Nanocomposites Prepared by Ultrasonic

Spray Pyrolysis and their Applications

Rongbo Zheng

Southwest Forestry University, China

ICMAT 2011 DNANOFORMULATION 2011

1. Introduction

http://www.scs.uiuc.edu/suslick/suslickresearchdescription

•One step

•Rapidly

•Continuous

•Scalable

K. S. Suslick, J. Am. Chem. Soc., 2006, 128, 12642.

Porous Carbon

Precursor:

Alkali metal chloroacetate

or dichloroacetate

Magnetic luminescent mesostructured silica Microspheres

J. F. Wang, Adv. Funct. Mater., 2008,18, 2956.

2. Nanocomposites prepared by USP

USP

Different carbon precursor

Glucose

Citrate acid

Sodium citrate

Li-ion battery

ElectrophoreticDisplays

Schematic of the ultrasonic spray pyrolysis (USP) synthesis of nanocomposites

2.1 Rattle-type carbon hollow spheres and their application in Li-ion battery

� Definition: Rattle-type hollow spheres (denoted as A@B)

refer to hollow shells with a solid particle core and interstitial

hollow space in between.

� Conventional route to A@B

I Inside-to-outside routeII Outside-to-inside route

Sn@Carbon

SEM and TEM images of Sn@carbon obtained via USP of aqueous solutions containing SnCl4 and sodium citrate

R. B. Zheng, J. Phys. Chem. C, 2009, 113, 11065

Formation mechanism

SEM images of carbon hollow spheres obtained by USP of sodium citrate aqueous solutions

TEM images of Sn@carbon solids (A) collected withoutwater at 700 °C and (B) collected with water at 500 °C.

Illustration of the M@carbon obtained via USP of aqueous solutions containing metal salts and sodium citrate

(1): Sn NPs; capillary force; sodium citrate outer shell(2): Carbonization(3): Removing of water-soluble byproduct

Other M@Carbon by USP

20 30 40 50 60 70 80

B

311

22020

0

111

22011

1

200

Inte

nsity

(a.u

.)

2θ (degree)

A

XRD and TEM of (A) Pt@carbon and (B) Ag@Carbon obtained via USP of aqueous solutions containing metal salts and sodium citrate

The applications of Sn@C in Li-ion battery

0 20 40 60 80 1000

300

600

900

1200

1500 discharge charge

0.55mA/cm2

0.25mA/cm20.15mA/cm2

Cap

acity

(mA

h/g)

Cycle number

A

The cycling performance in the 0 mV-3 V (vs. Li+/Li) voltage window at different rate of Sn@carbon (46 wt % Sn).

2.2 Magnetic carbon hollow spheres

Reactant: aqueous solutions containing FeCl2 and citrate acid

Iron citrate

Citrate acid solution

(1) (2) (3)

Fe3O4 nanoparticles

Carbon

Formation mechanism

20 30 40 50 60 70 80

533

440

511

42240

0

311

Inte

nsity

(a.u

.)

2θ/degree

220

XRD patterns of Fe3O4-C magnetic hollow spheres obtained by USP of aqueous solutions containing FeCl2 and citrate acid.

Face-centered cubic Fe3O4

(JCPDS file No. 48–1487) or γγγγ-Fe2O3

0 200 400 600 800 100070

75

80

85

90

95

100

TG (%

)

Temperature (oC)

TGA of Fe3O4-C magnetic hollow spheres

•Increasing in mass between 180 and 280 °C

•Fe3O4 is oxidized to form Fe2O3

TEM images of Fe3O4-C magnetic hollow spheres obtained by USP of aqueous solutions containing FeCl2 and citrate acid

R. B. Zheng, Eur. J. Inorg. Chem., 2009, 20, 3003

TEM images of porous hollow carbon spheres obtained by acid treatment of Fe3O4-C magnetic hollow spheres in concentrated HCl (12 M) for 12 h.

Porous hollow carbon spheres

Acid-durability

-20000 -10000 0 10000 20000-40

-30

-20

-10

0

10

20

30

40

M (e

mu/

g)

H (Oe)

A

Ms: 35.9 emu/g

Mr: 2.1 emu/g

Hc: 34 Oe

(A) The M–H hysteresis loop and (B) TEM image of MCHMsafter acid treatment (pH = 1) at room temperature for 10 d.

Good dispersibility in various solvents

4000 3500 3000 2500 2000 1500 1000 500

Tran

smitt

ance

(a.u

.)

Wavenumber (cm-1)

O-H

C-H

C=C

Fe3O4

A

FTIR spectrum of sample HC 2; (B): photographs of sample HC 2 suspensions in methanol, ethanol and tetrachloroethylene.

2.3 Carbon–Iron Oxide Microspheres’Black Pigments and their application in Electrophoretic Displays

� Carbon black: density, 0.8 g/cm3

� Tetrachloroethylene:density, 1.6 g/cm3

B. Comiskey, et al., Nature, 1998, 394, 253

�����

�������GlucoseFeCl2

USP

Doping-eroding route

4000 3000 2000 1000 0

Fe2O

3

Tran

smitt

ance

(a.u

.)

�Wavemumber (cm-1)

O-H

C-H C=C Fe3O

4

FT-IR spectrum of carbon-iron oxide

2.2 g/cm3, 1.7 g/cm3, 1.5 g/cm3

Carbon-iron oxide with (from left to right 0, 1, 12 h) etching time aredispersed in tetrachloroethylene.

X. W. Meng, R.B. Zheng, et al, Nanoscale Res Lett 2010, 5,1664.

Black-white e-paper

2.4 Silver porous hollow spheres

GlucoseAgNO3

USP

SEM of SPHS prepared via USP of aqueous solutions containing glucose and AgNO3

Glucose worked as reducing agent and pore-forming directing agent

R.B. Zheng, Applied surface sci., 2011, 257, 2367

Vis-NIR spectrum of SPHS (A) and silver solid spheres (B) fabricated via USP.

400 600 800 1000 1200

Abs

optio

n (a

.u.)

Wavelength (nm)

A

B

480 nm

Thanks for your attention!!!