Hierarchical Fe-Mn binary metal oxide core-shell nano-polyhedron as a bifunctional electrocatalyst for efficient water splitting

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 5; no. 46; pp. 17265 - 17274
• Main Authors: Li, Yun-Wu, Su, Shi-Kun, Yue, Cai-Zhen, Shu, Jun, Zhang, Peng-Fang, Du, Fang-Hui, Wang, Su-Na, Ma, Hui-Yan, Yin, Jie, Shao, Xin
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 30.11.2021
• Subjects: Clean energy; Electrocatalysts; Electrolysis; Iron oxides; Manganese; Metal oxides; Nanocomposites; Nanoparticles; Oxidation; Oxygen evolution reactions; Polyhedra; Redox reactions; Synergistic effect; Water splitting
• ISSN: 1477-9226; 1477-9234; 1477-9234
• DOI: 10.1039/d1dt03048e

Electrochemical water splitting is convinced as one of the most promising solutions to combat the energy crisis. The exploitation of efficient hydrogen and oxygen evolution reaction (HER/OER) bifunctional electrocatalysts is undoubtedly a vital spark yet challenging for imperative green sustainable energy. Herein, through introducing a simple pH regulated redox reaction into a tractable hydrothermal procedure, a hierarchical Fe 3 O 4 @MnO x binary metal oxide core-shell nano-polyhedron was designed by evolving MnO x wrapped Fe 3 O 4 . The MnO x effectively prevents the agglomeration and surface oxidation of Fe 3 O 4 nano-particles and increases the electrochemically active sites. Benefiting from the generous active sites and synergistic effects of Fe 3 O 4 and MnO x , the Fe 3 O 4 @MnO x -NF nanocomposite implements efficient HER/OER bifunctional electrocatalytic performance and overall water splitting. As a result, hierarchical Fe 3 O 4 @MnO x only requires a low HER/OER overpotential of 242/188 mV to deliver 10 mA cm −2 , a small Tafel slope of 116.4/77.6 mV dec −1 , combining a long-term cyclability of 5 h. Impressively, by applying Fe 3 O 4 @MnO x as an independent cathode and anode, the overall water splitting cell supplies a competitive voltage of 1.64 V to achieve 10 mA cm −2 and super long cyclability of 80 h. These results reveal that this material is a promising candidate for practical water electrolysis application. A hierarchical Fe 3 O 4 @MnO x binary metal oxide core-shell nano-polyhedron executes excellent HER/OER bifunctional electrocatalytic activities due to abundant active sites and the synergistic effects of each component.