Near infrared energy remains untapped toward the maneuvering of entire solar spectrum harvesting for fulfilling the nuts and bolts of solar hydrogen production. We report the use of Au@Cu₇S₄ yolk@shell nanocrystals as dual-plasmonic photocatalysts to achieve remarkable hydrogen production under visible and near infrared illumination. Ultrafast spectroscopic data reveal the prevalence of long-lived charge separation states for Au@Cu₇S₄ under both visible and near infrared excitation. Combined with the advantageous features of yolk@shell nanostructures, Au@Cu₇S₄ achieves a peak quantum yield of 9.4% at 500 nm and a record-breaking quantum yield of 7.3% at 2200 nm for hydrogen production in the absence of additional co-catalysts. The design of a sustainable visible- and near infrared-responsive photocatalytic system is expected to inspire further widespread applications in solar fuel generation. In this work, the feasibility of exploiting the localized surface plasmon resonance property of self-doped, nonstoichiometric semiconductor nanocrystals for the realization of wide-spectrum-driven photocatalysis is highlighted.

Density‐functional theory (DFT) is pivotal in the advancement of photocatalysis and photoelectrocatalysis. Its capability to explore electronic structures of materials contributes significantly to clarifying the mechanisms of photocatalytic (PC) and photoelectrocatalytic (PEC) processes. DFT calculations enable a deeper understanding of how these processes work at a molecular level, which is essential for designing versatile photocatalysts and photoelectrodes and optimizing reaction pathways. In this perspective, key PC and PEC applications, such as H ₂ production, CO ₂ reduction, dye degradation, and N ₂ reduction, where DFT is instrumental in optimizing materials designs and reaction pathways, are highlighted. Exploration on the synergy between experimental research and DFT calculations is highlighted, which is crucial for the development of efficient and environmentally friendly energy solutions. The discussion further extends to challenges and future directions, emphasizing the need for incorporating factors, including discrepancy in scale, light illumination, electrolyte presence, and applied bias, into DFT calculations, to achieve a more comprehensive understanding of PC and PEC systems. In this perspective, it is aimed to provide a holistic view of the current state and potential advancements in photocatalyst and photoelectrode modeling, thereby guiding future research toward more effective and sustainable energy and chemical production processes in PC and PEC systems.