Air-Stable Nickel Phosphide Catalysts for Reductive Transformations

• Applicant: Dr. Constanze Neumann
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation ; Solid State and Surface Chemistry, Material Synthesis
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 566186537

Efficient catalysts are crucial for the sustainable production of chemicals. By lowering reaction barriers and maximizing the selectivity for the desired reaction product, a good catalyst lowers the heat input that is required, and minimizes the need for energy-intensive purification steps. The most efficient catalysts for many transformations, especially reduction reactions, are based on noble metals such as platinum and palladium. Not only are noble metals scarce and expensive, but their extraction is coupled to a large release of CO2. Transition metal phosphides have shown promise as noble-metal free alternatives, but low dispersion and facile oxidative damage of the catalyst surface limit their catalytic performance. The proposed project aims to ensure that an excellent dispersion of small (< 4 nm) nanoparticles can be accessed for a variety of transition metal phosphides and a wide range of supports. We will investigate an approach in which both the metal phosphide and a protective surface ligand can be accessed in one synthetic step. Preliminary results have shown that phenyl phosphate surface ligands can shield the surface of Ni2P from oxidative degradation without preventing efficient substrate access in catalytic transformations. By optimizing the structure of surface ligands, we aim to maximize the oxidative stability of metal phosphides as well as their performance in alkyne semi-hydrogenation and the reductive conversion of nitroarenes. Preliminary results show that through synthetic optimization, supported transition-metal phosphide catalysts can be accessed that rival the activity of palladium-containing benchmark catalysts. In the proposed work, we aim to demonstrate that transition-metal phosphide catalysis is likewise applicable to complex substrates and the catalysts can show comparable recyclability and operational convenience to currently employed noble-metal containing catalysts. The collected insights and optimized materials will be applied to the development of reductive coupling reactions of nitroarenes to furnish valuable substituted arylamines.

• DFG Programme: Research Grants