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This work shows the potential application of carbon materials prepared by three different ionic liquid-based methods, using 1-butyl-3-methylimidazolium methanesulfonate [bmim][MeSO3], for electrochemical supercapacitors. The effects of [bmim][MeSO3] on morphology, texture and surface chemistry of prepared materials has been explored by SEM/TEM, N2/CO2 adsorption measurements and XPS. The results indicate the possibility of synthesis of carbon materials with tunable physicochemical properties using ionic liquid based methods. The charge storage behavior of all materials was studied in three different pH aqueous electrolytes. The pseudocapacitive and double layer contributions were estimated and discussed from the aspect of the textural changes and the changes of the chemical composition of surface functional groups containing heteroatoms. C[dbnd]O type functional groups, with the contribution of COOH groups, were found to be responsible for a different amount of charge, which could be stored in alkaline and acidic electrolytic solution. The material prepared by direct carbonization of [bmim][MeSO3], showed the best electrochemical performance in alkaline electrolyte with a capacitance of 187 F g−1 at 5 mV s−1 (or 148 F g−1 at 1 A g−1), due to the contribution of both electric-double layer capacitance and pseudocapacitance which arises from oxygen, nitrogen and sulfur functional groups.

Palladium ion-exchanged zeolite X (PdX) was prepared by zeolite impregnation with palladium acetylacetonate, followed by thermal degradation of the salt. PdX was characterised using SEM-EDS, ICP-OES and XRD. Analysis revealed presence of 7.78 wt.% of Pd in the form of PdO. Subsequently, PdX was tested for hydrogen evolution reaction (HER) in alkaline medium using linear scan voltammetry, chronoamperometry and electrochemical impedance spectroscopy measurements. The influence of addition of carbon black on the materials catalytic performance was also investigated. The HER kinetic parameters, including Tafel slope, exchange current density and activation energy, were determined. In order to provide atomic-level insights, experimental results were complemented by density functional theory calculations. It is suggested that favourable hydrogen adsorption energetics on PdO is responsible for efficient HER catalysis by this novel electrocatalyst. (c) 2017 Elsevier Ltd. All rights reserved.