Photocatalysis beyond band gaps and hot carriers: toward a unified view of semiconductor and plasmonic systems

Abstract

Photocatalysis stands at the forefront of efforts to address global challenges in sustainable energy and environmental remediation. In this review, we critically examine the two major classes of heterogeneous photocatalysts-plasmonic materials and semiconductors-highlighting their fundamental distinctions, catalytic mechanisms, and potential for driving light-induced chemical transformations. We first explore the fundamentals of plasmonic materials and semiconductors, highlighting key distinctions and overlaps in their photophysical properties, elucidating how these differences govern their photocatalytic performance and reaction pathways. This review further explores practical examples of photocatalytic reactions, including CO₂ reduction, N₂ reduction, and dry reforming of methane (DRM), illustrating the versatility, catalytic efficiency, and inherent limitations of each class of materials. Additionally, we explore the excited-state dynamics of both plasmonic and semiconductor materials, with a focus on the underlying mechanisms that govern charge carrier behavior under light excitation. This review provides an overview of the present state of plasmonic and semiconductor photocatalysis, while also highlighting promising directions for future advancements. By exploring synergistic strategies that bridge these two classes of materials, it aims to unlock new pathways for light-driven chemical transformations, ultimately advancing catalytic performance for sustainable energy and environmental applications.