The market demand for environmentally controlled agricultural indoor lighting is gradually increasing due to environmental pollution and drastic changes in the natural climate. Generally, matrix K3YSi2O7 (phase 1) is difficult to synthesize compared to K3YSi2O7 (phase 2), which has been illustrated by theoretical calculations. In this paper, large quantities of pure phase K3YSi2O7 (phase 1) matrix were obtained by the substitution engineering strategy (Ca2+→Y3+). Subsequently, Eu2+ was doped to obtain a thermally stable ultra-wideband deep red light-emitting phosphor with an emission band centered at 721 nm and a full width at half maximum of 186 nm under 450 nm light excitation. It is noteworthy that compared with K3YSi2O7:Eu (phase 2), K3Ca0.3Y0.7Si2O7:Eu2+ (phase 1) is superior in terms of emission wavelength, full width at half maximum, and thermal stability. Furthermore, the spectrum resemblance between its emission spectrum and the photosensitive pigment Pfr was calculated to be 97.5%, which set the stage for subsequent plant lighting applications. Finally, light-emitting diode devices were prepared using K3Ca0.3Y0.7Si2O7:Eu2+ phosphor for plant lighting experiments, and plants grown under deep red light emitting diode light show more luxuriant growth. The results show that the phosphor K3Ca0.3Y0.7Si2O7:Eu2+ has promising applications in indoor plant culture. Meanwhile, the successful implementation of ion substitution engineering also provides a new strategy for transitions in host systems.

Molybdenum carbide (MoC) is a promising candidate for substituting expensive platinum-group metals in many applications owing to its low cost and excellent properties. A comprehensive understanding of the carrier dynamics in MoC facilitates its implementations and helps designing synthesis strategies. In this work, the carrier relaxation in MoC nanosheets is investigated by combining femtosecond transient reflection spectroscopy with first-principles calculations. The observed processes of electron-electron, electron-phonon, and phonon-phonon scattering show longer lifetimes compared to those of other transition metal carbides. The nanosecond carrier lifetime is explained by the restricted phonon decay pathways induced by the large mass difference between C and Mo atoms, which is revealed through the analysis of calculated phonon dispersion. The slow cooling of hot carriers in MoC nanosheets offers a simple approach for designing devices that effectively utilize hot carriers, which are expected to improve photothermal and photovoltaic performances.

Hexavalent chromium (Cr(VI)) contamination in groundwater poses serious threats to human health and the environment. This study synthesized sodium alginate-encapsulated nano-zero-valent iron supported on graphene oxide gel beads (SA/NZVI-rGO) for Cr(VI) removal and systematically investigated the effect of humic acid (HA) on its removal performance, revealing in depth the pH-dependent mechanism by which HA enhances Cr(VI) removal. Under acidic conditions, HA significantly increased the Cr(VI) removal rate by enhancing electrostatic adsorption. Under neutral and alkaline conditions, although electrostatic repulsion existed, HA still accelerated the reaction rate and improved the final removal efficiency. This is because the quinone/hydroquinone groups in HA act as electron shuttles, facilitating electron transfer from NZVI to Cr(VI). In addition, the resulting Cr(III) can form stable complexes with HA, which synergistically promote Cr(VI) removal. Kinetic analysis indicated that the process followed the pseudo-second-order model (R2 = 0.999), and the adsorption isotherm conformed to the Freundlich model (R2 = 0.974). Response surface methodology (RSM) was applied to optimize four parameters: pH, Cr(VI) concentration, HA concentration, and reaction time. The RSM model was highly reliable (P < 0.0001, R2 = 0.9936), predicting optimal removal conditions were: pH 3.14, initial Cr(VI) concentration 15.14 mg/L, HA concentration 12.79 mg/L, reaction time 33 min, and SA/NZVI-rGO achieved 100

