16 / 42
Page 126
conferenceseries
.com
Volume 6
Research & Reviews: Journal of Material Sciences
ISSN: 2321-6212
Advanced Materials 2018
September 04-06, 2018
September 04-06, 2018 | Zürich, Switzerland
21
st
International Conference on
Advanced Materials & Nanotechnology
A composite of MnO
2
coated with graphene by galvanostatic electrodeposition and its highly active
and stable catalysis for oxygen reduction reaction
Xiaofeng Zhang, Zhongshui Li
and
Shen Lin
Fujian Normal University, China
T
he development of efficient, low-cost and stable electrocatalysts as the alternative to platinum for the oxygen reduction
reaction (ORR) plays key roles in several important energy storage and conversion technologies, such as fuel cells, metal-air
batteries [1]. Manganese oxides (MnOx) have been widely investigated as a promising non-precious catalyst for ORR because
of its abundance, low cost, environmental friendliness. Nevertheless, their practical applications of these materials are greatly
impeded by its lower energetic efficiencies which is primarily ascribed to their poor conductivity and relatively lower amount
of catalytically active sites. Moreover, MnOx catalysts are prone to aggregating in recycling use, which may further decrease
the ORR catalytic activity and stability [2]. Herein, a composite consisting of spherical MnO
2
coated with reduced graphene
oxide (MnO
2
@RGO) has been prepared by step galvanostatic electrodeposition (Figure 1). Firstly, MnO
2
is deposited on the
electrode surface by anodic galvanostatic method by the following process Mn
2+
+ 2H
2
O→MnOOH + e
-
+ 3H
+
→MnO
2
+ 4H
+
+
2e
-
. And then a three-dimensional composite of reduced graphene oxide (RGO) coating MnO
2
is obtained through cathodic
galvanostatic reduction of GO to RGO. The formed core-shell structure not only prevent graphene sheets from damage caused
by pressure of MnOx on the surface of graphene, which may thereby maximizing the catalyst conductivity extremely [3], but
also reduce the agglomeration of MnOx particles. In addition, owing to the larger specific surface area of graphene on the outer
layer and its stronger electron-donating ability than MnO
2
, the as-prepared composite is easier to adsorb and activate O
2
[4].
To the best of our knowledge, few research reports have been involved on the galvanostatic preparation of MnO
2
-graphene
core-shell composite and its application for ORR hitherto.
Figure 1
Schematic preparation and O
2
electroreduction of the MnO
2
@RGO catalyst.
Recent Publications
1. Debe MK (2012) Electrocatalyst approaches and challenges for automotive fuel cells. Nature 486: 43-51.
2. Lei K, Han X, Hu Y, Liu X, Cong L, Cheng F, Chen J (2015) Chemical etching of manganese oxides for electrocatalytic
oxygen reduction reaction. Chemical Communications 51: 11599-11602.
3. Sun M, Liu H, Liu Y, Qu J, Li J (2015) Graphene-based transition metal oxide nanocomposites for the oxygen reduction
reaction. Nanoscale 7: 1250-1269.
4. Wang C, Zhao Z, Li X, Yan R, Wang J, Li A, Duan X, Wang J, Liu Y, Wang J (2017) Three-Dimensional Framework of
Graphene Nanomeshes Shell/Co
3
O
4
Synthesized as Superior Bifunctional Electrocatalyst for Zinc–Air Batteries. ACS
Applied Materials & Interfaces 9: 41273-41283.
Biography
Xiaofeng Zhang graduated with PhD in chemistry from Fujian Normal University (P.R. China) in 2016. She is under the supervision of Prof. Shen Lin, majoring
in physical chemistry and materials chemistry. Her scientific interests focus on non-precious metal oxides/graphene composites and their catalytic properties of
oxygen reduction.
xfz_fz@163.comXiaofeng Zhang et al., Res. Rev. J Mat. Sci. 2018, Volume 6
DOI: 10.4172/2321-6212-C3-021