Concrete face slabs (CFSs) are the core anti-seepage structures in concrete-faced rockfill dams, and their crack resistance is critical to dam safety. As such, special attention needs to be paid to preventing cracking in CFSs. High-altitude regions in China feature significant diurnal temperature variations, intense solar radiation, and dry air, which may cause internal-external temperature differences in CFSs, thus increasing the risk of thermal stress and cracking. This study investigates the temperature field and thermal stress in CFSs during construction. Realtime data on CFSs surface temperature and humidity, concrete pouring schedules, and environmental conditions were collected for analysis. Boundary conditions for simulating temperature field and thermal stress in CFSs are clearly defined. A thermal parameter inversion model is developed using a uniform design-neural network-genetic algorithm. Additionally, a discriminative model for tracking the pouring progress of CFSs is established based on fiber optic temperature monitoring data. In the finite element simulation, the CFS structure was divided into five zones based on the pouring sequence. Dynamic simulation of temperature field and thermal stress field was achieved. Results show that covering with 4-5 cm of foam board effectively meets early-age crack resistance requirements. In addition, applying river water curing at 10-14 degrees C significantly reduces tensile stress and helps meet anti-cracking criteria. The simulation method proposed in this study enables rapid and accurate assessment of the real construction conditions. Based on this analysis, effective temperature control strategies can be developed to prevent early-age cracking in CFSs, offering guidance for similar concrete projects in high-altitude regions.

When an open-circuit fault occurs in a dual three-phase permanent magnet synchronous motor (DTP-PMSM), the system is subject to both current and voltage constraints. Analysis of these voltage constraints reveals that voltage residuals that have been previously overlooked significantly contribute to torque ripple. This article proposes a dual-plane voltage compensation strategy. The harmonic-plane compensation is used to eliminate the dominant voltage residual, while the fundamental-plane compensation further eliminates the residual-induced voltage disturbance on the fundamental-plane control. The proposed method suppresses torque ripple under fault conditions and further reduces it during fault-tolerant operation. Experimental results validate their effectiveness.

A major unresolved challenge in inverted organic-inorganic hybrid perovskite solar cells (I-PSCs) is interfacial non-radiative recombination. To tackle this issue, we introduced trace dimethylformamide (tDMF) in isopropanol (tDMF/IPA) as a passivation material, carefully modifying the interface between FA0.95Cs0.05PbI3 and [6,6]-phenyl-C61-butyric acid methyl ester. The experimental results of energy dispersive X-ray spectroscopy at different voltages and angles, infrared spectroscopy, and X-ray photoelectron spectroscopy indicate that oxygen lone pair of electrons in carbonyl group (-C=O) of polar solvent N,N-dimethylformamide form coordination bonds (Pb2+ -> O=C) with Pb2+suspension bond on the surface of perovskite. Tafel polarization curve and dark current results reveal decrease in the charge recombination rate at the interface and decrease in leakage current, respectively, after tDMF/IPA passivation. The photoelectric conversion efficiency (PCE) of I-PSCs treated with tDMF/IPA is significantly increased from 21.44% to 23.24%, and the open-circuit voltage is also increased from 1.01 to 1.12 V. Encapsulated devices based on tDMF/IPA passivation retained over 77% of their initial PCE after being stored in ambient air for 2,736 h.

The detection and removal of heavy metal ions and organic dyes in wastewater are crucial yet highly challenging. Herein, we report a stable terbium-based metal-organic framework, LCUH-125, assembled from Tb3+ ions and an anthracene-containing aromatic carboxylic acid ligand. LCUH-125 features a two-dimensional layered structure further extended into a three-dimensional supramolecular network through anthracene π···π stacking, with an interlayer spacing of 6.0-6.34 Å. This structure provides abundant π···π and C-H···π interactions, enabling efficient adsorption of methylene blue (MB, 528.1 mg·g-1) and rhodamine B (RhB, 147.8 mg·g-1) and selective separation of MB/methyl orange and RhB/methyl orange mixtures. Benefiting from excellent luminescence and water stability, LCUH-125 serves as a highly selective and sensitive multiresponsive luminescent sensor for Fe3+, Cr3+, Al3+, and Cr2O72- in aqueous solution with high Stern-Volmer constants. The adsorption and sensing mechanisms were systematically elucidated by characterizations and theoretical calculations. This work offers a valuable strategy for designing dual-functional MOF materials for wastewater treatment and luminescent sensing.