Understanding rate-induced degradation mechanisms is essential for ensuring the reliable operation of lithium-ion batteries under fast-discharging conditions. This study systematically examines LiFePO4/graphite cells cycled across a broad spectrum of discharge rates (1C-10C) to elucidate rate-dependent aging behaviors and failure mechanisms. A multiscale characterization framework-spanning from the electrode to the nanoscale and integrating electrochemical, thermal, morphological, and interfacial analyses-was developed to uncover the progressive degradation processes. Electrochemical analyses indicate that capacity fade is governed primarily by lithium inventory loss (LLI) rather than active material degradation (LAM), with lithium plating occurring above 3C and dendritic growth dominating at 5C. Morphological observations demonstrate that while the cathode structure remains largely intact, high-rate cycling induces particle cracking, interfacial instability, and CEI thickening. In contrast, the anode exhibited pronounced surface degradation, SEI growth, and increased severity of lithium plating, as confirmed by surface-sensitive chemical analyses and fluorescence imaging. Finite element simulations further revealed increasing spatial inhomogeneity in the potential distribution and electrode utilization with increasing discharge rates, aligning with the observed electrochemical and structural gradients. The study provides a quantitative and mechanistic understanding of how high-rate operation accelerates anode failure and interfacial degradation, offering critical insights for lifetime modeling and the optimization of fast-discharging protocols in commercial lithium-ion batteries. (c) 2025 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

A membrane electrode assembly (MEA) based electrolyser is designed and fabricated for H-acid wastewater treatment and harmful chemical degradation. The electrochemical O3 and H2O2 generation performance has been greatly enhanced owing to the nano PbO2 catalyst on the anode and the PTFE/C catalyst on the cathode. Since the anode oxidation (AO) combined with oxygen reduction reaction (ORR) enhances ·OH radical generation, the in situ AO-ORR coupling system shows better mineralization efficiency and lower electrochemical energy consumption for organic degradation. Additionally, the nano PbO2 anode exhibited excellent stability and maintained high degradation efficiencies after 15 times of successive reuse of the in situ AO-ORR coupling system. Based on 16 identified intermediates categorized as primary, secondary, and downstream intermediates, a possible degradation pathway of the H-acid electrochemical oxidation was proposed and the toxicity was drastically reduced after the degradation.

The challenges of instability and surface defects in CsPbBrxI3-x nanocrystals (NCs) pose significant limitations on their potential application in high-performance pure-red perovskite light-emitting diodes (PeLEDs). Herein, a synergistic strategy of divalent cation (Zn2+) doping and anion (Te2-) passivation is proposed to solve these issues. Density functional theory analysis reveals that the synergistic effect can not only reduce the formation energy of CsPbBrxI3-x NCs but also increase theiodide vacancy defect formation energy of CsPbBrxI3-x NCs. Consequently, the optimized Zn2+/Te2- co-modified CsPbBrxI3-x NCs exhibit significantly enhanced stability with a near-unity photoluminescence efficiency. Pure-red PeLEDs based on these CsPbBrxI3-x NCs possess outstanding spectral stability with a maximum external quantum efficiency and luminance of 16.1% and 1397.2 cd m(-2), respectively. This synergistic strategy provides a new approach for enhancing the performance of mixed halide perovskite NCs and the corresponding optoelectronic devices.

Iridium oxide is recognized as the best oxygen evolution anode material due to its excellent electrocatalytic activity and long-term stability in acidic environment. Electrodeposition, as a new method for preparing iridium oxide catalysts, has attracted extensive attention in recent years. We report a triangular-wave electrodeposition method for the preparation of iridium oxide electrodes and successfully synthesized highly active IrO x electrodes with ultralow iridium loading. The IrO x electrode prepared at 100 mV s −1 for 100 cycles exhibited a superior mass activity of 3.11 A mg Ir −1 , while the IrO x electrodeposited at 20 mV s −1 for 500 cycles has the best apparent electrocatalytic activity, Tafel slope as low as 54.75 mV dec −1 . Physical characterization and electrochemical experiments show that the calcination treatment plays an important role in enhancing the OER performance of the electrodes. Remarkably, the calcined IrO x -TWE/Ti can continuously catalyze OER in 0.5 M H 2 SO 4 at 50 mA cm −2 for 150 h with a slight performance decay, demonstrating a supper large stability number of 2.78 × 10 5 . This work provides some valuable insights into the application of electrodeposition-based iridium oxide to practical industrial systems.

