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Due to severe environmental and health risks associated with Cr(VI), there is an urgent need to prioritize the development of new and efficient photocatalysts for its reduction. To solve this issue, three different nanocomposites (NCs) of Zinc oxide (ZnO) with Graphene oxide (GO), i.e. ZnO/@GO were prepared via hydrothermal process, by varying GO concentrations (10, 20, and 30 wt%). The goal is to investigate the impact of GO concentration on the photoreduction of Cr(VI) to Cr (III) in an aqueous system. Various physical properties such as crystallinity, morphology, elemental composition, and optical characteristics of the samples were analyzed using Powder X-ray diffraction (P-XRD), Scanning electron microscopy with Energy dispersive X-ray (SEM–EDX), Ultraviolet–Visible spectroscopy (UV–VIS), Diffuse reflectance spectroscopy, and Photoluminescence spectra, respectively. Photocatalytic reduction of Cr(VI) to Cr (III) was investigated using prepared different ZnO/@GO NCs samples under solar light illumination at room temperature within a pH range of 5.0–6.0. Notably, the highest reduction of 95% was achieved with 10 wt% GO-doped ZnO NCs (ZnO/@10 wt% GO NCs). Kinetic analysis reported the pseudo second-order model and rate constants were found to be 0.349, 0.0123, and 0.001 mol−1L−11 min−1 for the used three different composites, respectively. This data indicates a confirmed decline in the reduction of Cr(VI) to Cr (III) with the increasing concentration of GO in prepared NCs. In last, reduction mechanism was examined which confined the role of ̇OH species in the conversion of Cr(VI) to Cr (III). [ABSTRACT FROM AUTHOR]

This review provides a comprehensive analysis of the rapidly evolving field of solar-driven carbon dioxide (CO2) conversion, focusing on recent developments and future prospects. While significant progress has been made in understanding the fundamental mechanisms of photocatalytic (PC), photoelectrocatalytic, photobiocatalytic, and photothermal CO2 reduction, the efficient and scalable utilization of these technologies remains a challenge. The analysis critically examines the latest advancements in materials and catalysts, including light-harvesting centers, charge transfer interfaces, and catalytically active sites, highlighting their critical role in optimizing efficiency and selectivity. This study examines the recent progress made in PC, photoelectrochemical, and photovoltaic-electrochemical devices, identifying key challenges and opportunities for future research. By highlighting the gap between current research and practical applications, this review aims to provide valuable insights for the development of sustainable and cost-effective technologies for CO2 conversion, contributing to a cleaner and more sustainable energy future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Z-scheme LaOCl-ZnO heterojunction photocatalyst was synthesized by an ultrasound-in-situ deposition technology. • The adsorption equilibrium time of SLZ-1.5 for U(VI) was 130 min, and the adsorption capacity was 905.1 mg/g. • The synergistic effect of adsorption-photoreduction caused the selectivity of SLZ-1.5 for U(VI) to soar to 1.22 × 104 mL/g. • The uranium removal rate of SLZ-1.5 reached 98.6 % after dynamic adsorption outdoors for 26 h. The development of inexpensive and efficient semiconductor catalysts for uranium removal from wastewater via photoreduction remains challenging. Herein, we successfully synthesized Z-scheme heterojunction LaOCl-ZnO-1.5 photocatalyst by ultrasound-assisted in-situ deposition technology followed by immobilization in sodium alginate (SLZ-1.5) by an embedding strategy for the reductive removal of U(VI) from uranium-containing wastewater. The construction of a heterojunction achieves synergistic effects, improving optical response range and photocatalytic efficiency, reducing the loss of photocatalyst through immobilization in the gel structure, and simultaneously solving the difficulty of recycling powder catalysts. SLZ-1.5 demonstrated superior photocatalytic properties for the reduction of U(VI) and rapid reaction kinetics (120 min, 96.1 %) under visible-light irradiation by a xenon lamp. Through the synergistic effect of adsorption and photocatalysis, its optimal removal capacity for U(VI) reached 520.8 mg/g. SLZ-1.5 exhibited great recyclability and excellent selectivity (1.22 × 104 mL/g). In addition, the outstanding performance (98.6 %) of SLZ-1.5 in a dynamic adsorption column under visible-light irradiation validated its potential for practical applications. The photoreduction mechanism indicated that the excellent photocatalytic performance of LaOCl-ZnO-1.5 was enabled by its great light absorption capacity and appropriate bandgap. SLZ-1.5 heterojunction hydrogel is a successful example of a promising adsorption-reduction coupling material that can be applied for the purification and treatment of uranium-containing wastewater. [ABSTRACT FROM AUTHOR]

