Synthesizing and Characterizing Cobalt-Molebdynum Electrocatalysts Supported by Carbonaceous Nanomaterials

Abstract

This thesis explores the synthesis, characterization, and electrochemical behavior of nanocomposites composed of cobalt (Co) and molybdenum (Mo) deposited onto graphene oxide (GO), COOH-functionalized multi-walled carbon nanotubes (CNT-COOH), and blends of these two graphitic nanomaterials. The study aims to investigate the structural, morphological, and electrocatalytic properties of these nanocomposites synthesized via a hydrothermal method. Using a combination of analytical techniques including Raman Spectroscopy, Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray Photoelectron Spectroscopy (XPS), Cyclic Voltammetry (CV), Chronoamperometry, and UV-vis Spectroscopy, the nanocomposite structures were comprehensively characterized. SEM imaging demonstrated differential deposition of CoMo particles, demonstrating higher affinity and deposition on CNT-COOH compared to GO. EDX and XPS findings confirmed successful deposition of Co and Mo sulfides and oxides on both supports. According to XPS data, cobalt sulfides, molybdenum dioxide, and molybdenum disulfide were the dominant species synthesized in CoMo-CNT-COOH and CoMo-GO, whereas the prevalent species in CoMo-CNT-COOH-GO were cobalt and molybdenum sulfides. Electrochemical analyses, particularly CV tests, unveiled unique electro-oxidative activity of CoMo-CNT-COOH for Methyl Orange (MO) analyte at -0.4 V. CoMo-CNT-COOH exhibited approximately 68% optimum electrooxidation of MO after 5 hours for 100 mL solution initially made of 30 ppm MO and 0.5 molar sulfuric acid, indicating potential for environmental remediation applications.