This study explores the high-value utilization of industrial waste red mud (RM) by combining it with biomass-derived hydroxypropyl cellulose (HPC) to fabricate RM/HPC composites for use as electrocatalyst in dye-sensitized solar cells (DSCs). The composites were prepared via high-temperature treatment under a nitrogen atmosphere. Extensive characterization—including SEM, TEM, XRD, Raman, XPS, EPR, hysteresis loop, synchrotron radiation, and photoelectrochemical measurements—reveal that the optimal material, RM/HPC(1/1)-800 (1:1 mass ratio treated at 800 °C), possesses a hierarchical structure and magnetic properties. Notably, the Fe²⁺/Fe³⁺ ratio increased to 1.87. Electrochemical results demonstrate that the RM/HPC(1/1)-800 electrode exhibits exchange current density and charge-transfer resistance comparable to those of noble Pt electrode, along with excellent electrocatalytic activity and reversibility toward the I⁻/I₃⁻ redox couple. In the device testing, the DSCs of the electrodes using RM/HPC(1/1)-800 achieved a high power conversion efficiency, which was comparable to that of the DSCs based on Pt electrodes. This work demonstrates a promising strategy for transforming industrial waste into efficient, low-cost electrode materials for high-performance DSCs.

To address the challenges of labor-intensive operations, low automation, and delayed information interaction in bridge tower concrete construction, this paper proposes an integrated intelligent construction system incorporating automated concrete placement, vibration, temperature control, and curing functions. A closed-loop control method for the whole construction process based on digital twin technology is proposed. A four-layer “end–edge–cloud” architecture integrating the Internet of Things, multi-source sensing, and three-dimensional simulation enables real-time dynamic mapping and virtual–real interaction. Machine learning algorithms was employed to drive model updating and parameter optimization. A parameter optimization and feedback control mechanism was established. Laboratory experiments on a scaled system demonstrate millimeter-level virtual–real synchronization accuracy, with a mean trajectory tracking error of 0.76 mm and a temperature field prediction accuracy of 0.1℃. These findings verified the feasibility and effectiveness of the proposed digital twin architecture, providing a systematic technical solution for the intelligent upgrading of bridge tower concrete construction.

With the rapid growth of chemical data and information, there is an increasing need for analyzing large chemical datasets and extracting key or feature information. Currently, more than 100,000 types of metal-organic frameworks (MOFs), as the material recently awarded the Nobel Prize in Chemistry, have been experimentally synthesized. The performance of MOFs in adsorption-separation applications depends on their specific void characteristics, including void count, spatial distribution, and volume size. This study presents the entire process including data collection, recognition of key or feature information, the workflow of using Python tools, and the automatic output of results for void information, solvent accessible volume (SAV) and adsorbate molecules. By processing 219 CIF files collected from open-access publications, CCDC, and supporting information files, we successfully extracted 498 total blocks, including 259 blocks with void information, 157 blocks with SAV data, 286 blocks with squeeze details, and 1573 individual voids. In addition, we identified adsorbate molecules (diethyl ether, chloroform, water, ethanol, toluene, carbon dioxide) in MOFs. The method demonstrates computational efficiency, requiring only standard CPU resources to process large datasets.

