Síntese e caracterização de grafeno produzido a partir da serragem de madeira

Abstract

Graphene has received special attention in the research of several areas of knowledge, since its discovery in 2004, because of its peculiar properties not presented in other materials. In particular, its exceptional electronic properties, such as high mobility of carriers (electrons or holes), semi integer quantum Hall effect at room temperature, among others. Until now, the most used methods for graphene production have been chemical vapor deposition (CVD), heat treatment of silicon carbide (SiC) and reduction of graphene oxide. However, there is still room for simpler, economical and large-scale methods, such as, graphene produced from alternative materials, such as rice husk ash (RHA), sugar cane, among others. In this sense, the main objective of this work is to synthesize, characterize and produce graphene from wood sawdust (WS). For this purpose, WS was first burned at different temperatures (300, 400 and 500ºC) in a controlled time (40, 60, 120 minutes) for each temperature, obtaining wood sawdust ash (WSA). Next, the WSA samples were properly characterized using the following characterization techniques: X-Ray Fluorescence (FRX), Elemental CHN Analysis and Confocal Raman spectroscopy, in order to obtain information of the quantity and quality of carbon in the different analyzed samples. From the obtained results, it was verified that the best samples that had high carbon content were burned at the temperatures of 300 and 400ºC by a 60-minute oven stay. Raman spectroscopy showed the presence of D (~ 1350 cm-1) and G (~ 1580 cm-1) bands, which are the characteristic bands of carbonaceous materials. Subsequently, the chosen WSA was chemically activated with KOH in the proportion of 1 (WSA) to 4 (KOH) (1: 4). Through Raman spectroscopy it was verified that the chemically activated samples showed a band in the region of ~ 2690 cm-1, which is the characteristic band of the presence of graphene. Therefore, results of this work show the possibility of obtaining graphene from sawdust in a cheap and sustainable way, when compared to commercial graphene.