The catalytic reaction of ammonia synthesis is of paramount importance in the chemical industry, mainly for fertilizers production. , The reaction is equilibrium limited and is favored by low temperatures and high operating pressure. Since the pioneering work of Haber and Bosch the industrial ammonia synthesis is carried out over potassium-promoted Fe catalysts at pressures up to 300 bar. Here we show that the catalytic activity of state-of-the-art fully promoted industrial ammonia synthesis catalysts can be enhanced by up to 1300% by interfacing the catalyst with a proton conductor (CaIn0.1Zr0.9O3 - α) and electrochemically supplying protons to the catalyst surface. The rate increase is up to 6 times larger than the rate of proton supply to the catalyst. This is the first demonstration of the effect of electrochemical promotion, or non-Faradaic electrochemical modification of catalytic activity (NEMCA) − using a commercial catalyst and under high (50 bar) pressure. It is also the first demonstration of scale-up of an electrochemically promoted catalytic reactor as 24 electrically connected catalyst pellets were used. The results could in principle lead to a substantial decrease in the operating temperature and pressure of ammonia synthesis reactors.

No abstract

No abstract

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.

No abstract

No abstract

No abstract

This work reports for the first time the removal of 17α-ethynylestradiol (EE2), a synthetic estrogen hormone, from secondary treated effluents by electrochemical oxidation. Experiments were conducted in a single compartment reactor comprising a boron-doped diamond (BDD) anode and a zirconium cathode. EE2, in the range 100-800 µg L −1 , was spiked in the postchlorination effluent of a municipal treatment plant and oxidized at 0.9-2.6 mA cm −2 current density. Complete degradation of 100 µg L −1 EE2 was achieved in 7 min at 2.1 mA cm −2 and inherent conditions, while the addition of 0.1 mol L −1 NaCl achieved removal in just a few seconds. The process was then tested in the pre-chlorination effluent at 2.1 mA cm −2 and inherent conditions; complete E. coli killing and EE2 removal occurred in just 1.5 and 3.5 min, respectively, while overall estrogenicity (assessed by the YES assay) and residual organic matter (in terms of chemical oxygen demand (COD)) decreased by 50% and 85% after 30 min, respectively. These results clearly show the potential of BBD electrochemical oxidation to serve as an efficient tertiary wastewater treatment.