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Cation-tunable flower-like (NixFe1−x)2P@graphitized carbon films as ultra-stable electrocatalysts for overall water splitting in alkaline media.
- Source :
- Journal of Materials Chemistry A; 9/21/2019, Vol. 7 Issue 35, p20357-20368, 12p
- Publication Year :
- 2019
-
Abstract
- Electrocatalytic water splitting is a promising strategy for green and renewable energy development by transforming electrical energy into hydrogen energy. Herein, we report a series of flower-like electrocatalysts with cation-tunable (Ni<subscript>x</subscript>Fe<subscript>1−x</subscript>)<subscript>2</subscript>P nanoparticles encapsulated by porous graphitized carbon films (GCs) via the combination of morphology control and component adjustment. By progressively tailoring the atomic ratios of Ni/Fe, the electronic structure and electrocatalytic activities of (Ni<subscript>x</subscript>Fe<subscript>1−x</subscript>)<subscript>2</subscript>P can be intriguingly modified to achieve versatile catalytic behavior for both the HER and the OER. DFT calculations also validate that the (Ni<subscript>x</subscript>Fe<subscript>1−x</subscript>)<subscript>2</subscript>P with an optimal atomic ratio of Ni/Fe can support the ‖ΔG<subscript>H*</subscript>‖ to be close to the optimum and decrease the adsorption energy for water, which can boost the water splitting. Meanwhile, anchoring the adjustable (Ni<subscript>x</subscript>Fe<subscript>1−x</subscript>)<subscript>2</subscript>P nanoparticles into GC interlayers can endow these composites with more available active sites, excellent conductivity and enhanced stability. In fact, the combined synergistic effect of cation-tuned (Ni<subscript>x</subscript>Fe<subscript>1−x</subscript>)<subscript>2</subscript>P nanoparticles and porous conductive GCs is the reason that these composites exhibit enhanced electrocatalytic activities, as illustrated by a low overpotential of 206 mV at j = 10 mA cm<superscript>−2</superscript> (256 mV at j = 50 mA cm<superscript>−2</superscript>) for the OER. Meanwhile, the bifunctional (Ni<subscript>0.75</subscript>Fe<subscript>0.25</subscript>)<subscript>2</subscript>P@GCs, as both the cathode and anode of an electrolyzer, effectuates an ultra-small cell potential of 1.541 V at j = 10 mA cm<superscript>−2</superscript> (1.573 V at j = 20 mA cm<superscript>−2</superscript>) for 30 h during electrolysis of water, rivaling commercial IrO<subscript>2</subscript> and Pt/C catalysts. More importantly, this work can provide a way of fabricating cost-saving, component-tunable and high-efficiency bimetallic electrocatalysts for water splitting. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 20507488
- Volume :
- 7
- Issue :
- 35
- Database :
- Complementary Index
- Journal :
- Journal of Materials Chemistry A
- Publication Type :
- Academic Journal
- Accession number :
- 138541935
- Full Text :
- https://doi.org/10.1039/c9ta07762f