With the escalating complexity of composite contamination in industrial wastewater, exploring high-efficiency and robust photocatalysts has become a research hotspot in environmental remediation. Herein, five isostructural rare-earth metal-organic frameworks (RE-MOFs, LCUH-128-132) were solvothermally assembled via the coordination of anthracene chromophore ligand 9,10-anthracenedicarboxylic acid (H2ADC) with five rare-earth metal ions (RE = Y, Eu, Gd, Tb, Dy). Remarkably, LCUH-129 (Eu-MOF) presents outstanding multifunctional photocatalytic activity without any additional photosensitizers or cocatalysts. It delivers a Cr(VI) reduction rate constant of 0.49 min-1, along with RhB and MB degradation rate constants of 0.23 min-1 and 0.026 min-1, respectively. The anthracene moiety serves as a light antenna to efficiently capture visible light; photogenerated electrons are rapidly transferred to rare-earth catalytic centers via ligand-to-metal charge transfer, which effectively inhibits electron-hole recombination. Radical trapping experiments and EPR characterization verify that ·OH, ·O2- radicals, and photogenerated electrons dominate the pollutant elimination processes. Furthermore, LCUH-129 exhibits excellent recyclability. This work affords a facile strategy for fabricating high-performance RE-MOF photocatalysts and reveals their promising prospects in the practical remediation of water composite pollution.

Red mud (RM) is an industrial waste with high alkalinity and high corrosiveness. Appropriately removing the alkalinity from RM is crucial for the reuse and application of RM. This study attempts to composite RM with polyvinyl chloride (PVC) for self-supplying NaCl electrolyte for supercapacitors. The carbon structure and chemical state of Fe in RM/PVC composites after carbonization at different temperatures were studied. The results show that, compared with RM, the content of Fe2+ in RM/PVC composites at 800 degrees C increased. The carbon in RM/PVC composites at 800 degrees C includes disordered and graphite carbon. Surprisingly, the specific capacitance of RM/PVC(1:1.67)-800 (1.59 F/g) under GCD test (5 mA/g) is two to three orders of magnitude higher than that of RM (1.7 mF/g) and PVC-800 (2.5 mF/g). It is worth noting that the electrolyte solution of this supercapacitor is NaCl derived from the reaction between the alkalinity in RM and HCl generated from PVC during the high-temperature carbonization process, which improves the safety and environmental friendliness of RM utilization. Therefore, in this work, the industrial waste RM was ingeniously combined with PVC to turn waste into treasure, thus paving the way for the development of using RM.

