Dmitry Aldakov

Lead-free halide nanocrystals have emerged as a sustainable alternative to lead halide perovskites materials; owing to their strong light absorption, low-toxicity and optimal bandgap for visible light driven applications. Herein, we aim to broaden the application of benzoyl bromide as Br-source in a modified hot-injection protocol for the synthesis of colloidal Cs3Bi2Br9 nanocrystals (cCBB NCs). Moreover, for comparative purposes CBB NCs incorporated into the mesoporous silica SBA-15 were prepared. The photocatalytic performance of both systems was evaluated using the degradation of cationic organic dyes, such as methylene blue (MB) and rhodamine B (RhB), as model reactions. Notably, complete dye degradation was achieved at very short irradiation times, ca. 300 s for RhB in both colloidal and supported systems, the fastest rate reported up to now, mediated predominantly by anion superoxide as selective oxidizing agent. However, in the case of MB, its strong binding to CBB surface and incorporation into the SBA-15 pores limit the photodegradation process, which is proposed to occur via direct charge transfer and anion superoxide formation. This work highlights the importance of the CBB synthetic procedure and the dye adsorption behavior on the NCs surface or into the silica pores in determining the photocatalytic activity of bismuth halide NCs.

Owing to its large earth crust abundance, long‐term stability, and high intrinsic conductivity, molybdenum sulfide (MoS ₂ ) has emerged as a promising hydrogen evolution reaction (HER) electrocatalyst. However, the key challenge for the HER is to activate the broader inert basal plane of MoS ₂ to increase the density of active sites and maximize catalytic activity. Heteroatom doping can open sulfur vacancies and produce defects that create additional active sites. Herein, we demonstrate for the first time a trimetallic W‐ and V‐doped MoS ₂ nanocatalyst synthesized with different doping ratios by a green synthesis route. W and V dopants induce a synergistic effect on the nanoflower‐shaped MoS ₂ structure, increasing the density of defects in the MoS ₂ 2D layer as well as in layer stacking. We show a correlation between defect density, increased number of exposed edge sites, enhanced active surface area, and better electrocatalytic activity in this series of materials. The best W and V codoped MoS ₂ electrocatalyst exhibits an overpotential of 186 mV at 10 mA·cm ⁻² for HER, which is 1.2 times lower than that of pristine MoS ₂ , and delivers hydrogen production with 100% Faradaic efficiency in continuous operation for over 16 h.

Ternary quantum dots (TQDs) are promising cadmium-free nanomaterials for optoelectronic and biomedical applications; however, systematic comparisons among AgInS2 (AIS), CuInS2 (CIS), and ZnIn2S4 (ZIS) quantum dots remain limited because these materials are typically investigated using different synthetic protocols and characterization methodologies. Herein, we present a systematic comparative study of aqueously synthesized AIS, CIS, and ZIS quantum dots, enabling direct comparison of their optical, electrochemical, surface, and biological properties within a unified comparative framework. The nanocrystals exhibited similar sizes (4–6 nm), ensuring that the observed differences primarily reflected composition. Combined optical and electrochemical analyses revealed consistent trends in bandgap energies that were in good agreement with Mulliken electronegativity-based predictions. Despite their structural similarity, AIS showed long lifetimes and moderate emission efficiency, CIS exhibits suppressed photoluminescence due to dominant nonradiative recombination, whereas ZIS exhibited fast recombination dynamics associated with surface-dominated states. X-ray photoelectron spectroscopy established a direct relationship between composition, defect states, and electronic structure, while all QDs exhibited high cell viability (>90%), confirming their cytocompatibility. Overall, this unified comparative approach demonstrates that cation identity governs band alignment, recombination pathways, and cytocompatibility, providing practical guidance for the rational design of cadmium-free quantum dots for photocatalytic, optoelectronic, and biomedical applications.

