Fabrication of Bingöl pollen self-assembled monolayer films on copper as a novel cathode for electrochemical hydrogen production

Abstract

Preparation of a thin organic film on metallic electrodes can protect substrates against corrosion. These organic underlayers also help electrodeposition of metallic electrocatalysts as well as enhance the quality and performance of electrodes. In this study, a thin self-assembled monolayer film of Bingöl pollen (BP-SAM) was fabricated on a copper substrate (Cu/BP-SAM) in pure water as solvent. The film was prepared by exposing a Cu substrate to a 1000 ppm aqueous pollen solution for 24 h assembly time. Then, a small amount of Ni, known for its good catalytic properties for water splitting process, was electrodeposited over the previously assembled SAM film (Cu/BP-SAM/Ni) to enhance its catalytic effect for hydrogen evolution reaction. The modified surfaces were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), and contact angle (CA) studies. Water splitting activity of the Cu/BP-SAM and Cu/BP-SAM/Ni electrodes were investigated in 6 M KOH solution at 298 K. The data obtained indicated that the modification of Cu surface with BP-SAM and BP-SAM/Ni reduces polarization resistance (Rp) by 35.3% and 84.4%, respectively at −100 mV cathodic overpotential. The BP-SAM films were adherent to the Cu substracte and have a uniform structure. Ni particles were homogenously deposed over the SAM film and have high quality. The Cu/BP-SAM/Ni electrode has promising electrochemical time-stability during the electrolysis and losses only 6.5% of its activity during the long-time electrolysis.