Visible-Near Infrared Independent Modulation of Hexagonal WO3 Induced by Ionic Insertion Sequence and Cavity Characteristics.

Dual-band electrochromic materials have attracted significant attention due to their ability to independently control sunlight and solar heat. However, these materials generally exhibit notable limitations, and the mechanisms for their dual-band independent regulation remain poorly understood. Here, the visible-NIR-independent regulation capabilities of hexagonal WO3 (h-WO3) are introduced for the first time. A structure-activity relationship that perfectly links the microscopic ion insertion sequence and cavity characteristics to the macroscopic dual-band electrochromic properties is established. The progressive ion intercalation process and the distinctive optical activity of the cavities are keys for enabling h-WO3 to independently modulate "bright," "cool," and "dark" modes. Notably, h-WO3 demonstrates superior dual-band electrochromic performance with a broadband full shielding effect from 550 to 2000 nm, achieving the widest full shielding band in dual-band electrochromic studies. Additionally, h-WO3 shows a high discharge capacity of 270.9 mAh m- 2 at 0.25 A m- 2, and requires only 49.1 and 209.7 mAh m- 2 to complete a full round-trip switch between "bright-cool" and "bright-dark" modes, respectively. The constructed device offers a dynamic temperature control range of up to 10.5 °C and supports a maximum voltage of 2.86 V, underscoring its considerable potential for practical applications and energy efficiency.

Transformation and Detoxification of Typical Metallurgical Hazardous Waste into a Resource: A Review of the Development of Harmless Treatment and Utilization in China.

The production process of the metallurgical industry generates a significant quantity of hazardous waste. At present, the common disposal method for metallurgical hazardous waste is landfilling, which synchronously leads to the leaching of toxic elements and the loss of valuable metals. This paper presents a comprehensive review of the research progress in the harmless treatment and resource utilization of stainless steel dust/sludge (including stainless steel dust and stainless steel pickling sludge) and aluminum ash (including primary aluminum ash and secondary aluminum dross), which serve as representative hazardous wastes in ferrous metallurgy and nonferrous metallurgy, respectively. Additionally, the general steps involved in the comprehensive utilization of metallurgical hazardous waste are summarized. Finally, this paper provides a prospective analysis on the future development and research trends of comprehensive utilization for metallurgical hazardous waste, aiming to offer a basis for the future harmless, high-value, resource-based treatment of metallurgical hazardous waste and the realization of industrial applications in China.

A novel green deep eutectic solvent for one-step selective separation of valuable metals from spent lithium batteries: Bifunctional effect and mechanism.

This study used a novel green bifunctional deep eutectic solvent (DES) containing ethylene glycol (EG) and tartaric acid (TA) for the efficient and selective recovery of cathode active materials (LiCoO2 and Li3.2Ni2.4Co1.0Mn1.4O8.3) used in lithium-ion batteries through one-step in-situ separation of Li and Co/Ni/Mn. The effects of leaching parameters on the recovery of Li and Co (ηLi and ηCo) from LiCoO2 are discussed, and the optimal reaction conditions are verified, for the first time, using a response surface method. The results demonstrate that under optimal conditions (120 °C, 12 h, EG to TA mole ratio (MEG:TA) of 5:1, and solid to liquid ratio (RS/L) of 20 g/L), the ηLi from LiCoO2 reached 98.34%, and Co was formed as a purple precipitate of cobalt tartrate (CoC4H4O6), which was transformed into a black powder of Co3O4 after calcination. Notably, the ηLi for DES 5 EG:1 TA was maintained at 80% after five cycles, indicating good cyclic stability. When the as-prepared DES was used to leach the spent active material Li3.2Ni2.4Co1.0Mn1.4O8.3, the in-situ selective separation of Li (ηLi = 98.86%) from other valuable elements such as Ni, Mn, and Co, was achieved, indicating the good selective leaching capacity and practical application potential of the DES.

A clean approach for detoxification of industrial chromium-bearing stainless steel slag: Selective crystallization control and binary basicity effect.