In this study, a core-shell heterostructure of cuprous sulfide (Cu 2 S) nanoplates and covalent organic polymers (COPs) (Cu 2 S@COP) was constructed in situ by a Cu 2 S-catalyzed azide-alkyne reaction for efficient reduction and rapid removal of U(VI) from uranium mine wastewater. The simple in situ synthesis of heterojunctions through click chemistry reactions can create a tight bond at the interface and evade the laborious process of conventional composites. The different Fermi energy levels of Cu 2 S and COP induce the formation of a built-in electric field within the core-shell heterojunction, and the photogenerated charge transfer from the COP to Cu 2 S nanoplate results in a substantial boost in the efficiency of the photocatalytic reduction of U(VI). The Cu 2 S@COP heterojunction demonstrates a high U(VI) removal capacity of 1164.6 mg g -1 without the need of a sacrificial agent, which is 2.08 times higher than Cu 2 S nanoplates, 3.02 times higher than COP, and better than most other previous heterostructures. The present photocatalytic method involves good specificity and achieves a high U(VI) removal efficiency of 85.9% from uranium mine wastewater. The in situ preparation of the Cu 2 S@COP core-shell heterojunction via click chemistry provides a new design concept for composite construction and presents a novel strategy to modulate the photocatalytic activity for contaminant management.

We report herein two families of porous coordination clusters (PCCs) with 216 nuclearity (M 120 RE 96 or PCC-216MR) and 300 nuclearity (Co 144 Gd 156 or PCC-300CG). For the first family M could be either nickel or cobalt, and RE = Pr, Nd, Sm, Eu, and Gd; while the latter features the highest nuclearity of transition-rare earth metal clusters. Characterized by their cube-like, hollow structures, these clusters exhibit the ability to absorb N 2 and CO 2 . Besides, these clusters can be dissolved in both aqueous and acetonitrile/methanol solutions, and capable of acting as homogeneous catalysts for converting CO 2 to CO under visible light. The gadolinium analogues of these clusters all show turnover numbers over 10000 and turnover frequencies over 1 s -1 . In particular, the nickel based bimetallic cluster (PCC-216NG) demonstrates nearly 100 % selectivity for the reduction product, which may open a new direction for the design and development of PCCs based catalysts., (© 2025 Wiley-VCH GmbH.)

Visible-light-driven photocatalytic uranium extraction based covalent organic frameworks (COFs) are green and sustainable, but their performance is severely restricted by a strong exciton effect. Herein, inspired by the physiology of cardiac pacing, a novel fluorine-based COF (PyF-DaS-COF) with a biomimetic electronic pump has been fabricated and used for the photocatalytic extraction of uranium. Both experimental and theoretical calculations confirm that strongly electronegative fluorine plays a crucial role in exciton dissociation and charge transfer. The enhanced electron push-pull effect increases the intrinsic separation driving force of charge separation. Furthermore, fluorine substitution thermodynamically favors the generation of the crucial *OOH intermediate in the uranium reduction reaction. As a result, the PyF-DaS-COF achieves a record k value ( T = 293 K) of 0.082 min -1 with an extraction capacity of 991.5 mg g -1 . Importantly, PyF-DaS-COF achieves a removal rate of over 99% in real uranium-containing wastewater. The current work provides unique insights into designing novel and effective COFs for controlling radioactive contamination.