Cr‐Doped FeNi–P Nanoparticles Encapsulated into N‐Doped Carbon Nanotube as a Robust Bifunctional Catalyst for Efficient Overall Water Splitting

• Published in: Advanced materials (Weinheim) Vol. 31; no. 15; pp. e1900178 - n/a
• Main Authors: Wu, Yiqiang, Tao, Xu, Qing, Yan, Xu, Han, Yang, Fan, Luo, Sha, Tian, Cuihua, Liu, Ming, Lu, Xihong
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.04.2019
• Subjects: bifunctional catalyst; Carbon nanotubes; Catalysis; Catalysts; Charge transfer; Cr doping; Current density; Density functional theory; Doping; Electrocatalysts; Encapsulation; Hydrogen evolution reactions; Nanoparticles; Oxygen evolution reactions; structural manipulation; transition metals phosphide; Water splitting; transition metals phosphide; bifunctional catalyst; water splitting; Cr doping; structural manipulation
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201900178

Exploring high‐efficiency, stable, and cost‐effective bifunctional electrocatalysts for overall water splitting is greatly desirable and challenging. Herein, a newly designed hybrid catalyst with Cr‐doped FeNi–P nanoparticles encapsulated into N‐doped carbon nanotubes (Cr‐doped FeNi–P/NCN) with unprecedented electrocatalytic activity is developed by a simple one‐step heating treatment. The as‐synthesized Cr‐doped FeNi–P/NCN with moderate Cr doping exhibits admirable oxygen evolution reaction and hydrogen evolution reaction activities with overpotentials of 240 and 190 mV to reach a current density of 10 mA cm−2 in 1 m KOH solution. When used in overall water splitting as a bifunctional catalyst, it needs only 1.50 V to give a current density of 10 mA cm−2, which is superior to its typically integrated Pt/C and RuO2 counterparts (1.54 V @ 10 mA cm−2). Density functional theory calculation confirms that Cr doping into a FeNi‐host can effectively alter the relative Gibbs adsorption energy and reduces the theoretical overpotential. Additionally, the synergetic effects between Cr‐doped FeNi–P nanoparticles and NCNs are regarded as significant contributors to accelerate charge transfer and promote electrocatalytic activity in hybrid catalysts. A facile but versatile strategy is demonstrated to prepare Cr‐doped FeNi–P nanoparticles encapsulated in N‐doped carbon nanotube as a robust electrocatalyst for water splitting. The obtained catalyst exhibits admirable HER/OER activity and favorable stability. More importantly, it needs a desirably low voltage around 1.50 V to reach 10 mA cm−2 when integrated for overall water splitting as bifunctional catalysts.