Surface engineered low-cost paper electrodes for enhanced electrocatalytic activity

Abstract

Hydrogen evolution reaction (HER) is considered the most promising way to produce clean and sustainable hydrogen energy. Carbon-based materials have been discovered to be efficient for catalyzing HER reactions in addition to conventional noble metal-based electrodes. Surface engineering of electrodes through simple methods are important to enhance the electrochemical properties and to keep the cost economical. Herein, we tried to understand the influence of simple electrochemical pre-treatment methods on Paper electrode (PPE) surface towards electrocatalytical activity. The pretreatment methods involving simple voltametric scanning and pre-anodization has been carried out under various electrolytic conditions and investigated for their role on electrochemical activities. The pretreated electrodes were thoroughly characterized with surface morphological and electrochemical techniques. The pre-anodized disposable paper electrode (PA-PPE- H2SO4) modified with pyrene butyric acid (PA-PPE- H2SO4-PBA) was found to show excellent electrochemical properties and exhibited a low-potential HER (Onset potential, Eonset = -0.1 V Vs. RHE) in 0.5 M H2SO4 with a Tafel slopes, 34.2 and 49.88 mV/ dec−1. The obtained results are substantially better than that of reported carbon-based electrodes, where the benefit of Platinum leaching out from the counter electrodes are speculated. The formation of edge-plane sites/defects, and functional groups on electrode surfaces and modification effect by PBA are the reason behind the increased the electrochemical response. Since paper has been used as a substrate for fabrication of the electrodes, possibility to use the same in future as a flexible current collector for self-powering wearable devices/sensors are anticipated.