Innovative hydrothermal technique in efficient disengagement of waste solar panels.

The delamination of layers of waste solar panels remains a major challenge due to the lack of effective solutions for removing the adhesive between layers. In this study, a novel efficient method for disengagement of glass from the rest of the module is introduced, in which only water is used under high pressure (<3 MPa) and relatively low temperatures (230-250 °C) in a hydrothermal reactor, allowing for facile separation of the glass from the interlayer. The other layers of the module can also easily be peeled apart in subsequent processes. The separated glass is free of metals and polymers that can be utilized directly for further applications. The benefits of this method include no use of chemicals, preservation of the recovered materials' quality (i.e., interlayers, Si sheet, and glass), relatively low-temperature operation, no hazardous gas generation, and reduced energy consumption. A pilot scale design of the method has been proposed for processing a full panel, demonstrating its industrial viability.

Liquid Metal Doping Induced Asymmetry in Two-Dimensional Metal Oxides.

The emergence of ferroelectricity in two-dimensional (2D) metal oxides is a topic of significant technological interest; however, many 2D metal oxides lack intrinsic ferroelectric properties. Therefore, introducing asymmetry provides access to a broader range of 2D materials within the ferroelectric family. Here, the generation of asymmetry in 2D SnO by doping the material with Hf0.5 Zr0.5 O2 (HZO) is demonstrated. A liquid metal process as a doping strategy for the preparation of 2D HZO-doped SnO with robust ferroelectric characteristics is implemented. This technology takes advantage of the selective interface enrichment of molten Sn with HZO crystallites. Molecular dynamics simulations indicate a strong tendency of Hf and Zr atoms to migrate toward the surface of liquid metal and embed themselves within the growing oxide layer in the form of HZO. Thus, the liquid metal-based harvesting/doping technique is a feasible approach devised for producing novel 2D metal oxides with induced ferroelectric properties, represents a significant development for the prospects of random-access memories.

Controllable design of defect-rich hybrid iron oxide nanostructures on mesoporous carbon-based scaffold for pseudocapacitive applications.

The controllable design of functional nanostructures for energy and environmental applications represents a critical yet challenging technology. The existing fabrication strategies focus mainly on increasing the number of accessible active sites. However, these techniques generally necessitate complex chemical agents and suffer from limited experimental conditions delivering high costs, low yields, and poor reproducibility. The present work reports a new strategy for controllable synthesis of a hybrid system including mixed iron oxide nanostructures enriched with non-stoichiometric Fe21.34O32 and Fe3+[Fe5/33+□1/32+]O4 phases, which possess a high concentration of oxygen and Fe2+ vacancies, and a mesoporous carbon-based scaffold (MCS), which was dervied from coffee residues, with graphitic surface and perforated architecture. The nanoperforates acted as trapping sites to localise the FexOy nanoparticles, thereby boosting the density of accessible active sites. Additionally, at the interfacial regions between the FexOy crystallites, a high density of oxygen vacancies with an oriented pattern was shown to create superlattice structures. The energy storage functionality of the defect-rich MCS/FexOy nanostructure with nanoperforated architecture was investigated, where the results exhibited a high gravimetric capacitance of 540 F g-1 at a current density of 1 A g-1 with outstanding capacitance retention of 73.6% after 14 000 cycles.

Recovery of heavy metals from waste printed circuit boards: statistical optimization of leaching and residue characterization.

Despite attempts to enhance the recycling of waste printed circuit boards (WPCBs), the simultaneous recovery of major metals of WPCBs using an efficient approach is still a great challenge. This study mainly concerned with applying an effective statistical tool to optimize the recovery of metal content (i.e., Cu, Fe, Zn, Pb, Ni, Sn, and Al) embedded in WPCBs using a leaching agent without any additive or oxidative agent. Another target was to optimize a multi-response recovery process by minimizing time, energy, and acid consumption during the leaching. Effective parameters and their levels, including leaching time (20-60 min), temperature (25-45 °C), solid to liquid (S/L) ratio (1/8-1/20 g/ml), and acid molarity (1-2.7 M), were optimized. A well-established statistical approach (i.e., response surface methodology (RSM)) was applied to precisely quantify and interpret the effects. General optimum conditions for nine responses were introduced with the desirability of ≈ 85%. Finally, the solid residue of leaching was characterized and results showed the morphology, structure, and composition of the residue content (i.e., polymers and ceramics) remained the same after the leaching, indicating the neutral behavior of the leaching process on these two materials. Also, thermal behavior and phase analysis of the original WPCBs and leaching residue were compared and analyzed. Graphical abstract.

Proton-assisted creation of controllable volumetric oxygen vacancies in ultrathin CeO2-x for pseudocapacitive energy storage applications.

Two-dimensional metal oxide pseudocapacitors are promising candidates for size-sensitive applications. However, they exhibit limited energy densities and inferior power densities. Here, we present an electrodeposition technique by which ultrathin CeO2-x films with controllable volumetric oxygen vacancy concentrations can be produced. This technique offers a layer-by-layer fabrication route for ultrathin CeO2-x films that render Ce3+ concentrations as high as ~60 at% and a volumetric capacitance of 1873 F cm-3, which is among the highest reported to the best of our knowledge. This exceptional behaviour originates from both volumetric oxygen vacancies, which enhance electron conduction, and intercrystallite water, which promotes proton conduction. Consequently, simultaneous charging on the surface and in the bulk occur, leading to the observation of redox pseudocapacitive behaviour in CeO2-x. Thermodynamic investigations reveal that the energy required for oxygen vacancy formation can be reduced significantly by proton-assisted reactions. This cyclic deposition technique represents an efficient method to fabricate metal oxides of precisely controlled defect concentrations and thicknesses.