ObjectiveDuring dam construction, controlling the temperature of mass concrete is critical to preventing concrete cracking. As the size of concrete pours in modern dam construction increases and construction conditions become more complex, researchers have increasingly observed uneven temperature distribution within the pouring block. Traditional methods for monitoring concrete temperature primarily rely on spot thermometers, with key analysis indicators being the maximum temperature or the temperature difference between the interior and exterior. This analytical method cannot reflect the temperature distribution state within the pouring chamber. Although numerical simulation can simulate the temperature field of concrete. However, for temperature field simulation calculations of pouring chambers, the initial temperature distribution is typically assumed to be uniform. The temperature or average temperature from the commonly used spot thermometer is input into the simulation model. This calculation involves certain simplifying assumptions that limit the accuracy of the numerical simulation. To accurately reflect the temperature distribution within the pouring chamber, this study proposes utilizing actual field measurement data. Real temperature data is employed to reconstruct the temperature distribution within the pouring chamber. Therefore, this paper proposes a characterization method based on grid and domain analysis to reflect the phenomenon of uneven temperature distribution in real concrete.MethodsFirst, a staged definition of non-uniformity was formulated based on concrete age. For ages within 14 days, non-uniformity was defined by criteria related to concrete cracking risk, including whether the equivalent tensile stress from the maximum temperature difference exceeded the concrete tensile strength or if the temperature gradient surpassed a critical threshold. Beyond 14 days, non-uniformity was defined as the maximum temperature difference within the block exceeding a permissible variation amplitude, such as 2 °C. Second, a three-dimensional grid model of the pouring block was constructed, with each grid unit measuring 1 m × 1 m × 1 m. Grids containing concrete were defined as entity grids, while others representing the surrounding environment were termed empty grids. The neighborhood of a grid was defined as its face-adjacent grids. Third, two key indices were proposed. The Non-uniform Temperature Potential for a grid was defined as the difference between its temperature, interpolated from the nearest three optical fiber monitoring points using the Inverse Distance Weighting method, and the average temperature of the block. Perform vector synthesis of the uneven temperature potential at the central grid point with that of the adjacent grid points. The synthesized vector represents the intensity of temperature field inhomogeneity for this grid. Finally, this paper conducted a high-density temperature monitoring test at a certain arch dam construction site and verified the effectiveness of this method.Result and Discussion Apply the aforementioned characterization method for temperature field non-uniformity to the test chamber. Before the 14-day of the growth period, grids with a potential difference vector exceeding 3 °C/m accounted for 45% of the total grids. Results indicate that during the early pouring period, significant temperature distribution irregularities exist within the block thermal field. This proportion decreased to 14% after 28 days of age. Indicates that the temperature distribution within the pouring block has become more uniform over time. Analyze the spatial locations where uneven temperature distribution occurs. It has been observed that temperature distribution irregularities are more likely to occur at the boundary areas of the pouring block. The temperature field distribution contour map of the block layer was reconstructed. Within the 14-day aging period, the reconstructed temperature map shows a significant color difference between the central region and the boundary areas. The reconstruction results also indicate that the temperature distribution within the concrete silo is non-uniform. The reconstruction results are consistent with those obtained by the characterization method. The results from the cloud diagram validate the accuracy of the characterization findings proposed in this paper.ConclusionsThis paper proposes a method for characterizing temperature field non-uniformity in pouring block. Using indicators such as the grid method and potential difference vector, the distribution of the concrete temperature field is reflected. and demonstrated the feasibility of this approach at the engineering site. High-density temperature monitoring tests conducted at the engineering site have demonstrated the existence of non-uniformity temperature distribution within the pouring block. Spatially speaking, the temperature distribution is significantly more non-uniformity at the boundaries of the pouring block. Over time, the non-uniformity of the temperature field within the pouring block gradually diminishing. Meanwhile, the characterization method established in this paper provides a research foundation for subsequent studies on the evolution mechanism of temperature fields.

In the construction of conventional concrete high arch dams in high-altitude regions with large temperature variations, the prolonged and cold winters often force the suspension of concrete pouring, severely constraining the overall schedule. To address this limitation, this paper breaks away from the conventional winter-shutdown scheme by proposing a new technique: continuous construction under low-temperature conditions. It can adapt to large temperature variations, and this study develops a corresponding construction schedule simulation model for quantitative evaluation and scheme optimization. First, the influence of large diurnal temperature variations on high-altitude concrete pouring was analyzed. Based on this, a dynamic pouring technique for sub-blocks is proposed—thin-layer pouring during positive temperatures and insulation curing during negative temperatures—with the aim of transforming discrete climatic windows into a continuous construction period. Second, to accurately simulate this complex spatial partitioning and temporal scheduling process, a customized schedule simulation model based on discrete-event simulation (DES) theory was developed. The model incorporated meteorological recognition at low temperatures, dynamic dam-block partitioning, and sub-block pouring scheduling. Finally, a high arch dam on a plateau in Southwest China was used as an engineering case to compare two construction schemes: the low-temperature shutdown scheme and the continuous construction scheme. After validating the simulation model under parameter assumptions such as ideal resource availability and stable annual climate patterns, the results showed that the continuous construction scheme achieves a monthly average pouring volume of 33,721 m3 during the period with large diurnal temperature variations, which accounts for 42.48% of the average monthly pouring volume during the normal construction period. Compared to the low-temperature shutdown scheme, the coefficient of variation of the monthly pouring intensity decreases by about 40%, and the total construction period is shortened by approximately ten months. This demonstrates the potential for schedule optimization for continuous winter construction in simulation.

