@InProceedings{OishiCoutBoteFerr:2017:EfSiPa,
author = "Oishi, Silvia Sizuka and Couto, Andrea Boldarini and Botelho,
Edson Cocchieri and Ferreiraa, Neiden{\^e}i Gomes",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {} and
{Universidade Estadual Paulista (UNESP)} and {Instituto Nacional
de Pesquisas Espaciais (INPE)}",
title = "Effect of silver particles electrodeposited on reticulated
vitreous carbon for nitrate reduction",
year = "2017",
organization = "ECS Meeting, 232.",
abstract = "Nitrate is a serious contaminant of ground and surface water,
which cause high concern in the field of health and environmental
protection. Many processes have been used for nitrate removal and
the electrochemical treatment is one of the most efficient due to
its advantages regarding low cost effectiveness and ability to
treat highly concentrated nitrate effluents. The cathode material
is an important variable for the nitrate electroreduction process
and the development of new electrodes to improve their catalytic
activity is a challenge. Modification of electrodes by
electrodeposition of metals has been frequently used for
electrocatalysis of various reactions in solution and carbon
materials are often used as supports for electrocatalysts. In this
work, the reticulated vitreous carbon (RVC) was used as support
for silver eletrodeposition and the effect of different parameters
(applied potential, AgNO3 concentration and deposition time) on
the morphology and electrocatalytic activity for nitrate reduction
was studied. RVC was processed using poly(furfuryl alcohol) (PFA)
resin synthesized according to the best condition established
previously. Polyurethane foams with 70 ppi (pores per inch) were
used as matrix for the PFA anchorage and after curing, they were
heat treated at 1000 °C. All electrochemical experiments were
performed in a conventional three electrode cell, using the RVC
with electrodeposited Ag as working electrode, a Pt screen and
Ag/AgCl as the counter and reference electrodes, respectively. The
deposition potentials were chosen through cyclic voltammetry at
0.1, -0.3 and -0.7 V vs Ag/AgCl that can be related to the
following regions, respectively: onset of Ag deposition, massive
deposition and diffusion controlled deposition. The AgNO3
concentrations solutions used were 5, 10 and 20 mmol L-1, and the
deposition times applied were 10, 60 and 180 s. The morphologies
obtained by field emission scanning electron microscopy (FESEM)
showed that Ag deposition is not uniform due to the RVC
three-dimensional structure. Ag dendrites were formed on the
highest RVC stems as shown in Figure 1. Ag aggregates of different
sizes and shapes dispersed on the entire electrode surface could
be observed depending on the experimental condition employed and
sample depth. Difference in electrocatalytic activity of the
Ag/RVC electrodes for nitrate reduction was confirmed by cyclic
voltammetry in 0.1 mol L-1 K2SO4 solution containing 0.01 mol L-1
KNO3 and varied with the Ag amount on electrode surface in
addition to its morphology.",
conference-location = "National Harbor, MD",
conference-year = "01-05 Oct.",
language = "en",
urlaccessdate = "28 abr. 2024"
}