Novel catalysts for carbon dioxide reduction
In its Fourth Assessment Report, the Intergovernmental Panel on Climate Change (IPCC) states that the observed increase in anthropogenic greenhouse gas concentrations most probably accounts for global warming. In particular, fossil fuel burning seems to be one of the main culprits for the change in global average temperature. Of the potential renewable energy sources, solar energy is the most abundant. Photo- or electrocatalysis of CO2 provides new avenues for producing chemical fuels, thus providing an alternative to fossil fuels. The EU-funded project 'A new approach to electrocatalytic CO2 reduction based on supramolecular, dinucleating catalysts' (CO2REDUCTDINUCLEAT) synthesised novel ligands – molecules that bind to a central metal atom – and transition metals for coordination centres and tested their reactivity with CO2. Initially, scientists prepared a new family of ligands, some of them having the ability to generate bimetallic or multi-metallic complexes. Then, work was geared into studying the reactivity of the coordination complexes with certain chemical compounds. This enabled scientists to obtain an inorganic compound – copper hydride – that reacts with CO2, allowing them to derive formate derivates. The introduction of another chemical compound, silane, helped making this process catalytic. The team evaluated a variety of reaction conditions such as solvent, temperature and catalyst load of three different silane derivatives, obtaining remarkable product yields of nearly 95 %. CO2REDUCTDINUCLEAT generated different complexes based on naphthyridine skeleton, with some of them demonstrating an extraordinary ability to activate CO2. Conversion of CO2 to reduced chemical species using electrical energy – electrochemical reduction – represents a possible route for producing fuels, with CO2 as a feedstock. The newly synthesised complexes realised through the project's work should help in catalysing this process and at the same time provide carbon-neutral energy sources.
Keywords
Catalysts, carbon dioxide reduction, coordination complexes, solar fuels
