The combustion of light hydrocarbons finds an important application in volatile organic compounds (VOCs) abatement. Catalytic combustion is interesting in this domain, because it may be carried out at relatively low temperatures and under large air excess. For this purpose, precious metal-based catalysts are very performing, but the quest for a lower-cost alternative solution is necessary. In this field, conducting mixed oxides such as perovskites are good candidates, especially when they are electrochemically promoted. The present work shows that electrochemical promotion of catalytic activity (NEMCA effect) in propene total combustion can be carried out with La0.8Sr0.2Co0.8Fe0.2O3, an electron-conducting perovskite-type oxide, deposited on YSZ.

Electrochemical catalysts were used for environmental applications, such as the clean production of energy from propane and propene combustion, the elimination of VOC’s like propene and the NOx abatement All the selected electrochemical catalysts were composed of a Pt film deposited on YSZ, NASICON or CGO. It was found that all these chemical reactions can be electropromoted. Moreover, the reaction rates can be in-situ tuned by applying a polarisation. Furthermore, the selectivity of Pt-based electrochemical catalysts can be modified in order to avoid the formation of pollutant. Finally, EPOC can improve the lifetime of a catalyst by inhibiting its poisoning by carbonaceous species.

采用共沉淀-浸渍法制备了Pt/Co-Ba-Al-O催化剂，用X射线衍射、X射线吸收近边结构和扩展X射线吸收精细结构等手段表征了催化剂的微观结构，并在连续流动微型反应器上测定了催化剂对NOx的储存性能。载体经过800℃焙烧后，Co物种主要以四面体配位的铝酸钴相存在。在富氧条件下，高分散的小颗粒铝酸钴相促进了NO向NO2的转化，大大改善了催化剂对NOx的储存性能。铂物种则以小的金属原子簇形式存在，分散度很高。钴助剂的添加改善了氧化铝相的分散度，抑制了金属铂原子簇与载体的相互作用，使铂在催化剂表面分散得更均匀，从而有利于NOx的储存

A new NOx storage-reduction electrochemical catalyst has been prepared from a polycrystalline Pt film deposited on 8 mol% Y2O3- stabilized ZrO2 (YSZ) solid electrolyte. BaO has been added onto the Pt film by impregnation method. The NOx storage capacity of Pt-BaO/ YSZ system was investigated at 350℃ and 400℃ under lean conditions. Results have shown that the electrochemical catalyst was effective for NOx storage. When nitric oxides are fully stored, the catalyst potential is high and reaches its maximum. On the other hand, when a part of NO and also NO2 desorb to the gas phase, the catalyst potential remarkably drops and finally stabilizes when no more NOx storage occurs but only the reaction of NO oxidation into NO2. Furthermore, the investigation has clearly demonstrated that the catalyst potential variation versus temperature or chemical composition is an effective indicator for in situ following the NOx storage-reduction process, i.e. the storage as well as the regeneration phase. The catalyst potential variations during NOx storage process was explained in terms of oxygen coverage modifications on the Pt.

The origin of the electrochemical promotion of catalysis (EPOC) was investigated via oxygen temperature-programmed desorption (O2-TPD) from a polycrystalline Pt film interfaced with YSZ. TPD experiments were carried out under operating conditions similar to those used for catalytic activity measurements. This study has clearly shown that an anodic current generates the migration of ‘‘backspillover’’ ionic oxygen species from YSZ toward the Pt surface. These ionic species act as promoters and enable the formation of weakly adsorbed oxygen species coming from the gas phase which are more reactive and thus responsible for the activity enhancement. The effect of polarization is to carry or to remove the promoting ionic species on the Pt surface. Therefore, electrochemical promotion of catalysis can be considered as an electrically controlled metal support interaction, where the support is an O2- conducting solid electrolyte.