The Development of highly catalytically active and stable anodes for oxygen evolution reaction (OER) in acidic media remains a great challenge. Herein, we proposed a two-step electrodeposition method to optimize an amorphous electrodeposited IrOx electrode (eII-IrOx/Ti). The introduction of a pre-deposition layer, prepared by triangular wave electrodeposition, contributes to the enhancement of surface oxygen vacancies, resulting in a semi-crystalline structure. Compared to directly potentiostatic electrodeposited IrOx electrode (e-IrOx/Ti) and industrially thermally decomposed IrO2 electrode (IrO2-Ta2O5/Ti) at the same iridium loading level, eII-IrOx/Ti exhibited superior OER performance, with a Tafel slope of 52.85 mV/dec and an overpotential as low as 218 mV at 10 mA/cm2. Moreover, eII-IrOx/Ti demonstrates remarkable stability while continuously catalyzing OER at 250 mA/cm2 for 100 h, with little performance decay and a stability number of 3.397 x 106 (comparable to crystal IrO2). The semi-crystalline structure of eII-IrOx/Ti, rich in oxygen vacancies, facilitates the synergistic effect of amorphous and crystalline phases, indicating the potential of electrodeposited IrOx electrodes for sustained and efficient OER in acidic environments.(c) 2023 Elsevier Ltd. All rights reserved.

Shape-controlled nanomaterials of PbO2 have attracted considerable attention in designing highly efficient electrocatalyst, since the physicochemical properties of PbO2 vary from their structure and morphology. PbO2 materials demonstrating promising ability in electrochemical ozone production (EOP) have attracted the focus of research recently, and therefore boost the strategical improvement in their key performance, such as electroactivity, current efficiency and space-time yield. In this work, the PbO2 crystals with controllable structures of rod-like, sphere-like as well as star-like PbO2 were acquired to explore their physicochemical properties and EOP performance systemically. Among the samples, PbO2 nanorods, benefitting from their abundant active surface chemisorbed oxygen, exhibit relatively high electrocatalytic activity towards EOP. Such structural feature is beneficial for triggering the generation of a rapid charge, improving mass transfer, and subsequently enhancing the corresponding electrocatalytic reactions. A maximum EOP current efficiency of 14% was achieved by the PbO2 nanorod electrode at a cell potential of 4.0 V corresponding to a specific electric energy consumption of 101.53 kWh center dot(kg center dot O-3)(-1). Overall, an in-depth understanding of the nanostructure-performance relationship of PbO2 and EOP performance is demonstrated in this work, which can provide an insight into the rational design of PbO2 for the EOP.

Dimensional stable anodes (DSA) have shown exceptional performance in water electrolysis, but their high cost and scarcity raise concerns. Seeking more efficient utilization of Ir-based catalysts is crucial. This study investigates the catalytic performance and stability of Ti-based electrodeposited iridium oxide electrodes (e-IrOx/Ti) for the oxygen evolution reaction (OER) in acidic media, focusing on the impact of different temperature thermal treatments on their crystal structure, electronic structure, Raman spectroscopy, and cyclic voltammetry. The thermal treatment temperature influences the deposition layer, gradually transforming amorphous IrOx into rutile-type IrO2 with enhanced crystallinity. At 450°C, the deposition layer exhibits a mixed phase of Ir2O3 and IrO2, with Raman features suggesting an [IrO6]n edge-sharing polyhedra (with n ≥ 3) structure, leading to improved OER electrocatalytic performance. However, higher temperatures (≥550°C) result in the formation of K0.25IrO2 and decreased electrochemically active surface area. Accelerated lifetime testing reveals impressive stability and substantial service life for e-IrOx/Ti-450 electrodes. The dissolution of iridium in the OER reaction indicates a coupling of lattice oxygen and adsorbate evolution mechanisms for the electrocatalysis of e-IrOx/Ti. These findings offer valuable insights for designing efficient and stable OER catalysts.

An ozone generator with long-term stable operation, high ozone output, and low production energy was investigated based on a high-performance PbO 2 gas diffusion electrode.

To develop efficient, viable, and promising routes to regenerate nano-LiFePO4 (nano-LFP) composite materials from spent LFP batteries, this paper studied phosphate approaches by taking Li3PO4 and FePO4 as raw materials. The crystalline structure, morphology, and physicochemical properties of regenerated LiFePO4 nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and electrochemical measurement. Regenerated LiFePO4 owned a good olivine structure with a space group of Pnma. After being coated with carbon, rectangular-structured LiFePO4 prepared by hydrothermal synthesis exhibited high specific capacity, excellent rate capability, and good Li+ diffusivity. When the pH value was around 8.0 and the amount of the Li3PO4 raw material was 14 mmol, the discharge capacity at 0.1C was 158.6 mAh g-1 and the capacity retention rate was 99.19% at 1C after 300 cycles. Meanwhile, flake-like LiFePO4/C synthesized by the carbothermal method at 700 degrees C and a 14 wt % carbon mass fraction showed an initial discharge capacity of 159.0 mAh g-1 at 0.1C and a capacity retention rate of 97.45% after 300 cycles at 1C, exhibiting excellent electrochemical performance. Overall, this study provides a facile, feasible, and sustainable recovery method for the battery industry for recovering phosphate products from spent LFP cathode materials and subsequent large-scale regeneration of LiFePO4 composite materials.

