Bimetallic Heterogeneous Catalysts for Water Electrolysis

Mura, Maglu (2025) Bimetallic Heterogeneous Catalysts for Water Electrolysis. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Maglu Mura (18RS069)) 18RS069.pdf - Submitted Version Restricted to Repository staff only Download (9MB)

Abstract

Noble metals such as platinum, iridium, and ruthenium, though highly efficient for water electrolysis, are limited by their scarcity, high cost, and instability under harsh operating conditions, making them unsuitable for large-scale or long-term applications. Their extraction is environmentally taxing and geographically constrained, while their catalytic bifunctionality is inadequate. Pt excels in HER but not OER, and RuO2/IrO2 shows the opposite trend. In contrast, earth-abundant bimetallic catalysts offer a more sustainable and cost-effective alternative, with tunable electronic structures, improved charge transfer, and enhanced catalytic properties due to synergistic effects. These systems avoid the limitations of metal-free catalysts with poor conductivity, and complex multi-metallic systems having high cost and difficult synthesis, providing a promising pathway toward efficient, stable, and bifunctional electrocatalysts for water splitting. This thesis moves beyond conventional investigations into the catalytic activities of various material classes such as immiscible alloys, interstitial bimetallic nitrides, and unconventional spinel oxides for water electrocatalysis. Instead, it optimizes the catalytic performance through detailed correlations between crystal structure, electronic properties, and morphology. Despite significant progress, several challenges persist with these electrocatalysts, including challenges in synthesising pure single crystallographic phases, low electronic conductivity, defect-rich grain boundaries causing poor conductivities, and surface degradation under extended oxidative potential. This work explores strategies to address these limitations and proposes potential solutions.

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