Tunable Plasmons in Photoelectrochemical Water Splitting: An Overview

ABSTRACT Surface plasmon resonance in metal nanostructures is a promising method for enhancing solar water splitting and hydrogen production. Tunable plasmons offer a transformative approach for designing plasmonic semiconductor photoelectrodes with improved solar‐to‐chemical energy conversion efficiency. Materials such as metal oxides, chalcogenides, and non‐noble metals are particularly well‐suited for achieving tunable plasmonic properties. These materials are abundant, cost‐effective, and have a broad plasmonic response, making them ideal for large‐scale renewable energy applications. Localized surface plasmon resonance in these materials is often induced by doping, which increases free‐carrier concentrations and enhances their interaction with solar radiation. The electronic band structures and optical properties of these materials can be finely tuned through advanced synthetic methods and nanoscale structural engineering. Such modifications improve light absorption, charge carrier dynamics, and interfacial catalysis, collectively boosting solar energy capture and conversion into chemical energy. This review explores the fundamental mechanisms of hot‐carrier generation and evaluates the potential of tunable plasmon‐based photoelectrodes in solar water splitting. It provides a scientific foundation for the rational design of next‐generation plasmonic systems for efficient energy conversion. This interdisciplinary field combines insights from plasmonics, surface chemistry, and nanomaterials science, highlighting its importance in developing sustainable energy solutions.