On-site H2O2 synthesis via the two-electron route oxygen reduction reaction for environmental remediation is attractive. This work offers a novel strategy for both spent graphite recovery and H2O2 electrosynthesis catalyst preparation. The graphite is directly recycled from spent lithium-ion batteries to an H2O2 electrosynthesis catalyst. From the view of sustainable development and environmental protection, the H2O2 electrosynthesis catalyst prepared using spent graphite is eco-friendly and cost-efficient. The surface functional groups of the recycled graphite are finely tuned by the HNO3 medium to induce -COOH and C-O-C groups. The activated graphite exhibits high H2O2 activity and selectivity, compared to the raw spent graphite. The activated graphite can achieve an H2O2 Faradic efficiency of about 80%. The activated graphite has a good prospect for T-acid wastewater treatment as the H2O2 generation catalyst. Almost 92% of chemical oxygen demand can be removed.

Ensuring or even optimizing the activity and stability of iridium oxide-coated titanium anodes while reducing the amount of iridium is still practically significant. In this work, IrOx-Ti electrodes are prepared by galvanostatic deposition at different deposition current densities and times. The iridium loading level, morphology, microstructure, and element composition distribution of these obtained electrodes are characterized, and their cyclic voltammetry and accelerated life tests were carried out in 0.5 M H2SO4 to investigate their electrochemical performance for the acidic oxygen evolution reaction (OER). For a better understanding of the anodic electrodeposition mechanism, a competing mechanistic hypothesis was proposed to describe the reactions and their relationship involved in this process. The results show that the IrOx electrodes electrodeposited at 0.1 mA cm(-2) exhibited a superior performance for the OER in terms of stability. Especially, the electrode electrodeposited for 5 h (0.1 mA cm(-2)) demonstrated a long-term durability for 73.14 h (equivalent to at least 14,642 h, i.e., 610 days, in actual lifetime) with 1.0 mg cm(-2) iridium loading. Simultaneously, a mathematical model was used to fit the relationship between accelerated lifetime and deposition current and iridium loading. This research provides some valuable insights into how to optimally use Ir as an OER electrocatalyst.

Spent lithium iron phosphate (LFP) battery recycling has to avoid excessive reagent cost and secondary pollution, such as waste acid. This research proposed a solid-state electrolysis method to reduce reagent cost and wastewater amount. This method was similar to the discharge mechanism of the lithium-ion battery, which innovatively adopted solid-state electrode reactions to leach Li and Fe into the phosphoric acid electrolyte. Meanwhile, several key performance indicators of such electrolyzers were evaluated. The time-space yield of the solid-state electrodes reached 108.17 g m(-2) h(-1). The leaching efficiency of Li and Fe reached 98.23 and 96.06%, respectively, with electric energy consumption of only 578.15 kW h per ton spent LFP cathode materials. The apparent leaching kinetics analysis determined the control step of the Li and Fe leaching process. The recovery rates of Li and Fe were 93.51 and 97.96%, respectively. Battery-grade FePO4 and Li3PO4 products were derived, which were directly employed for LiFePO4 reproduction. With further evaporation to prepare NH4H2PO4, there was no waste water in all processes of this novel recycling method. This study demonstrates the possibility of green and efficient spent LFP recovery and contributes to environmental protection and sustainable development of resources.

