Trifunctional Bimetallic Nitride Electrocatalyst

Das, Trishalina (2021) Trifunctional Bimetallic Nitride Electrocatalyst. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS Dissertation of Trishalina Das (16MS011)) 16MS011_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (3MB)

Abstract

Transition metal nitrides are a class of compounds known for their electronic conductivity and durability. We have used these nitride phases as electrocatalysts for OER, ORR and HER. The catalysts are prepared via nitridation of precursors using NH3 gas. The precursors for these catalysts are Prussian blue analogues (PBA) which are easily formed via the coprecipitation process. The time and temperature were varied to get different nitride phases from the same precursor. The resultant catalysts formed were characterized with the help of PXRD and CHN analysis. Further, morphological study and elemental mapping were performed by FESEM imaging and EDAX spectra. All the nitride catalysts were electrochemically characterized with the help of LSV, Tafel analysis, EIS and ECSA studies. We observed that the CoFe nitride sample heated at 380oC for 4 h has Pt-like HER activity and thus, this catalyst was further studied at changing pH to check for its pH universal applicability. The stability test was performed using chronopotentiometry for 74 h. It was observed that the nitride phase remains stable even after 74h. For OER and ORR decent activity was observed for the CoFe nitride sample heated at 380oC for 2 h. The outstanding HER performance is attributed to the presence of the zero-oxidation state of the metal which acts as an active site for HER due to the incorporation of nitrogen into the metal lattice.

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