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The development of low-cost, high-activity oxygen evolution reaction (OER) catalysts is crucial for the scalable production of hydrogen through water electrolysis. Among all potential candidates, transition metal silicides have emerged as promising alternatives to noble metal-based catalysts due to their low electrical resistance, high chemical inertness, and excellent thermal stability. This thesis focuses on the polymer-derived ceramics (PDC) route to synthesize a series of transition metal silicide electrocatalysts, including monometallic Ni₂Si, bimetallic FeₓSiᵧ/Ni₂Si, and mid-entropy silicide. The PDC approach enables a unique strategy in which the microstructure can be designed at the molecular level. Following the polymer-to-ceramic transformation, this route enables to the formation of crystalline transition metal silicides homogeneously dispersed in the SiOC matrix. Additionally, the in-situ formed carbon and the development of a porous architecture contribute to the individual structural features. Furthermore, the phase evolution, crystallinity, elemental distribution, and the ordering of carbon are precisely tailored by adjusting the pyrolysis temperature, thereby enhancing the electrocatalytic performance of the resulting ceramics. Firstly, the porous SiOC-supported Ni₂Si catalyst was prepared using polystyrene (PS) as a pore former and pyrolyzed at 1400 ºC, achieving an overpotential of 336 mV vs. reversible hydrogen electrode (RHE) at 10 mA cm⁻² in 1 M KOH. In the second stage, the incorporation of Fe led to the formation of Ni₂Si/FeₓSiᵧ/SiOC composite. With the optimal composition containing 30 wt% Fe, the catalysts delivered an overpotential of 323 mV at 10 mA cm⁻² in 1 M KOH. In the final stage, mid-entropy silicide with a single-phase (FeCoNi)₂Si structure and uniformly distributed metal atoms was synthesized above 1000 ºC. The as-prepared ceramics exhibited an overpotential of 320 mV at 10 mA cm⁻² in 1 M KOH and retained 79% of the initial current density after 10 h. The obtained PDC ceramics exhibit high activity for OER, benefiting from the following factors: (1) catalytically active crystalline transition metal silicides, which provide abundant active sites; (2) in-situ formed carbon network derived from high-carbon-content polymeric poly(organo)siloxane SPR-684 precursor, which facilitates rapid charge transfer; and (3) a porous architecture, which enhances electrolyte penetration and active site accessibility. Overall, this thesis demonstrates that the PDC method is a versatile and practical route for synthesizing transition metal silicides in SiOC-based composite catalysts. This process enables the design of compositions and microstructures. Specifically, the process provides fundamental insights into the relationship between thermal treatment, phase evolution, and catalytic properties. Additionally, the synthesized transition metal (FeCoNi) silicides catalysts exhibit competitive OER activity. Therefore, this research not only expands the application of PDC catalysts in water splitting but also offers a pathway toward sustainable, non-noble metal-based energy conversion systems.