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Over the past two decades, the radiosynthesis of metallic nanoclusters (MNCs) using γ-irradiation (γ-radiosynthesis) has presented a wealth of opportunities for the application of nanomaterials in areas such as medicine, energy, catalysis, and sensors. Unlike conventional methods, this technique provides fully reduced and highly stable MNCs that are free from by-products or impurities. γ-Radiosynthesis has thus proven to be a clean and green approach for bulk fabrication of MNCs with tunable particle sizes and morphologies. More recently, the in-situ decoration of MNCs on support materials using γ-irradiation has attracted much attention due to the synergistic effect between MNCs and the underlying support. In this review, we discuss the current state of research into the mechanisms underlying the γ-radiosynthesis of supported and unsupported mono- and bi-metallic nanoclusters and summarize the use of MNCs in catalysis, sensing, biomedicine, and energy applications.

Electrocatalytic water splitting is a very promising and sustainable approach for generating hydrogen as a clean carbon-free fuel. To develop an efficient electrocatalyst for water splitting, the overpotential for this reaction must be minimized by using a capable electrocatalyst that can support the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In this study, we prepared a unique core–shell structure, Co-metal–organic framework (MOF) derived cobalt diselenide laminated with molybdenum diselenide (MOF-CoSe2@MoSe2) and assessed its performance as a bifunctional electrocatalyst for the HER and OER in alkaline media. The CC/MOF-CoSe2@MoSe2 core–shell structure fabricated directly on a flexible carbon cloth substrate demonstrated low overpotentials (η10) of 109.87 and 183.81 mV for the HER and OER, respectively, and a low voltage of 1.53 V for overall water splitting activity with an electrolyzer cell with symmetric CC/MOF-CoSe2@MoSe2 electrodes. The developed CC/MOF-CoSe2@MoSe2 catalyst had excellent stability over 24 h for OER, HER, and overall water splitting activity. These results suggest that lamination of MOF with a transition metal dichalcogenide is an effective route for developing the highly efficient and sustainable bifunctional electrocatalyst for overall water splitting activity.

Two-dimensional (2D) titanium carbide (Ti3C2Tx), MXene, is an attractive pseudocapacitive electrode material that exhibits its highest capacitance at a negative potential in an aqueous protic (H2SO4) electrolyte. Developing hybrid supercapacitors (HSCs) using diverse cathode materials is the best way to identify a material with high energy density in aqueous electrolytes. However, it is difficult to find redox-active positive cathode materials that are suitable for use with MXene in an H2SO4 electrolyte. Here, 2D nanocomposite of reduced graphene oxide (rGO) decorated with phosphomolybdic acid (PMo12) polyoxometalates (POMs) are reported as promising cathode materials suitable for use against an MXene anode. The complementary potential window of MXene and rGO-POMs along with the redox activity and 2D nanostructured features of these materials can significantly enhance the electrochemical properties of HSC cell. An all-redox active HSC cell with rGO-POM cathode and MXene anode can deliver a maximum specific energy and power of 50.46 Wh/kg and 7000 W/kg, respectively, with capacitance retention of 87.12 % over 10,000 cycles and superb energy and coulombic efficiency over all applied current densities. These results suggest that the rGO-POMs cathode can be potentially coupled with an MXene anode in a protic electrolyte to enhance the electrochemical parameters of the HSC cells.

Here, we designed and synthesized a recoverable multifunctional adsorbent using a microfluidic reaction system and evaluated the removal performance of the smart adsorbent toward radioactive cesium as a model sample. Prussian blue-laden magnetic micro-adsorbents (PB-MNPs-MAs) with uniform morphology and monodispersity were generated via two-step sequential procedures using a glass capillary microfluidic system, followed by chemical co-precipitation with a high production rate. The cesium removal efficacy of the PB-MNPs-MAs was analyzed based on Langmuir and Freundlich isotherms by controlling adsorption parameters such as adsorbent size, initial cesium concentration, and contact time. The adsorption isotherm of the PB-MNPs-MAs was better fitted to the Langmuir model with a maximum cesium adsorption capacity of 58.73 mg g−1, which was 40% higher than that of macro-adsorbents in a dynamic magnetic field. This result can be attributed to their large specific area, which increased the kinetic rate of cesium adsorption and achieved saturation within 20 min. Additionally, the PB-MNPs-MAs were recovered from wastewater within 5 s under a static magnetic field, indicating their great potential for magnetic actuation. We believe that our PB-MNPs-MAs can encapsulate nano-functional adsorbents and prevent actuation, making them promising for environmental remediation and especially for removal of radionuclides.

Heterostructure-based photocatalysis offers significant potential for developing ultraviolet–visible (UV–Vis) to near-infrared (NIR) light-responsive catalysts with abundant beneficial physicochemical properties to boost environmental remediation upon solar-light irradiation. In this study, for the first time a novel ternary heterostructure photocatalysts containing Bi2S3@CdS@RGO (BCG) were rationally constructed using the hydrothermal approach. The resultant ternary composite with 5 wt% of CdS and 20 wt% of reduced graphene oxide (RGO) contents (BCG-5) was adopted as an optimal sample for photo-reduction of Cr(VI) under simulated solar-light irradiation. The apparent rate constant of the photo-reduction process over BCG-5 was ~ 13, 4, and 3 times higher than those of Bi2S3, CdS, and BC-5, respectively, within 150 min. The enhanced photocatalytic activity of ternary composite could be linked predominantly to the formation of heterostructural, synergistic behavior between the components, hierarchical morphology, the formation of n-n type high-low junctions, efficient interfacial charge-transfer capability, large specific surface area, full-spectrum light-absorption, and outstanding photo-stability. Electron spin resonance and reactive radical-scavenging results demonstrated that the hydroxyl and superoxide active species were primarily responsible for Cr(VI) removal. Furthermore, the photocatalytic activity of BCG-5, as an optimal sample, was further assessed regarding the photocatalytic production of H2O2, with 1.37 and 15.14 times higher efficiency than binary and bare samples, respectively. Assisted by the density functional theory calculations, ultraviolet photoelectron spectroscopy analyses, the charge-carriers pathway and possible photocatalytic mechanism were systematically discussed in S-scheme heterojunction. We expect that our findings will open new horizons for significant applications of bismuth-rich-based heterostructures under both visible- and NIR-light irradiation to address environmental and energy issues.