The electrocatalytic reduction of CO ₂ is a promising technology for a versatile conversion of CO ₂ emissions into a reactive feedstock, in a process compatible with intermittent renewable power supply. It requires first efficient catalysts with low over potential and high selectivity. Second, the setup must allow for an efficient use of the CO ₂ feed, toward a complete conversion. Third, catalyst and electrolytic parameters have to be optimized for long‐term stability. Here, we implement Ag as a selective catalyst for CO ₂ reduction into CO, shaped into silver nanowires to ensure both a large electrochemical surface area and a high conductivity. The sprayed silver nanowire electrodes are tested i) in a flow cell for electrochemical characterization in three‐electrode configuration, and ii) in a zero‐gap electrolyzer offering high throughput and tightness for accurate Faradaic efficiency FE _CO measurements and relevant current density. They demonstrate state‐of‐the‐art catalytic efficiency from –1.0 V _RHE , and a stable FE _CO exceeding 90% over 8 h. Surprisingly, this long‐term stable electrocatalytic performance contrasted with the morphological changes in the silver nanowire electrode observed early in CO ₂ RR, even at low current density. We show that these structural changes correlate with the partial removal of the polymer capping layer around the silver nanowires.

PbS quantum dots (QDs) show great promise as active materials for near‐infrared photodetectors. Halide perovskites are known to efficiently passivate the surface of PbS; however, there is currently no model to explain the passivation of large QDs by perovskites, which is key to controlling their stability. In this study, we present a systematic analysis of the ligand structure of methylammonium lead iodide (MAPI)‐passivated 4‐nm PbS QDs. Through a combination of FTIR, XPS, SEM, NMR, DFT, and other techniques, we propose a comprehensive ligand model, showing that the (100) PbS facets are passivated by a MAPI monolayer and the (111) facets by a PbI ₂ monolayer. We also demonstrate that this passivation approach can be extended to other perovskite compositions. Finally, we present a proof‐of‐principle photodetector device demonstrating promising performance. Precise elucidation of the ligand structure will help optimizing the surface passivation of PbS QDs, leading to more efficient and stable photodetectors.

A synthesis method for preparing Ga₂S₃ capped AgGaS₂ quantum dots exhibiting narrow blue emission is provided along with the in-depth study of their optical properties including time-resolved and temperature-dependent photoluminescence spectroscopy.

Colloidal InSb quantum dots (QDs) are a potential alternative to toxic Pb‐ and Hg‐chalcogenide QDs for covering the technologically important near‐infrared/shortwave infrared (NIR/SWIR) spectral range. However, appropriate Sb precursors are scarce and obtaining narrow size distributions is challenging. Tris(dimethylamido)antimony (Sb(NMe₂)₃) is an appealing choice due to its commercial availability and non‐pyrophoric character but implies the reduction of antimony from the +3 to the required –3 state. In reported works, strong reducing agents such as lithium triethylborohydride are used, which lead to the fast co‐reduction of both Sb³⁺ and In³⁺. The downsides of this approach are reproducibility issues and the risk of forming metal nanoparticles due to the different reduction kinetics of Sb³⁺ and In³⁺. Here, indium(I) halides are explored as simultaneous indium source and mild reducing agent for the antimony precursor. The wavelength of the excitonic absorption peak of the phase‐pure InSb QDs obtained with this approach can be tuned from 630 to 1890 nm, which corresponds to a size range of ≈2–7 nm. The synthesis can also be conducted in a heat‐up manner, which facilitates the scale‐up and paves the way for the use of InSb QDs in applications such as NIR/SWIR photodetectors, cameras, biological imaging, and telecommunications.

Electrode-confined molecular catalysts are promising systems to enable the efficient conversion of CO₂ to useful products. Here, we describe the development of an original molecular cathode for CO₂ reduction to CO based on the noncovalent integration of a tetraazamacrocyclic Co complex to a carbon nanotube-based matrix. Aqueous electrochemical characterization of the modified electrode allowed for clear observation of a change of redox behavior of the Co center as surface concentration was tuned, highlighting the impact of the catalyst microenvironment on its redox properties. The molecular cathode enabled efficient CO₂-to-CO conversion in fully aqueous conditions, giving rise to a turnover number (TON_CO) of up to 20 × 10³ after 2 h of constant electrolysis at a mild overpotential (η = 450 mV) and with a faradaic efficiency for CO of about 95%. Post operando measurements using electrochemical techniques, inductively coupled plasma, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy characterization of the films demonstrated that the catalysis remained of molecular nature, making this Co-based electrode a new promising alternative for molecular electrocatalytic conversion of CO₂-to-CO in fully aqueous media.