Hydrogenation of CO₂ over Ru/YSZ Electropromoted Catalysts

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.

A novel W-doped Ni-Mg mixed oxide catalyst for CO2 methanation

“…Ni 0.5 MgO x exhibited a relatively poor activity at temperature lower than 300 • C. Both Ni 0.8 MgO x and Ni 1.0 MgO x with higher Ni loadings showed enhanced activities towards CO 2 methanation, especially at low temperature. At 300 • C, the CO 2 conversion reached 70% over Ni 1.0 MgO x with 99% selectivity to CH 4 . As a reference, Ni/MgO(imp) showed a poor CO 2 conversion less than 20% at the same temperature, implying that the homogeneous precipitation preparation method improved the dispersion of active Ni species on Ni-Mg mixed oxide catalysts for CO 2 methanation.…”

“…Several efforts have been devoted to the development of effective and stable catalysts for this particular reaction since early 20th century [1,2]. Supported noble metal catalysts, such as Ru [3][4][5], Rh [6][7][8][9] and Pd [10][11][12] are well known for their excellent activity and stability in CO 2 methanation under relatively mild reaction conditions. Nevertheless, the large-scale application of these catalysts has been limited by their high cost.…”

“…The deactivation of catalysts by coke formation and sintering of metal particles is accelerated when a large amount of heat is released as the exothermal reaction further proceeds [16,24,25]. Besides, the poison effect of CO via the formation and the migration of mobile Ni(CO) 4 species on catalyst surface during the methanation reaction cannot be ruled out [15,26]. Nevertheless, several researchers substantiated that the formation of Ni-Mg solid solution was beneficial for the resistance against deactivation over MgO supported Ni catalysts [20].…”

Electrochemical promotion of CO 2 hydrogenation on Ru catalyst–electrodes supported on a K–β″–Al 2 O 3 solid electrolyte

“…The electrochemical promotion of CO 2 hydrogenation has been studied in the past over Cu [50,51], Rh [50], Pt [42,43,50,52], Pd [44], Ru [53,54] catalyst film electrodes deposited on YSZ [44,50,52,53,55], SrZr 0.90 Y 0.10 O 3Àa (H + conductor) [51] and b 00 -Al 2 O 3 (K + or Na + conductor) [42,43,44,54] ceramic supports.…”

One-Pot Synthesis of N,N′-dialkylureas via Carbonylation of Amines with CO2 Applying Y0.08Zr0.92O1.96 Mixed Oxide (YSZ-8) as a Heterogeneous Catalyst

“…It was reported to catalyze reactions such as oxidation of hydrocarbons [26], hydrogenation of CO and CO2 [27,28], electrochemically assisted NOX storage-reduction [29], and so on. In this study, yttria-stabilized ZrO2 (8 mol % Y, YSZ-8) was employed as a heterogeneous catalyst for the production of N,N′-dialkylureas via carbonylation of amines directly with CO2.…”