Developing electrochemical methodologies towards addressing challenges in flow energy conversion technologies

Gaddam, Raghuram

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https://hdl.handle.net/2142/132752 Copy

Description

Title

Developing electrochemical methodologies towards addressing challenges in flow energy conversion technologies

Author(s)

Gaddam, Raghuram

Issue Date

2025-11-06

Director of Research (if dissertation) or Advisor (if thesis)

Rodríguez-López, Joaquín

Doctoral Committee Chair(s)

Shoemaker,, Daniel

Committee Member(s)

• Perry, Nicola H.
• Zhang, Yingjie

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Electrochemistry, Electrocatalysis, High-throughput screening, Energy storage, Redox-flow batteries, Scanning electrochemical microscopy, Electrodeposition, Flow-cell, Interfaces.

Abstract

Electrolyzer technologies for sustainable fuel production face critical catalyst optimization challenges, particularly in developing energy-efficient alternatives to the oxygen evolution reaction that dominates electrolyzer energy consumption. This dissertation presents electrochemical methodologies developed to systematically address catalyst discovery and optimization for glycerol electrooxidation as a promising anodic reaction that can significantly reduce electrolyzer energy requirements while producing valuable chemicals from biomass waste. Beginning with fundamental interfacial characterization, an SECM-based spot analysis methodology was established that quantifies heterogeneous electron transfer kinetics and identifies deviations from ideal electrochemical behavior at carbon electrode interfaces. Building on these diagnostic capabilities, a modified flooded microwell SECCM approach was developed that overcame meniscus instability issues in alkaline media to enable screening of bimetallic catalyst arrays, demonstrating superior performance of Au-Pd systems over other bimetallic combinations for glycerol electrooxidation. However, the inherent limitations of scanning probe techniques—particularly restricted scalability, limited automation potential, and low experimental throughput—necessitated the development of more versatile screening architectures. To address these fundamental bottlenecks, an individually addressable electrode array methodology was implemented, which integrated with semi–automated synthesis and characterization protocols, enabled the successful screening of unique Au electrodeposition conditions and the identification of optimal parameters that correlate specific surface facets with electrocatalytic performance. This automated platform was extended to systematically evaluate 77 Au-Pd bimetallic compositions, revealing that ~45% Pd loading represents the optimal catalyst formulation that combines high activity, favorable kinetics, and great stability across multiple performance metrics. Validation through scaled-up flow electrolyzer experiments confirmed enhanced C-C bond cleavage activity and stable long-term operation, demonstrating successful translation from microscale screening to practical electrochemical systems. By systematically addressing the methodological bottlenecks that have constrained electrocatalyst discovery, this work provides scalable approaches for rational catalyst design that enable efficient biomass valorization in electrolyzer systems, contributing essential capabilities for sustainable chemical production and industrial decarbonization.

Graduation Semester

2025-12

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/132752

Copyright and License Information

Contents of this thesis are pending publication.

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