Efficient electron-hole separation and carrier utilization are key factors in photocatalytic systems. Here, we use a metal-organic framework (NH2-UiO-66) modified with inner platinum nanoparticles and outer cadmium sulfide (CdS) nanoparticles to construct the ternary composite Pt@NH2-UiO-66/CdS, which has a spatially separated, hierarchical structure for enhanced visible-light-driven hydrogen evolution. Relative to pure NH2-UiO-66, Pt@NH2-UiO-66, and NH2-UiO-66/CdS samples, the Pt@NH2-UiO-66/CdS composite exhibits much higher hydrogen yields with an apparent quantum efficiency of 40.3% at 400 nm irradiation and stability over the most MOF-based photocatalysts. Transient absorption measurements reveal spatial charge-separation dynamics in the composites. The catalyst’s high activity and durability are attributed to charge separation following an efficient photogenerated hole-transfer band-trap pathway. This work holds promise for enhanced MOF-based photocatalysis using efficient hole-transfer routes.

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The effective separation of photogenerated electrons and holes is the key to improve photocatalytic activity in hydrogen evolution reaction (HER). However, the mechanism of photoinduced charge transfer between the cocatalyst and the semiconducting heterojunction in a single nanocrystal is vague at present. Herein, the relationships between the crafted cocatalyst and the constructed semiconducting heterojunction in a single nanocrystal were verified. Manipulating these relationships will improve the performance of visible light-driven hydrogen evolution. As a model, we used CuInS 2 (CIS) nanocrystals (NCs) modified by the cocatalyst platinum (Pt) NCs and the semiconductor cadmium sulfide (CdS), forming the ternary heterostructured NCs (HNCs). Under visible light irradiation, the photocatalytic activity in hydrogen evolution of Pt-CIS/CdS HNCs is 6.38 and 1.76 times higher than those of pristine CIS NCs and CIS/CdS HNCs, respectively. Transient absorption measurements certified that the high photocatalytic activity in the HER was attributed to the photoinduced electron transfer from the defect-mediated trap state in CIS to the cocatalyst Pt, which was superior to the direct Z-scheme heterojunction between CIS and CdS. This research paves a route for the design of a suitable cocatalyst and the formation of heterostructured semiconducting NCs for boosting the photocatalytic activity in solar energy conversion.

Combining metal nanoparticles (NPs) featured with localized surface plasmon resonance (LSPR) with metal–organic framework (MOF)‐based photocatalysts is a novel means for achieving efficient separation of electron–hole pairs. Herein, the Au@NH2‐UiO‐66/CdS composites are successfully synthesized by encapsulating Au NPs with LSPR into the NH2‐UiO‐66 nanocage, further growing CdS NPs on the surface of the NH2‐UiO‐66, which exhibits higher photocatalytic activity in hydrogen evolution reaction under visible‐light irradiation than that of NH2‐UiO‐66/CdS and CdS, respectively. Transient absorption measurements reveal that MOF is not only a transit station for electrons generated from CdS to Au, but also a receiver for hot electrons generated from plasmonic Au in Au@MOF/CdS composites. Thus, the LSPR‐induced hot electron transfer from Au NPs is an important manifestation to prolong the carrier lifetime and enhance the photocatalytic performance. This work provides insights into investigating the photoinduced carrier dynamics of nanomaterials with LSPR effects for enhancing the MOF‐based photocatalytic performance.

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