Enhanced activity of catalysts on substrates with surface protonic current in an electrical field - a review.

It has over the last few years been reported that the application of a DC electric field and resulting current over a bed of certain catalyst-support systems enhances catalytic activity for several reactions involving hydrogen-containing reactants, and the effect has been attributed to surface protonic conductivity on the porous ceramic support (typically ZrO2, CeO2, SrZrO3). Models for the nature of the interaction between the protonic current, the catalyst particle (typically Ru, Ni, Co, Fe), and adsorbed reactants such as NH3 and CH4 have developed as experimental evidence has emerged. Here, we summarize the electrical enhancement and how it enhances yield and lowers reaction temperatures of industrially important chemical processes.

Support effects on catalysis of low temperature methane steam reforming.

Low temperature (<500 K) methane steam reforming in an electric field was investigated over various catalysts. To elucidate the factors governing catalytic activity, activity tests and various characterization methods were conducted over various oxides including CeO, NbO, and TaO as supports. Activities of Pd catalysts loaded on these oxides showed the order of CeO > NbO > TaO Surface proton conductivity has a key role for the activation of methane in an electric field.

Effects of metal cation doping in CeO support on catalytic methane steam reforming at low temperature in an electric field.

Catalytic methane steam reforming was conducted at low temperature using a Pd catalyst supported on Ce M O ( = 0 or 0.1, M = Ca, Ba, La, Y or Al) oxides with or without an electric field (EF). The effects of the catalyst support on catalytic activity and surface proton hopping were investigated.

Key factor for the anti-Arrhenius low-temperature heterogeneous catalysis induced by H migration: H coverage over support.

Low-temperature heterogeneous catalytic reaction in an electric field is anticipated as a novel approach for on-demand and small-scale catalytic processes. This report quantitatively reveals the important role of proton coverage on the catalyst support for catalytic ammonia synthesis in an electric field, which shows an anti-Arrhenius behaviour.

First observation of surface protonics on SrZrO perovskite under a H atmosphere.

This is the first direct observation that surface proton hopping occurs on SrZrO perovskite even under a H (i.e. dry) atmosphere.