Despite their high activity, noble-metal-based electrocatalysts are expensive, and this limits their employment in real applications. To date, both of these half-reactions have relied on noble-metal-based electrocatalysts to reach their best performance, namely Pt for HER, and IrO 2 and RuO 2 for OER. Notably, OER is more kinetically sluggish compared to HER, as it is a four-electron transfer reaction, while HER requires only two electrons. In a water electrolyzer, water electrolysis is separated into two half-reactions: hydrogen evolution reaction (HER) happens at the cathode, i.e., 2H + + 2e − → H 2 (under acidic conditions), while oxygen evolution reaction (OER) occurs at the anode, i.e., 2H 2O → O 2 + 4H + + 4e −. The outstanding electrocatalytic properties and high conductivity, along with the high S-doping level, render S-CNHs a promising bifunctional electrocatalyst for water splitting.Įlectrochemical water splitting is a cost-effective clean method for breaking down water to hydrogen (H 2) and oxygen (O 2) and is absolutely important in hydrogen economy. Additionally, S-CNHs showed significantly lower Tafel slope value and lower current resistance compared to oxidized and pristine CNHs for both electrocatalytic reactions. RHE for oxygen and hydrogen evolution reaction, respectively. Specifically, S-CNHs showed excellent activity and durability for both O 2 and H 2 evolution reactions, by showing low overpotential at 1.63 and −0.2 V vs. The S-CNHs were thoroughly characterized by spectroscopic, thermal and electron microscopy imaging means and then electrocatalytically screened.
Initially, oxidation of CNHs followed by thermal treatment with the Lawesson’s reagent resulted in the formation of S-CNHs with the sulfur content determined as high as 3%. Sulfur-doped carbon nanohorns (S-CNHs) were prepared by an easy one-pot solvothermal process and were employed as efficient electrocatalysts towards water splitting.
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