Effect of RVC porosity on the performance of PbO2 composite coatings with titanate nanotubes for the electrochemical oxidation of azo dyes
Effect of RVC porosity on the performance of PbO2 composite coatings with titanate nanotubes for the electrochemical oxidation of azo dyes
Reticulated vitreous carbon (RVC) of different porosities (20, 45, 60, 80, and 100 ppi—pores per inch) has been used as a large surface area substrate for preparing 3D-like PbO2 coatings (RVC/PbO2) as well as composite coatings with hydrothermally synthesized titanate nanotubes (RVC/PbO2/TiNT) by galvanostatic electrodeposition from baths containing lead(II) methanesulfonate and methanesulfonic acid. The effect of the RVC porosity on the coating thickness, the electrocatalytic behaviour and the ability to remove the colour and total organic carbon (TOC) from solutions containing the azo dye Methyl Orange has been systematically assessed. As shown from scanning electron micrographs, the greatest thickness (up to 120 ?m) was obtained using > 60 ppi, but the ?-PbO2 nanocrystallytes mainly grew on the external surface, leaving mostly uncoated inner RVC stripes and ending in planar-like PbO2-based electrodes. In contrast, thinner but perfectly adherent and homogeneous coating of the inner and outer surface was achieved with 20-60 ppi, showing electrodes with an optimal three-dimensionallity. This was especially confirmed by cyclic voltammograms for the composite coatings, as deduced from their highest electroactivity that can be related to enhanced adsorption onto the TiNT clusters and the larger ability to produce active PbO2(radical dotOHOH). The comparative electro-oxidation of 0.25 × 10?3 mol dm?3 Methyl Orange acidic solutions in 0.05 mol dm?3 Na2SO4 at 0.6 A demonstrated that RVC (45 ppi)/PbO2/TiNT was the optimum material. It allowed the quickest decolourisation, reaching 60% in 2.5 min and > 98% at 45 min, and > 55% TOC abatement at 240 min. The anode presented a perfect surface coverage, with no evidence of RVC degradation. The effect of dye concentration and supporting electrolyte nature was studied, revealing a very positive effect of NaCl.
9-17
Ramírez, G.
8d31524f-613d-40a8-9386-fae3cc77747c
Recio, F.J.
c1569d6a-c8ca-4987-8313-01ef4c6cf776
Herrasti, P.
9ec58bb1-128c-4204-853f-804a91926275
Ponce De Leon Albarran, C.
508a312e-75ff-4bcb-9151-dacc424d755c
Sirés, I.
85e095d9-c3fa-48e2-aff3-65f0f4b2e4b4
20 June 2016
Ramírez, G.
8d31524f-613d-40a8-9386-fae3cc77747c
Recio, F.J.
c1569d6a-c8ca-4987-8313-01ef4c6cf776
Herrasti, P.
9ec58bb1-128c-4204-853f-804a91926275
Ponce De Leon Albarran, C.
508a312e-75ff-4bcb-9151-dacc424d755c
Sirés, I.
85e095d9-c3fa-48e2-aff3-65f0f4b2e4b4
Ramírez, G., Recio, F.J., Herrasti, P., Ponce De Leon Albarran, C. and Sirés, I.
(2016)
Effect of RVC porosity on the performance of PbO2 composite coatings with titanate nanotubes for the electrochemical oxidation of azo dyes.
Electrochimica Acta, 204, .
(doi:10.1016/j.electacta.2016.04.054).
Abstract
Reticulated vitreous carbon (RVC) of different porosities (20, 45, 60, 80, and 100 ppi—pores per inch) has been used as a large surface area substrate for preparing 3D-like PbO2 coatings (RVC/PbO2) as well as composite coatings with hydrothermally synthesized titanate nanotubes (RVC/PbO2/TiNT) by galvanostatic electrodeposition from baths containing lead(II) methanesulfonate and methanesulfonic acid. The effect of the RVC porosity on the coating thickness, the electrocatalytic behaviour and the ability to remove the colour and total organic carbon (TOC) from solutions containing the azo dye Methyl Orange has been systematically assessed. As shown from scanning electron micrographs, the greatest thickness (up to 120 ?m) was obtained using > 60 ppi, but the ?-PbO2 nanocrystallytes mainly grew on the external surface, leaving mostly uncoated inner RVC stripes and ending in planar-like PbO2-based electrodes. In contrast, thinner but perfectly adherent and homogeneous coating of the inner and outer surface was achieved with 20-60 ppi, showing electrodes with an optimal three-dimensionallity. This was especially confirmed by cyclic voltammograms for the composite coatings, as deduced from their highest electroactivity that can be related to enhanced adsorption onto the TiNT clusters and the larger ability to produce active PbO2(radical dotOHOH). The comparative electro-oxidation of 0.25 × 10?3 mol dm?3 Methyl Orange acidic solutions in 0.05 mol dm?3 Na2SO4 at 0.6 A demonstrated that RVC (45 ppi)/PbO2/TiNT was the optimum material. It allowed the quickest decolourisation, reaching 60% in 2.5 min and > 98% at 45 min, and > 55% TOC abatement at 240 min. The anode presented a perfect surface coverage, with no evidence of RVC degradation. The effect of dye concentration and supporting electrolyte nature was studied, revealing a very positive effect of NaCl.
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Accepted/In Press date: 11 April 2016
e-pub ahead of print date: 12 April 2016
Published date: 20 June 2016
Organisations:
Energy Technology Group
Identifiers
Local EPrints ID: 393176
URI: http://eprints.soton.ac.uk/id/eprint/393176
ISSN: 0013-4686
PURE UUID: 383da311-73b2-4792-9e58-a9b99f5f3866
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Date deposited: 22 Apr 2016 09:34
Last modified: 15 Mar 2024 05:31
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Author:
G. Ramírez
Author:
F.J. Recio
Author:
P. Herrasti
Author:
I. Sirés
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