High efficiency and durable non-noble-metal electrocatalysts for the hydrogen evolution reaction (HER) are essential for large-scale green hydrogen production. In this work, a trimetallic polyoxometalate (POM) precursor H₂[Co(NH₃)₆]₂[CeMo₁₂O₄₂] (Co₂CeMo₁₂) was synthesized via the self-assembly of POM. Subsequently, Co and Ce co-doped MoS₂ electrocatalyst (Co,Ce-MoS₂@CC) was in situ grown on carbon cloth (CC) through a one-step hydrothermal sulfidation process. This precursor strategy effectively avoids phase separation and interfacial mismatch, which are the two major drawbacks of conventional doping routes. Experimental results combined with density functional theory (DFT) calculations demonstrate that Ce³⁺/Ce⁴⁺ redox pairs modulate the interfacial charge distribution of the catalyst. The doped Co species serve as electron acceptors to balance the electron enrichment induced by Ce, thereby optimizing the HER kinetics and the adsorption/desorption free energy of reaction intermediates. In 1.0 M KOH, the optimized Co,Ce-MoS₂@CC requires an overpotential of only 58 mV to achieve 10 mA cm^-2, while in 0.5 M H₂SO₄, 118 mV is needed. It maintains stable electrocatalysis over 72 h at a high current density of 100 mA cm^-2 in both alkaline and acidic electrolytes. This work proposes a POM precursor-mediated Co-Ce co-doping strategy that exhibits potential for scalable fabrication of high-performance MoS₂-based non-noble-metal electrocatalysts, suitable for HER applications.

Polyoxometalates (POMs) are ideal preassembled platforms for constructing transition metal catalysts because they are rich in oxygen and transition metal elements. In contrast to traditional methods for preparing V₂O₅/MoS₂ composite catalysts, the method proposed in this study leverages the selective preference of vanadium for oxygen vs. sulfur. A MoS₂-based electrocatalyst composited with a small amount of V₂O₅ was constructed in situ on a carbon cloth via a one-pot hydrothermal method using a Lindqvist-type POM, i.e., (C₁₆H₃₆N)₂ Mo₃V₃O₁₆(OCH₂)₃CCH₂CH₃ (Mo₃V₃), as a precursor. This catalyst was used for efficient electrocatalytic hydrogen evolution reaction. The experimental results reveal that the introduction of a small amount of V₂O₅ considerably increases the electrochemically active surface area of the catalyst, effectively enhancing the catalytic performance of the material. This study provides a new design strategy and synthetic pathway for precise construction of high-performance composite electrocatalysts based on POM precursors.

Iridium (Ir)-based nanomaterials are promising electrocatalysts for water splitting, and to alleviate their costs as well as improve the performances are always important tasks. Polyoxometalates (POMs) composed of abundant metal, oxygen, and heteroatoms are nanoclusters with defined structures. Benefitting from the inherent advantages of POMs, highly dispersive and “unprotected” Ir nanoparticles originating from Ir-based colloid solution were successfully anchored on POM-derived WO₃/rGO nanocomposites for the first time. Interestingly, the obtained hybrid material Ir/WO_x/rGO delivered improved electrocatalytic performance for water splitting, which is attributed to the addition of only quite small amount of POM derivatives. This work is also the first proof that POM can be employed as precursor to construct metal oxides to support Ir catalysts, providing a new vision for the design of advanced multi-metal electrocatalysts.

An emerging method for effectively improving the catalytic activity of metal oxide hybrids involves the creation of metal oxide interfaces for facilitating the activation of reagents. Here, we demonstrate that bilayer vesicles formed from a hexavanadate cluster functionalized with two alkyl chains are highly efficient catalysts for the oxidation of 3, 3′, 5, 5′-tetramethylbenzidine (TMB) with H₂O₂ at room temperature, a widely used model reaction mimicking the activity of peroxidase in biological catalytic oxidation processes. Driven by hydrophobic interactions, the double-tailed hexavanadate-headed amphiphiles can self-assemble into bilayer vesicles and create hydrophobic domains that segregate the TMB chromogenic substrate. The reaction of TMB with H₂O₂ takes place at the interface of the hydrophilic and hydrophobic domains, where the reagents also make contact with the catalytic hexavanadate clusters, and it is approximately two times more efficient compared with the reactions carried out with the corresponding unassembled systems. Moreover, the assembled vesicular system possesses affinity for TMB comparable to that of reported noble metal mimic nanomaterials, as well as a higher maximum reaction rate.