Multi-metallic Nanostructures for Tailored Water Electrolysis

Parvin, Sahanaz (2022) Multi-metallic Nanostructures for Tailored Water Electrolysis. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Sahanaz Parvin (15RS053)) 15RS053.pdf - Submitted Version Restricted to Repository staff only Download (13MB)

Abstract

Earth-abundant catalysts based on single or multi-metals are the most promising substitutes for noble metal-based catalysts for electrocatalytic water splitting reactions. Attuning the structure-property relationship in the nanomaterials result in the efficient activity of the electrocatalysts. In introductory section, renewable energy conversion and storage systems along with different types of catalysts and their structure-property relationship are discussed. In materials and methods, the physical and electrochemical characterization methods are discussed. In chapter 3, a self-supported electrode is fabricated by electrodepositing NiCo-LDH on Cu wires which achieves a very high current density at low overpotentials, with pH-universal activity. In chapter 4, the same current collector with electrodeposition of Ni73Mo alloy which shows HER activity in both acidic and alkaline pH. A homologous OER catalyst is fabricated by electrodepositing NiMo-hydroxide on Ni foam, where both the catalysts show an unfavourable charge transfer from Mo to Ni accelerating the HER activity. In chapter 5, the in situ ion intercalation between the 1T-WS2 layers occur during formation of the two-dimensional 1T-WS₂-NiCo-LDH heterostructure facilitating the mass diffusion. The larger density of states near the Fermi level increases both HER and OER efficiency whereas the charge transfer from LDH to WS2 improves OER activity. In chapter 6, the introduction of oxygen defects in amorphous Co-Fe oxide, enables it to act as a bifunctional electrocatalyst. On integration with the perovskite solar cell, the electrolyser delivers a 9.3% solar-to-hydrogen efficiency. The designing of the nanostructure catalysts and manoeuvring their electronic and structural property can open up a new avenue for future applications of these catalysts. In chapter 7, summary and future prospects are discussed.

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