Chemical oxygen demand (COD) is a critical analytical parameter for organic pollutants in the aqueous system. Most COD detection methods have disadvantages such as virulence, time-consuming and complicated steps, which makes the exploration of suitable COD detection methods an important challenge. In this work, a novel nano-PbO2-composite electrochemical sensor was fabricated, and its electrochemical sensing properties for COD detection were investigated. The surface morphology and construction of nano-PbO2-composite electrodes were investigated using scanning electron microscope (SEM) and X-ray diffraction (XRD), which showed that the substrates were completely covered by nano-PbO2. The linear sweep voltammetry (LSV), the hydroxyl radical (center dot OH) generation ability, and electrochemical impedance spectroscopy (EIS) were employed to study the electrochemical properties. Good analytical characteristics in standard glucose solutions were achieved with Tib/ SnO2-Sb2O3/beta-PbO2 sensor. In particular, Tib/SnO2-Sb2O3/beta-PbO2 showed a good correlation between the sensor response and the COD values, which exhibited a linear range from about 500-9000 mg.L-1. Generally, the nanoPbO2 sensor displayed fast-response speed and simple instrumentation, which is promising for the COD determination with low cost, high detection sensitivity, and wide linear range.

Lead dioxide (PbO2) materials have been widely employed in various fields such as batteries, electrochemical engineering, and more recently environmental engineering as anode materials, due to their unique physicochemical properties. Key performances of PbO2 electrodes, such as energy efficiency and space-time yield, are influenced by morphological as well as compositional factors. Micro-nano structure regulation and decoration of metal/non-metal on PbO2 is an outstanding technique to revamp its electrocatalytic activities and enhance environmental engineering efficiency. The aim of this review is to comprehensively summarize the recent research progress in the morphology control, the structure constructions, and the element doping of PbO2 materials, further with many environmental application cases evaluated. Concerning electrochemical environmental engineering, the lead dioxide employed in chemical oxygen demand detection, ozone generators, and wastewater treatment has been comprehensively reviewed. In addition, the future research perspectives, challenges and the opportunities on PbO2 materials for environmental applications are proposed.

The anodic electrodeposition process of iridium oxide on Ti, Pt, Au, and glassy carbon was investigated from cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The electrocrystallization process of iridium oxide electrodeposition based on different substrates behaved consistent with the diffusion-controlled three-dimensional nucleation process, and a nucleation mode capable of expressing the process was established. Depending on the nucleation model parameters, the iridium oxide electrodeposition on Ti with the highest nucleation rate and active nucleation sites showed excellent nucleation performance, while the k O E R value of the electrodeposition on Au is the largest, indicating that Au-base electrodeposited iridium oxide can support more favorable kinetics for OER. Furthermore, the morphology and chemical composition of the electrodeposited IrO x electrodes based on different substrates were characterized by scanning electron microscope (SEM) and X-ray photoelectron microscopy (XPS), and then measured through a series of electrochemical characterization experiments. Although the SEM image of IrO x layer electrodeposited on Ti is relatively uniform and have higher IrO 2 content compared to other substrates, its electrocatalytic activity is poor, while the IrOx-Au electrode exhibits the best OER performance with a current density of 10 mA cm −2 and an overpotential of 0.2 V.

To develop an efficient and green method to recycling lead slag, a novel strategy to fabricate nano-lead dioxide from lead slag was applied by the hydro-electrometallurgy. In leaching system, the optimum condition of leaching time 100 min, 80 °C, stirring rate 500 rpm, liquid/solid ratio 20 and 1 mol/L methanesulfonic acid resulted in lead recovery of 89% and residue obtained without toxicity. The kinetic study revealed that the methanesulfonic acid leaching of lead slag shows good agreement with a diffusion-controlled shrinking-particle model. Additionally, the apparent activation energy of MSA leaching of lead slag was determined using Arrhenius model as 13.621 kJ/mol. Furthermore, Nano-PbO2 recovered from waste lead paste was prepared for the electrolysis of water to produce ozone. The experimental results showed that the ozone production of nano-PbO2 recovered from waste lead slag was not significantly different from the nano-PbO2 prepared by pure reagents. In conclusion, waste lead slag can be recycled for the fabrication of nano-PbO2, which has a significant advantage on realizing the recycling of lead resources.

The electrodes were fabricated in double-titanium cyclic voltametric electrodeposition system, corresponding to the anode and cathode of the system. For further study the practicality of this mode, the performance of the resulting electrodes was investigated. Through a series of physical and electrochemical characterization, it is concluded that the IrOx electrode corresponding to the anode of the system has a flat and uniform deposit layer, and shows better electrolytic durability (its actual working life is more than 3072 h), while the cathode electrode has better performance in electrocatalytic activity.