This review presents studies and investigations of the use of gold catalysts in environmental applications, from the oxidation of CO and volatile organic compounds (VOCs) in environmental technologies to the production of hydrogen, a non-polluting energy source, in the water-gas shift (WGS) reaction. It summarizes a variety of results, from the discovery made by Haruta et al. about the catalytic behaviour of gold in CO oxidation, to the use of gold-based catalysts in environmental remediation, by the catalytic removal of different types of VOC using a wide variety of oxide supports and finally to the use of this highly active noble metal in WGS applications. It also discusses gold loading methods, comparing them in terms of simplicity, efficiency and the resultant particle size and dispersion of Au over various supports. The application of different types of supporting materials is also presented, with a critical discussion of the parameters affecting the choice and use of such materials, i.e. how the support interacts with gold particles and with pollutant molecules along with the advantages a support offers to VOC oxidation and WGS reactions. It ends by highlighting the potential of gold catalyts in the future.

Catalytic total oxidation is an efficient technique for treating VOCs, which are mainly emitted by solvent-based industrial processes. However, studies of the catalytic oxidation of VOCs in combination with other pollutants are very limited, despite the fact that this is a key step of knowledge before industrial application. During the oxidation reaction, the behavior of a molecule may change depending on the reaction mixture. For the treatment of an effluent loaded with VOCs, it is necessary to carefully select not only the catalytic material to be used but also the reaction conditions. Indeed, the catalytic oxidation of a component in a VOCs mixture is not predicted solely from the behavior of individual component. Thus, the objective of this small review is to carry out a study on the effect observed in the case of the oxidation of a VOCs mixture or in the presence of water, NO_X or sulfur compounds.

Catalytic total oxidation is an effective technique for the treatment of industrial VOCs principally resulting from industrial processes using solvents, and usually containing mono-aromatics (BTEX) and oxygenated compounds (acetone, ethanol, butanone). The catalytic total oxidation of VOCs on noble metal materials is effective. However, the cost of catalysts is a main obstacle for the industrial application of these VOC removal processes. Therefore, the aim of this work is to propose an alternative material to palladium-based catalysts (which are suitable for VOCs’ total oxidation): a mixed oxide synthesized in the hydrotalcite way, namely CoAlCeO. This material was compared to four catalytic materials containing palladium, selected according to the literature: Pd/α-Al₂O₃, Pd/HY, Pd/CeO₂ and Pd/γ­Al₂O₃. These materials have been studied for the total oxidation of toluene, butanone, and VOCs mixtures. Catalysts’ performances were compared, taking into account the oxidation byproducts emitted from the process. This work highlight that the CoAlCeO catalyst presents better efficiency than Pd-based materials for the total oxidation of a VOCs mixture.