Redefining the landscape of ammonia electrooxidation, utilising molecular electrocatalysts

ongoing

Fuel cells represent highly efficient and non-polluting power devices that convert the chemical energy of a fuel into electrical power. Ammonia, as a fuel, is considered a potent alternative to the commonly used hydrogen because it has a lower cost per unit of stored energy and benefits from a well-established production and distribution infrastructure. The electrochemical NH3 oxidation reaction (eAOR) typically relies on Pt-based electrocatalysts due to their low overpotential and remarkable selectivity for N2. However, their susceptibility to durability problems exacerbates their already high cost and limited availability. A few recent studies have reported molecular eAOR catalysts, but evaluate them under homogeneous conditions, which are rarely relevant to energy-related applications. To make feasible catalytic systems out of molecular catalysts, their heterogenisation on electrode surfaces is necessary. Within the MSCA postdoctoral fellowship 'Elmar', I aim to construct catalytic films for eAOR, by encapsulating non-noble metal molecular complexes in carbon-based supporting materials. Those hybrid electrocatalysts will undergo electrochemical assessment to determine their efficiency and durability, and will be compared to a reference Pt/C catalyst. The performance of each electrocatalyst will be optimized by tuning the micro-environment of the molecular complex inside the film, and rationalized based on spectroscopic and spectroelectrochemical investigations. Overall, I aspire to establish an exemplary methodology for constructing, optimizing, and rationalizing electrocatalysts based on simple non-noble metal complexes. My ultimate goal is to create robust eAOR catalysts capable of competing with Pt-based ones. This endeavour can significantly contribute to the development of fuel cell technologies, that are expected to play an important role in the decarbonization of the EU’s energy system.