Iron-tuned super nickel phosphide microstructures with high activity for electrochemical overall water splitting. (April 2017)

• Record Type: Journal Article
• Authors: Huang, Huawei; Yu, Chang; Zhao, Changtai; Han, Xiaotong; Yang, Juan; Liu, Zhibin; Li, Shaofeng; Zhang, Mengdi; Qiu, Jieshan
• Is Part Of: Nano energy. Volume 34(2017:Apr.)
• Page Start: 472
• Page End: 480
• Publication Date: 2017-04
• Subjects: Water splitting -- Nickel-iron phosphide -- 2D carbon materials -- Oxygen evolution reaction -- Bifunctional electrocatalyst; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2017.03.016
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Large-scale hydrogen production by electrolytic splitting of water is mainly governed by high-efficient yet cheap electrocatalysts that could be capable of accelerating the sluggish hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report Fe-tuned Ni2 P electrocatalysts with controllable morphology and structure by regulating atomic ratio of Ni/Fe, and reveal the Fe species-modulated electronic state behaviors and -boosted catalytic activity for water splitting. The electrocatalytic activity of Fe-tuned Ni2 P nanosheets for both HER and OER can be further enhanced by assembling the nanosheets vertically on conductive 2D carbon fiber (CF) matrix to make hierarchical monolithic 3D electrode (Ni1.5 Fe0.5 P/CF), which features more accessible active sites and open structure that helps to speed up both the HER and OER. The improved electrocatalytic activity of Ni1.5 Fe0.5 P/CF is due to the combined synergistic effects of the high conductivity of CF matrix and the strong interaction between active species and the CF support, as evidenced by a low overpotential of 293 mV to achieve a high current density of 100 mA cm −2 with superior long-term stability for OER. When the monolithic 3D Ni1.5 Fe0.5 P/CF electrodes were used as both anode and cathode for overall water splitting, a current density of 10 mA cm −2 is generated at a low potential of 1.589 V, while at 20 mA cm −2, the potential is only 1.635 V. It has been demonstrated that modulating metal catalysts (nanosized nickel phosphide) with iron atoms is powerful, and may open up avenues to the design and fabrication of highly efficient catalysts for energy storage and conversion. Graphical abstract: A strategy for assembling iron-tuned nickel phosphides on 2D carbon fiber sheet to configure binder-free 3D Ni1.5 Fe0.5 P/CF as water splitting catalyst is presented, indicative of the iron species-triggered positive effects on structure and electrochemical activities. Interestingly, the as-made 3D Ni1.5 Fe0.5 P/CF can achieve up to 100 mA cm −2 only at overpotential of 293 mV for oxygen evolution, and can generate 10 mA cm −2 at a low potential of 1.589 V for overall water splitting. Highlights: A strategy for controllable regulation of Fe-doped Ni2 P is developed. Fe species can modulate the structure and boost catalytic activities of Ni2 P. The Ni1.5 Fe0.5 P nanosheets feature dual function for HER and OER. Ni1.5 Fe0.5 P/carbon fiber paper 3D electrodes deliver superior activity and stability for overall water splitting.