Research Projects

The future of the energy footprint will depend on the availability of renewable and sustainable energy resources. Production of hydrogen through water splitting using solar conversion is the ultimate renewable and sustainable energy source where electricity is produced with water as the sole product. Since hydrogen does not exist naturally on earth, it must be produced to be used. Hydrogen production through water splitting requires a hydrogen evolution reaction (HER) and suitable electrocatalyst. For HER, the benchmark electrocatalyst is platinum (Pt). Pt being expensive and scarce, a substitute for noble metal electrocatalyst must be found with earth abundant materials for low-cost and environmentally friendly production of hydrogen. Finding noble metal-free electrocatalysts has therefore been the focus of a scientific tour de force in recent years. Transition metal nitrides (TMNs), being formed with earth abundant elements (N₂ ~78%; TM~few %) are serious contenders, since (i) their electronic configuration is similar to a noble metal (ii) electrical conductivity is low and (iii) corrosion resistance is superior to Pt. In particular, some TMNs appearing late in a d-series like Fe2N, Co4N, Ni3N, Cu3N have exhibited a good HER activity but their thermal and chemical stability lacks. Since the formation enthalpies of such late TMNs is high, their synthesis and structural integrity has always remained a concern. The suggested remedies are: (i) altering the synthesis energetics by doping or alloying with other TMs, (ii) tuning of composition/N stoichiometry and (iii) a heterostructure approach. In the proposed research work, we aim to perform a systematic study on earth abundant late TMNs viz. Fe-N, Co-N, Ni-N and Cu-N family of compounds to establish a correlation between the electrochemical activity and (i) structure, (ii) composition, (iii) type and quantity of dopants and (iv) role of interfaces in heterostructures. It is proposed that by carefully utilizing laboratory and synchrotron-based techniques physical and electronic structure, atomic pair distances and interdiffusion will be measured and their correlation with the electrochemical activities will be established. The necessary methodology and expertise for synthesis of TMNs using reactive/co-sputtering, measurement of physical and electronic structure using x-ray diffraction and absorption; interdiffusion using x-ray/neutron reflectivity/secondary ion mass spectroscopy already exists with the PI. An electrochemical workstation is required to optimize the electrocatalytic performances of developed TMNs. A concurrent approach where the synthesis, structural optimization and electrochemical activity measurements will go hand-in-hand will enable the objectives of the proposal to be met. Thus, the realization of noble metal-free, thermally and chemically stable electrocatalysts leading to sustainable and environment friendly water splitting becomes feasible through this work.