1. Nitrogen-enriched carbon nanofibers containing Cu-loaded porous carbon beads for the abatement of NO emissions
Bhaskar Bhaduri1 and Nishith Verma1,2
1 Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur (India)
2 Center for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur (India)
Experimental Set-up
SEM and EDX
Introduction
Various stationary and mobile sources such as thermal power plants, nitric acid plants, and automobiles emit significant amounts of nitric oxide (NO), responsible for several environmental hazards such as acid rain, photochemical smog, and the depletion of ozone layer.
Among several methods used for the abatement of NO emissions, selective catalytic reduction (SCR) has been extensively studied using ammonia, urea, and hydrocarbon gases as the reducing agents.
A wide variety of catalysts containing noble metals, transition metal oxides, and zeolites modified with metals have been used for the SCR of NO.
Schematic illustration of the experimental set-up used for catalyst activity test
SEM images of (a) CBs, (b) Cu-CBs and (c) Cu-CNFs/CBs, (d) EDX spectra of Fig. c
SEM images of (a-a/) N-Cu-CNFs/CBs, (b-b/) NO exposed N-Cu-CNFs/CBs. Fig. c shows the EDX spectra of NO exposed N-Cu-CNFs/CBs.
Characterization Techniques
XPS and Raman analysis
The prepared materials were characterized using several analytical and spectroscopic techniques such as atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), temperature programmed reduction (TPR) and so on.
Objective
Results and Discussion
Catalytic activity studies
Synthesis of N-enriched Cu nanoparticles grown carbon nanofibers (CNFs) containing porous carbon beads (CBs) for the removal of NO emissions by reduction.
Reaction Conditions:
TPR analysis
(W = 0.5 g, CNO = 400
ppm, reaction time =
5 h)
Optimum reduction temperature
for the reduction of CuxOy -CBs
is 270 oC
Schematic for Material Preparation
Interaction of NO molecules with the catalyst
Cu NPs
CBs
CNF
N+ e-
+2 NO
+ Heat -
Hyponitrite species N2
XRD Pattern
Scherrer Equation:
r (nm) = Kλ/βCosθ
Avg. Cu crystallite
size rages from 19-
37 nm
Conclusions
Cu NPs-doped porous activated carbon beads (~0.8 mm) decorated with CNFs were synthesized.
The Cu NPs in situ incorporated into the PVA polymeric matrix during the synthesis step acted as the CVD catalyst for growing the CNFs.
The high catalytic activity of the material was attributed to the combined roles of the catalytic Cu NPs, reactive CNFs, large N-contents of the material, and the porous activated carbon bead.
AAS measurements to evaluate Cu loadings of the prepared materials
Materials
loadings (mg/g)
PhB -
Cu_PhB
3.4
CuxOy-CB
20.0
Cu-CNF/CB
14.0
Textural properties of the prepared materials
Sample
SBET (m2/g)
VT (cm3/g)
PSD (%)
Micro
Meso
Macro
PhB
Cu-PhB
1.97
0.50
0.001
CB (without pre- oxidation)
998
0.531
88.17
5.24
6.59
CB (with pre-oxidation)
1748
0.918
78.48
8.26
13.26
CuxOy-CB
Cu-CB
1056
1172
0.568
0.615
75.82
72.40
9.28
12.19
14.90
15.41
Cu-CNF/CB
733
0.462
70.12
15.88
14.00
N-Cu-CNF/CB
648
0.411
69.51
12.23
18.26
References
B. Bhaduri, N. Verma. Preparation of asymmetrically distributed bimetal CeO2 and Cu NPs in nitrogen-doped ACF/CNF for the removal of NO by reduction. Journal of Colloid and Interface Science 436 (2014)