Heavy metal ions pose persistent threats to environmental safety and public health, creating an urgent demand for analytical platforms capable of sensitive, reliable, and visual detection. Herein, a polyoxometalate-functionalized covalent organic framework composite (Ru-POCOF) is developed as a trimodal sensing platform integrating fluorescence (FL), UV–vis absorption, and electrochemiluminescence (ECL) for the detection of Cu²⁺, Fe³⁺, and Hg²⁺. In this architecture, the Ru-COOH (Ru[dcbpy]₃²⁺) complex serves as the photoelectrochemical signal center, while aminated Dawson-type P₂W₁₈ clusters are incorporated into an ordered COF scaffold, providing abundant coordination sites and efficient charge-transfer pathways. Benefiting from this synergistic structure, Ru-POCOF exhibits distinct ion-dependent responses across multiple channels: Cu²⁺ and Fe³⁺ induce significant quenching of FL and UV signals accompanied by visible luminescence changes under UV irradiation, whereas Hg²⁺ is sensitively detected through ECL attenuation. Furthermore, machine learning–assisted analysis of spectral features enables accurate discrimination between Fe³⁺ and Cu²⁺, significantly enhancing analytical reliability in complex matrices. In addition to sensing capability, Ru-POCOF demonstrates rapid adsorption toward Fe³⁺ with a removal efficiency exceeding 60% within 20 min. Reliable detection is validated in tap water, rat serum, and Codonopsis pilosula extracts. Overall, this multifunctional POM–COF hybrid integrates multimodal sensing, visual detection, intelligent analysis, and efficient adsorption, providing a versatile strategy for monitoring trace heavy metal ions in complex systems.

The functionalization of C−H bonds is critical in organic syntheses. However, their direct functionalization under mild conditions is complicated by their inherent inertness. To address this challenge, decatungstates (W₁₀O₃₂⁴⁻), as versatile, inexpensive, and easily accessible hydrogen-atom transfer (HAT) photocatalysts, have emerged as powerful catalysts that can activate inert C−H bonds under ultraviolet irradiation to generate carbon-centered radicals for constructing C−C, C−N, C−S, and C−F bonds. This review highlights recent advances in W₁₀O₃₂⁴⁻-based photocatalysts and their applications in organic transformations. Overall, this article explores various W₁₀O₃₂⁴⁻-photocatalyzed organic transformations. In addition to summarizing the reported literatures, it critically discusses the current challenges and offers insights for future developments in this promising research field.

The photocatalytic oxidation of 1-phenylethanol coupling with hydrogen evolution represents a promising strategy for the full utilization of the photogenerated electrons and holes to accomplish the maximum conversion of solar energy into chemical energy. To date, however, the controllable of reaction path and product distribution has yet not to be unrevealed. Herein, we report an efficient coupled catalytic system composed of ZnIn₂S₄/WO₃ S-scheme heterojunction and Ni-containing polyoxometalate ([Ni₄(H₂O)₂(PW₉O₃₄)₂]¹⁰⁻ (Ni₄P₂)), which exhibited excellent photocatalytic activities towards the oxidation valorization of 1-phenylethanol coupling with hydrogen evolution. The addition of Ni₄P₂ can efficiently control the product distribution. Specifically, 1-phenylethanol was preferentially converted to pinacol (86.0% selectivity) via C–C coupling over ZnIn₂S₄/WO₃ S-scheme heterojunction accompanied by hydrogen production (202.4 μmol), whereas it would be converted to acetophenone (93.8% selectivity) by photogenerated holes with concomitant hydrogen formation (183.1 μmol) over the coupled Ni₄P₂/ZnIn₂S₄/WO₃ catalytic system. Mechanism studies revealed that the hydrogen evolution cocatalyst Ni₄P₂, with its excellent electron storage capacity, can compete with the oxidation product acetophenone for electrons, and thus its addition can significantly inhibit the reduction of acetophenone, resulting in the inability to generate the coupling product pinacol.

In terms of photoelectrochemical (PEC) hydrogen evolution, substantial challenge still remains regarding the controllable fabrication of quantum dots (QDs)-sensitized photocathodes with enhanced visible-light absorption, efficient charge carrier separation, and directional migration at the electrode interface. In this work, the CdTe/CdSe QDs-sensitized photocathodes were delicately constructed on p-type NiO-coated indium tin oxide (ITO) electrodes by spin-coating approach. The resulting co-sensitized photocathode exhibits a favorable pseudo-Type Ⅱ energetic band alignment that combines the advantages of strong light absorption of constituent QDs as well as the effective and oriented charge separation and migration. Upon green LED light illumination, the photogenerated electrons could be effectively transferred to a tetra-nickel-substituted polyoxometalate catalyst for hydrogen production while photogenerated holes will be scavenged at the NiO/ITO electrode. Under minimally optimized conditions, the pseudo-Type Ⅱ CdTe/CdSe-sensitized photocathode yields a photocurrent density of over 100 μA/cm² and a Faradaic efficiency of ~ 100%, which is among one of the most efficient QDs-based photocathode systems coupling with Ni-substituted polyoxometalate catalyst for photoelectrochemical hydrogen generation.