolution reaction
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2018.10.091

Stable, earth-abundant and efficient electrocatalysts for overall water splitting are urgently needed. In this work, we have reported the synthesis of FeNiP/NC hollow microboxes (FeNiP/NC) based bifunctional electrocatalyst via the phosphorization process using rationally designed cube-type metal-organic framework (FeNi-MOF) as both the template and carbon source. The FeNiP/NC, which were obtained by assembling the uniform FeNiP nanoparticals together through N-doped carbon, manifests outstanding catalytic performances for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in KOH solution. Notably, FeNiP/NC displays exceptional activity when it was utilized as both anode and cathode toward overall water splitting with potential of 1.54 V at a current density of 10 mA cm−2 in alkaline electrolyte, which is much better than FeP/NC and Ni2P/NC electrocatalyst. More importantly, the improvement of the catalytic activities of FeNiP/NC mainly benefits from the well dispersion of FeNiP nanoparticles on the surface of carbon support, the large active surface area and the doping of N and C derived from organic ligands. In addition, the enhanced electrocatalytic performance of FeNiP/NC for OER is closely related with the in-situ formed surficial MOOH (M = Fe, Ni) active sites, which has been confirmed by X-ray photoelectron spectroscopy (XPS) analysis. [Display omitted] •Uniform FeNiP nanoparticles assembled together through N-doped carbon based hollow microboxs have been synthesized.•FeNiP/NC was obtained using FeNi-MOF as precursor.•Hollow FeNiP/NC is a bifunctional electrocatalyst for HER and OER in alkaline media.•The MOOH (M = Fe, Ni) with high activity for OER have in-situ formed on the surface of FeNiP/NC.