Silver deposition optimization process on ultrananocrystalline diamond applied to nitrate reduction

Author(s)

Oishi, Silvia Sizuka ^[1] ; Couto, Andrea Boldarini ^[1] ; Botelho, Edson Cocchieri ^[2] ; Ferreira, Neidenei Gomes ^[1]

Affiliation

^[1] INPE, Av Astronautas 1758, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[2] Univ Estadual Paulista, UNESP, Dept Mat & Tecnol, Guaratingueta - Brazil

• Document type: Journal article
• Source: ENVIRONMENTAL TECHNOLOGY; v. 42, n. 4, p. 640-647, FEB 10 2021.
• Web of Science Citations: 5

Abstract

Nitrate is a serious contaminant of ground and surface water, which cause high concern in the field of health and environmental protection. In this work, a ternary composite of silver/boron-doped ultrananocrystalline diamond/reticulated vitreous carbon (Ag/B-UNCD/RVC) was prepared and its electrocatalytic activity for nitrate reduction was examined. B-UNCD films were grown by hot filament chemical vapour deposition technique on RVC after a substrate seeding process improvement using 4 nm diamond powder. Compared to conventional 0.25 mu m diamond seeding, this new procedure allowed uniform RVC coverage avoiding its etching process during diamond growth, in addition to obtaining more reproductive electrodes. In order to improve the catalytic effect of B-UNCD/RVC electrodes for nitrate reduction, silver deposition was performed on B-UNCD surface after oxidation for 10, 20 and 30 min in 0.5 mol L-1 H2SO4 solution using a potential of 2 V vs. Ag/AgCl. The most oxidized diamond film (30 min of oxidation) presented the highest silver deposit and particle adhesion. Thus the electrochemical response to nitrate of B-UNCD/RVC oxidized for 30 min was compared to that of RVC and B-UNCD/RVC electrodes showing the important Ag influence in the catalytic process. {[}GRAPHICS] . (AU)

• FAPESP's process: 16/13393-9 - Semiconductor, polymeric, and carbonaceous composite electrodes ayming the synergy between water cleaning and energy storage processes
• Grantee: Neidenei Gomes Ferreira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/27164-6 - Production and characterization of reticulated vitreous carbon/nanodiamond/silver nanoparticles composites used for nitrate removal
• Grantee: Silvia Sizuka Oishi
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/10118-0 - Study and application of electrochemical technology for the analysis and degradation of endocrine interferents: materials, sensors, processes and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants