The effect of electrochemical promotion of catalysis (EPOC or NEMCA effect) was investigated for the hydrogenation of CO2 using Ru catalyst electrodes supported on YSZ solid electrolyte pellets at temperatures 200–300 °C and ambient pressure. Methane was found to be the main reaction product at temperatures up to 240 °C, whereas CO dominated at higher temperatures. It was found that the O2– supply to the Ru surface causes a significant increase in the CH4 formation rate and selectivity, accompanied by a significant decrease in the rate of CO formation. This is a very rare case in which electrochemical promotion is found to promote a catalytic reaction and at the same time to poison a reaction proceeding in parallel with the promoted one. The faradic efficiency values were found to be on the order of 10–103, which are among the highest reported in the EPOC hydrogenation literature. The kinetic and electropromotion results can be interpreted, using the rules of electrochemical promotion, in terms of the changes in the surface RuO x /Ru ratio induced via potential application, as observed via ex situ XPS.

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The kinetics and the electrochemical promotion of the hydrogenation of CO2 over Ru‐catalyst electrodes deposited on yttria‐stabilized zirconia (YSZ) and (Na+)‐β“‐Al2O3 solid electrolytes are investigated at temperatures between 200 and 340 °C and pressures up to 5 bar. In the case of both the O2− conductor (YSZ) and the Na+ conductor (β”‐Al2O3), the selectivity for CH4 production is enhanced significantly when using a positive potential by supplying of O2− to, or removal of Na+ from, the catalyst surface. The opposite effect is observed when using a negative applied potential, which suppresses CH4 formation and enhances the production of CO through the reverse water–gas shift reaction. However, at low Na coverage, and under reducing conditions, both methanation and H2 production are promoted by the application of a negative potential. The observed electrochemical promotion behavior in conjunction with the reaction kinetics is consistent with the rules of electrochemical and chemical promotion.

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Preparation of carbon nanomaterials from agro-waste is a promising research area due to the low cost and high availability of agro-waste and the unique physical, chemical and electrochemical properties of agro-waste-derived carbon. Such prepared nanomaterials have been used as electrode materials after immobilizing them on other solid substrates such as glassy carbon, Au, and Pt electrodes. However, this immobilizing step is tedious and the substrate electrodes are expensive. Here we present a simple pyrolytic preparation of a substrate-free electrode consisting of interconnected nanostructured carbon from date palm leaflets for direct use as an inexpensive electrode material. The prepared nanostructure was characterized using field emission scanning electron micro-scopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and cyclic voltammetry. The cyclic voltammetry studies revealed the electrocatalytic properties of the prepared nanostructured electrode toward K 4 [Fe 4 (CN) 6 ] and hydroquinone (HQ) to be superior to those of the commonly employed glassy carbon electrode. The prepared nanostructured carbon electrode was deployed using amperometry to sensitively detect HQ, and showed a detection limit for HQ of 6.1 mM. This electrode was highly stable and selective for HQ in the presence of several test interferents. The developed electrode may thus be considered as a promising tool for sensing HQ.[a] Dr.