Nitrogen-doped graphene derived from ionic liquid as metal-free catalyst for oxygen reduction reaction and its mechanisms

She, Yiyi1,3; Chen, Jinfan2; Zhang, Chengxu1,4; Lu, Zhouguang5; Ni, Meng6; Sit, Patrick H. -L.2; Leung, Michael K. H.1,2,3

2018-09

10.1016/j.apenergy.2018.05.015

APPLIED ENERGY   影响因子和分区

0306-2619

1872-9118

It is of great significance to develop N-doped carbon materials possessing high catalytic activity, excellent durability and low cost for oxygen reduction reaction (ORR) due to imperative for energy devices with high energy density, such as fuel cells and metal-air batteries. Herein, N-doped graphene is prepared by annealing a homogeneous mixture of graphene oxide (GO) and ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) in N-2 atmosphere. By entrapping effect, the ionic liquid serves as both N source and restacking protectant in formation of high-quality N-doped graphene sheets. Electrochemical characterizations reveal that the obtained N-doped graphene possesses excellent electrocatalytic properties for ORR in alkaline condition with onset potential of -39 mV (vs. Hg/HgO) and current density of 5.83 mA cm(-2) at -0.9 V (vs. Hg/ HgO) at 2500 rpm. The microstructure of the prepared catalysts and their ORR catalytic activities are highly sensitive to calcination temperature and the optimal temperature is 900 degrees C. Density functional theory (DFT) analysis indicates from the atomic point of view that N atoms with different configurations contribute unequally to the ORR performance enhancement. Pyridinic N at the edge of graphene plays the most significant role in improving ORR performance owing to the largest number of active sites and lower band gap. Based on the experimental and simulation results, the beneficial properties of the as-prepared N-doped graphene for ORR are ascribed to the superior conductivity of graphene, the high N doping content and the high proportion of active pyridinic N species.

Density functional theory Fuel cell Heteroatom doping Metal-air battery Metal-free catalyst

SCI ; CPCI-S ; EI

英语

其他

CityU SRG Fund[7004166]

Energy & Fuels ; Engineering

Energy & Fuels ; Engineering, Chemical

WOS:000438181000038

ELSEVIER SCI LTD

20182105220325

Catalyst activity ; Doping (additives) ; Electrolytic reduction ; Energy gap ; Fuel cells ; Graphene ; Ionic liquids ; Metals ; Nitrogen ; Oxygen ; Secondary batteries

Ore Treatment:533.1 ; Fuel Cells:702.2 ; Chemical Products Generally:804 ; Probability Theory:922.1

ENGINEERING

Web of Science

1.City Univ Hong Kong, Sch Energy & Environm, Abil R&D Energy Res Ctr, Hong Kong, Hong Kong, Peoples R China
2.City Univ Hong Kong, Sch Energy & Environm, Hong Kong, Hong Kong, Peoples R China
3.City Univ Hong Kong, Shenzhen Res Inst, Shenzhen, Guangdong, Peoples R China
4.Kunming Univ Sci & Technol, Fac Met & Energy Engn, Engn Lab Adv Battery & Mat Yunnan Prov, Kunming, Yunnan, Peoples R China
5.South Univ Sci & Technol China, Dept Mat Sci & Engn, Shenzhen 518055, Guangdong, Peoples R China
6.Hong Kong Polytech Univ, Dept Bldg & Real Estate, Hong Kong, Hong Kong, Peoples R China

She, Yiyi,Chen, Jinfan,Zhang, Chengxu,et al. Nitrogen-doped graphene derived from ionic liquid as metal-free catalyst for oxygen reduction reaction and its mechanisms[J]. APPLIED ENERGY,2018,225:513-521.

She, Yiyi.,Chen, Jinfan.,Zhang, Chengxu.,Lu, Zhouguang.,Ni, Meng.,...&Leung, Michael K. H..(2018).Nitrogen-doped graphene derived from ionic liquid as metal-free catalyst for oxygen reduction reaction and its mechanisms.APPLIED ENERGY,225,513-521.

She, Yiyi,et al."Nitrogen-doped graphene derived from ionic liquid as metal-free catalyst for oxygen reduction reaction and its mechanisms".APPLIED ENERGY 225(2018):513-521.