Journal Article

Hydrogen Gas Generation Using Self-Assembled Monolayers Porphyrin on a Gold Electrode

Elghamry, Ibrahim, Alablan, Abdulrahman S, Abdelsalam, Mamdouh E

2023

Overview

A novel approach was used to synthesize the 5,10,15,20-tetrakis (p-thiophenol) porphyrin (TPTH-P) (2), which involved the demethylation of tetra (p-anisole) porphyrin (1) in the presence of ZnCl[sub.2] as a catalyst and DMF as a solvent at 100 °C. The demethylation step was followed by an acidification step with concentrated H[sub.2]SO[sub.4] to yield the desired TPTH-P (2) in an almost quantitative yield (95%). The chemical structure of the synthesized porphyrin thiol (TPTH-P) (2) was verified through spectroscopic techniques (NMR, IR, UV-Vis). The catalytic activity of TPTH-P in the hydrogen evolution reaction (HER) was investigated in 0.1 M of H[sub.2]SO[sub.4] and 1 M of KNO[sub.3]. A self-assembled monolayer (SAM) of TPTH-P was formed on a gold electrode. The immersion time during SAM formation and the electrochemical activation cycles in H[sub.2]SO[sub.4] were found to be important to enhancing the activity of the Au-TPTH-P electrode in the HER. Contact angle measurements and electrochemical techniques, including cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and chronoamperometry, were used to characterize and evaluate the electrochemical activities of the SAM.

• Publisher: MDPI AG
• Subject: Porphyrins / Thiols