Boron Doped Nanocrystalline Diamond/Reticulated Vitreous Carbon Composites Decorated with Silver Nanoparticles
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Boron Doped Nanocrystalline Diamond/Reticulated Vitreous Carbon Composites Decorated with Silver Nanoparticles Silvia S. Oishi1, Andrea B. Couto1, Edson C. Botelho2, and Neidenêi G. Ferreira1 1
Instituto Nacional de Pesquisas Espaciais (INPE), São José dos Campos, 12227-010, Brazil. Department of Materials and Technology, UNESP-Univ. Estadual Paulista, Guaratinguetá -SP, 12516-410, Brazil. 2
ABSTRACT Boron doped nanocrystalline diamond films (BDND) were grown on reticulated vitreous carbon (RVC) heat treated at 1000 and 1700 °C. Silver (Ag) nanoparticles were electrodeposited on RVC and RVC/BDND composites by potentiostatic reduction of AgNO3 solution. The samples were characterized by scanning electron microscopy, Raman spectroscopy, X-ray diffraction, and cyclic voltammetry. The samples conductivities influenced the Ag deposition amount as well as the Ag particle sizes where the smaller Ag particles were observed for RVC/BDND composites. The stability of Ag nanoparticles was also confirmed by cyclic voltammetry. INTRODUCTION Reticulated vitreous carbon (RVC) is a multifunctional material with a wide range of applications due to its high surface area, rigid structure, low resistance to fluid flow, and high thermal and electrical conductivities [1-3]. RVC can be used as matrix for boron doped nanodiamond (BDND) growing by combining these material properties such as the RVC large surface area and the diamond singular properties resulting in a novel composite material for electrochemical applications. Specifically, BDND films have been explored due to its high surface/volume ratio and its high electrical conductivity [4]. In addition, to enhance the BDND electrocatalytic activity for certain species, the deposition of metallic nanoparticles should be considered. In this context, silver (Ag) nanoparticles have had important applications since they have useful properties such as electrical conductivity, chemical resistance, bactericidal, and catalytic activity [5]. Therefore, in this work Ag nanoparticles were electrodeposited on RVC and RVC/ BDND composites. The BDND films as well as Ag nanoparticles depositions were conducted on RVC substrates heat treated at 1000 °C (RVC1000) and 1700 °C (RVC1700) to create a new composite material to be used as electrode in nitrate reduction. EXPERIMENTAL RVC was processed using poly(furfuryl alcohol) (PFA) resin synthesized according to the best condition previously established [6]. Polyurethane foams with 70 ppi (pores per inch) were used as matrix. Polyurethane foams were impregnated with PFA catalyzed with 3% w/w% of p-toluenosulfonic acid solution (60 w/v%) and cured in an oven for 1h in the following heating steps: 50, 70, 90, 110, and 130 °C. The cured material was heat treated in a tube oven up to 1000 °C, remaining for 1h at the final temperature, with a heating rate of 1 °C/min and nitrogen atmosphere. For the samples treated at 1700 °C, it was used a heating rate of 5 °C/min
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