The complete detoxification and resource utilization of stainless steel slag are still facing challenges. In this paper, the harmless treatment of industrial stainless steel slag was realized by using a high temperature modification-crystallization control approach, and the influence of binary basicity (B) on selective enrichment of Cr-containing spinel in the slag and corresponding detoxification effect were systematically explored. Results demonstrated that the enrichment degree of Cr and the amount of Cr-bearing spinel separately reached 98.62 wt% and 13.32 wt% when B= 1.2. The reason was that low alkalinity promoted the reaction of Cr in slag to form Cr-containing spinel, thus improving the enrichment of Cr in the spinel and reducing the occurrence probability of Cr in the matrix phase. Furthermore, the toxicity test of modified slag powder was proceeded according to Chinese standard HJ/T 299-2007 and American standard EPA (Toxicity Characteristic Leaching Procedure, TCLP), and the feasibility of using modified slags as admixture for producing cement was discussed. Even if TCLP was adopted, the Cr leaching concentration in modified slag powder with B= 1.2 was only 1.59 mg/L, which was far lower than the national limit of heavy metal leaching concentration (15 mg/L) of solid waste. Remarkably, when the powder was formed as cement, the Cr leaching concentration was even lower than ICP-OES detection line. Meanwhile, its mechanical property was better than that of cement prepared without powder, indicating the detoxified slag powder met the requirements of concrete admixture. This paper provides a new way with certain economic value for detoxification and large-scale utilization of stainless steel slag.

Facile and large-scale fabrication of (Mg,Ni)(Fe,Al)2O4 heterogeneous photo-Fenton-like catalyst from saprolite laterite ore for effective removal of organic contaminants.

A facile and cost effective acid leaching-coprecipitation method was developed to prepare spinel-type (Mg,Ni)(Fe,Al)2O4 from saprolite laterite ore in large scale. The as-prepared (Mg,Ni)(Fe,Al)2O4 exhibited excellent photo-Fenton-like catalytic activity in decomposing different kinds of organic dyes and antibiotic tetracycline in the present of oxalic acid (H2C2O4). The influential factors of RhB degradation efficiency were investigated, including the (Mg,Ni)(Fe,Al)2O4 dosage, H2C2O4 concentration and the intensity of simulated sunlight. Meanwhile, the reaction mechanism of (Mg,Ni)(Fe,Al)2O4/H2C2O4/simulated sunlight system was also proposed. As the formation of highly photochemical [≡Fe(C2O4)3]3- complex ions on the surface of the (Mg,Ni)(Fe,Al)2O4, the obtained (Mg,Ni)(Fe,Al)2O4 showed degradation efficiency (η) over 90.0 % for common organic dyes and antibiotic tetracycline within 180 min under the optimum conditions. The η and TOC removal for RhB were still over 98.0 % and 46.0 % after five reuse cycles, respectively. The excellent catalytic performance and recyclability make the (Mg,Ni)(Fe,Al)2O4 fabricated from natural saprolite laterite ore more competitive in dealing with wastewaters contaminated by organic pollutants.

Efficient Nanorod Array Perovskite Solar Cells: A Suitable Structure for High Strontium Substitution in Nature.

Organic-inorganic hybrid perovskite solar cells (PSCs) have become a research hotspot because of their excellent power conversion efficiency (PCE), but the presence of toxic lead (Pb) in perovskite films has significantly limited their commercial applications. In this study, using a TiO2 nanorod array (TNRA) as the electron transport layer, strontium chloride (SrCl2) was chosen to fabricate lead-less PSCs in air (relative humidity, RH = 50%) by a simple two-step spin-coating method. The influence of introduced strontium (Sr) on the perovskite films and cell properties was systematically investigated by various characterization methods. With an increasing Sr substitution amount from 0 to 15 mol %, the formed perovskite films with a compact structure and large crystalline size essentially remained invariable, while the amount of residual PbI2 was reduced, which is beneficial for the cell performance. An optimal PCE of 16.08% (average PCE = 15.37%) was obtained for the 5 mol % Sr-substituted PSCs because of the enhanced charge extraction from the perovskite films to the TNRAs and the suppressed charge recombination in the PSCs. Both the humidity and thermal stability of the Sr-substituted PSCs were improved. More importantly, the 15 mol % Sr-substituted PSCs still exhibited a PCE of 15.09% in air (RH = 50%), maintaining 99% of the cell efficiency of the pristine (0 mol % Sr) PSC (15.27%), suggesting that the structure of TNRAs is suitable for the synthesis of high-performance Sr-substituted lead-less PSCs.