MXenes have very recently emerged as an intriguing family of graphene-like two-dimensional (2D) layer-structured transition metal carbides and/or nitrides with a high specific surface area, a large interlayer spacing, hydrophilicity, and abundant highly active surface sites, and they have found a niche in environmental remediation, as materials capable of efficiently removing and sequestering heavy metals, dyes, and radioactive nuclides. With exceptional surface tunable chemical compatibility and compositional flexibility, MXenes are resistant to radiation-induced damage and show high chemical compatibility and excellent thermal stability. They are thought to have the potential to serve as ideal adsorbents for a plethora of radionuclides such as uranium (238U), thorium (232Th), cesium (137Cs), and strontium (90Sr) with respect to technology and the economy. In this article, we comprehensively review state-of-the-art research progress on and the promising potential of MXenes as an adsorbent for the removal of radioactive nuclides from the environment. First, we discuss the structure, synthesis, intercalation/delamination and properties of MXenes. Subsequently, we emphasize their radionuclide removal applications. Finally, we present an outlook on the current challenges in the use of MXene materials for the adsorptive remediation of radionuclides and outline future opportunities for these materials. This article presents a timely and systematic review of MXenes as efficient and cost-effective radionuclide adsorbents. Furthermore, it highlights the main challenges in their use for environmental remediation and provides possible research directions.

Inorganic perovskite nanocrystals (NCs) of cesium lead mixed halides (CsPb(X/Y)3, X = Br, Y = Cl and I) are promising optical materials for developing the high-performance photonic devices. Traditionally, anion-exchange reaction in perovskite halide NCs provides a simple substitutional way to tune the composition and emitting color with good luminescence properties in the human eye detectable visible spectral regions. However, prior synthetic procedures of perovskite NCs have employed conventional flask-based reactions which limit the fine control of perovskite NCs because of extremely fast anion-exchange kinetics. To overcome such problems, we demonstrate a droplet-based microfluidic system with simple, fast, and high-throughput parametric screening for the synthesis of perovskite NCs. By using the customized microfluidic operational system consisting of serially integrated two microfluidic reactors and heating block, we have successfully synthesized CsPbX3 perovskite NCs. In addition, we can finely control the anion-exchange reaction which can generate the formation of CsPb(X/Y)3 perovskite NCs with a wide range of visible spectrum (410–630 nm). Ultimately, we have established their potential applications in the development of solid-state lighting-based flexible display systems.

In microalgae-based biorefinement, the integration of harvesting and lipid extraction steps could reduce the costs of downstream processes. One potential of integrated methods, microalgae harvesting by aminoclay-conjugated TiO2 has been considered. Therein, aminoclay plays an efficient role in microalgae flocculation and direct cell disruption by TiO2 photocatalytic performance under UV-light irradiation. In the present study, two TiO2 photocatalysts, a commercial anatase/rutile bicrystalline (of ∼5 nm diameter) and anatase/brookite bicrystalline (of ∼3.5 nm diameter) by sol–gel reaction at room temperature, were distributed uniformly onto an aminoclay matrix by ultrasound-irradiated TiO2 particles, resulting in aminoclay-conjugated TiO2 composites. Within 10 min, the injection of aminoclay-conjugated TiO2 into the prepared 1.5 g/L-concentration microalgal feedstocks produced an ∼85% harvesting efficiency for oleaginous Chlorella sp. KR-1. Subsequently, the harvested wet-microalgae biomass was UV-irradiated at 365 nm for 3 h, thereby effecting the disruption of ∼95% of cells.

We demonstrate the hollow triple-shelled SiO 2 /TiO 2 /polypyrrole (Ppy) nanospheres (NSs), which are readily synthesized through the hard templating method and sequential vapor deposition polymerization (VDP), for application in lithium ion battery (LIB) anodes. The resultant NSs with a hetero-composition show a uniform hollow spherical nanomorphology consisting of SiO 2 , TiO 2 , and Ppy layers, as verified by the Si, Ti, C, and O signals of the STEM images. The hollow SiO 2 /TiO 2 /Ppy NSs have about a threefold higher capacity of 433 mA h/g compared to 147 mA h/g of TiO 2 at a specific current of 44 mA/g, which is close to the theoretical value of TiO 2 . In particular, the hollow triple-shelled NSs exhibit good rate (76% capacitance retention in the range of 44−440 mA/g) and cyclic (98% in the fifty cycles) performances due to the reversible redox reaction occurring on the Ppy outer shell. The enhanced performance of the SiO 2 /TiO 2 /Ppy NSs is attributed to the synergistic effect of the 0D nanostructure and hetero-composition.