Α-MnO2 Nanowires/Graphene Composites with High Electrocatalytic Activity for Mg-Air Fuel Cell. (20th November 2016)

• Record Type: Journal Article
• Authors: Jiang, Min; He, Hao; Huang, Chen; Liu, Bo; Yi, Wen-Jun; Chao, Zi-Sheng
• Is Part Of: Electrochimica acta. Volume 219(2016)
• Page Start: 492
• Page End: 501
• Publication Date: 2016-11-20
• Subjects: α-MnO2 -- Graphene -- Nanowires -- ORR -- Mg-air fuel cell; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.09.004
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Highlights: α-MnO2 NWs/graphene was synthesized and studied in Mg-air fuel cell. The performance of α-MnO2 NWs/graphene is close to the Pt/C. The ORR mechanism involves a one-step, quasi-4-electron pathway. A large area (5 cm*5 cm) cathode was prepared and tested in a full cell. Abstract: This paper reports the preparation of α-MnO2 NWs/graphene composites as the cathode catalyst for magnesium-air fuel cell and its excellent electrochemistry performance. The composites are synthesized by self-assembly of α-MnO2 nan α-MnO2 NWs/graphene was synthesized and studied in Mg-air fuel cell. α-MnO2 NWs/graphene was synthesized and studied in Mg-air fuel cell. owires (NWs) on the surface of graphene via a simple hydrothermal method. The α-MnO2 NWs/graphene composites showed a higher electrochemical activity than the commercial MnO2 . The oxygen reduction peak of the α-MnO2 NWs/graphene composites catalyst is tested in a 0.1 M KOH solution at −0.252 V, which is more positive than the commercial MnO2 (−0.287 V). The ORR limit current density for 28% α-MnO2 NWs/graphene composite is approximately 2.74 mA/cm 2, which is similar to that of the 20% Pt/C(2.79 mA/cm 2 ) in the same conditions. Based on the Koutecky–Levich plot, the ORR mechanism of the composite involves a one-step, quasi-4-electron pathway. In addition, magnesium-air fuel cell with α-MnO2 NWs/graphene as catalyst possesses higher current density (140 mA/cm 2 ) and power density (96 mW/cm 2 ) compared to the commercial MnO2 . This study proves that the cost-effective α-MnO2 NWs/graphene with higher power generation ability make it possible for the substitute of the noble metals catalyst in the Mg-air fuel cell.