The chemical industry has changed the world and the living standards of many, particularly through contributions in the fields of petrochemicals, pharmaceuticals and nutritional supplements. Increasing concern for health and the environment has now placed meeting these goals within the context of sustainability and low environmental impact. Green catalysis is a main target. Catalysts make reactions happen easier and faster, but are not themselves consumed by the reactions so they can be used again and again. The EU-funded project NOMGCNP (Mesoporous graphitic carbon nitrides supported noble metal nanoparticles for green catalysis under visible light) was launched to synthesise highly efficient heterogeneous catalysts for organic reactions. Heterogeneous catalysts are in different phases than the reactants, typically solid catalyst systems used for reactions in a liquid solvent. Ease of separation of the catalyst from the product stream has facilitated development of continuous chemical processes (as opposed to batch processes). NOMGCNP scientists investigated several different heterogeneous catalytic systems. Mesoporous carbon nitride was used to support noble metal nanoparticles of gold (Au), palladium (Pd) or alloys (Au-Pd). The systems were moderately active in catalysing benzyl alcohol oxidation, but it was difficult to separate the catalyst from the reaction mixture afterwards. Au-Pd alloys supported on meso- and microporous carbide-derived carbons with very-high-surface areas demonstrated excellent activity for benzyl alcohol oxidation – more than 100 % higher than the commercially available active carbon-immobilised Au-Pd nanoparticles. Graphene oxide sheets were excellent inorganic stabilisers for immobilising Au-Pd nanoparticles. Researchers demonstrated the successful formation of highly accessible and well-dispersed Au-Pd nanoparticles immobilised with inorganic composites of graphene oxide sheets and intercalated titania to form ternary hybrid catalysts. They catalysed the oxidation of a range of alcohols with comparable activity and enhanced stability relative to similar catalyst systems stabilised on organic molecules such as polyvinyl alcohol or polyvinylpyrrolidone. Further, the ternary hybrid catalysts were ideally suited to direct synthesis of hydrogen peroxide from hydrogen gas and oxygen. Green catalysis is a major R&D focus. Progress will make a significant impact on the sustainability and eco-friendliness of a huge socioeconomically important market. NOMGCNP delivered novel catalysts to support the effort and the EU's position in the global market.
Chemical production, green catalysis, heterogeneous catalysts, carbon nitride, metal nanoparticles