Red mud (RM), as an industrial waste, has long been threatening environmental resources due to its high alkalinity and corrosiveness. In this study, we report reusing of alkaline RM as self-supplied electrolytes (aRMS-electrolyte) and positive active material for aqueous supercapacitors. We designed three different structures of supercapacitors RM(+)/aRMS-electrolyte/AC(-), AC(+)/aRMS-electrolyte/RM(-), and RM(+)/aRMS-electrolyte/RM(-). The electrochemical results show that RM(+)/aRMS-electrolyte/AC(-) has a larger specific capacity (13.8 mF/g for RM(+)/aRMS-electrolyte/AC(-), 9.0 mF/g for AC(+)/aRMS-electrolyte/RM(-) and 9.8 mF/g for RM(+)/aRMS-electrolyte/RM(-) at 0.2 mA/g). The unique feature of this work lies in: (1) The electrolyte is entirely derived from the dissolution of the base in the RM. (2) Raw RM is directly applied to supercapacitors without any pretreatment, which is a very simple and straightforward solution. (3) The transformation from industrial waste to electrode materials has achieved high value of RM. (4) Using the alkaline sodium hydroxide naturally provided by red mud as an electrolyte in electrochemical devices may provide inspiration for electrochemical detection or electrochemical purification and refinement. In conclusion, this work has explored a possible path for the high value utilization of RM and the construction of new type electrochemical devices.

Capturing CO2 from natural gas and flue gas is of critical importance for energy conservation and achieving carbon-neutrality goals, yet it remains a significant challenge. Herein, we report two novel and stable 3D lanthanide MOFs, LCUH-123 and LCUH-124, which demonstrate remarkably selective CO2 adsorption over CH4 and N2, exhibiting excellent separation performance for both CO2/CH4 and CO2/N2 gas mixtures. LCUH-123's channel is obstructed by two coordinated DMF molecules, leading to near-complete blockage and a significantly reduced adsorption capacity. In contrast, LCUH-124's micropores are enriched with H2O-coordinated sites and free [(CH3)2NH2]+ cations, enabling superior gas adsorption and separation performance. Compared to LCUH-123, LCUH-124 exhibits significantly improved gas adsorption and separation performance, achieving higher selectivity coefficients for CO2/N2 and CO2/CH4 at zero coverage. Breakthrough experiments confirm that LCUH-124 serves as an efficient adsorbent for high-purity separation of CH4 and N2 from binary CO2/CH4 and CO2/N2 mixtures. Furthermore, its cost-effective synthetic process offers substantial economic advantages for large-scale applications. Theoretical calculations have elucidated the distinct adsorption and separation mechanisms of CO2/CH4 and CO2/N2 mixtures in LCUH-124. The exceptional performance of LCUH-124 stems from its rationally engineered pore architecture and cavity-directed coordination of water molecules with [NH2(CH3)2]+ cations within the channel.

The spatial-temporal conflicts in the construction process may cause a series of construction quality, safety and schedule problems. The outbreak of mechanical spatial-temporal conflict in the construction process of the arch dam pouring block is random and uncertain. Scientific simulation and preview of the pouring construction process and analysis of the level, time, and influence degree of the outbreak of spatial-temporal conflict are significant means to optimize the construction organization and management. According to the degree of spatial-temporal conflict and its effect on security and efficiency, the subsidiary space scope of construction machinery is divided into three levels from inside to outside. The quantification algorithm of spatial-temporal conflict is proposed based on the three-layered space and time-space microelement model. The discrete system theory is employed to develop a simulation framework that systematically incorporates four core components: simulation objectives, construction machinery operational cycles, resource allocation mechanisms, and modeling assumptions. Combined with the typical pouring block in Baihetan arch dam, the construction process is simulated and the visualization system is developed, which achieves the information integration such as the quantification of the spatial-temporal conflict, the analysis of the influence effects, and the visualization of conflict information. The system simulation results show that the spatial-temporal conflict problem always exists in the pouring construction process, the problems of security risk and efficiency loss are inevitable. And the reasonable unloading point planning and mechanical trajectory setting can effectively reduce the risk of spatial-temporal conflict. Those studies provide a reference for the rational organization and scientific decision-making of pouring construction activities, and new ideas and methods for the safe and efficient construction, as well as the scientific and refined management, of arch dams.

The cable crane is the core hoisting equipment for high arch dam construction, and its hoisting trajectory is critical for both operational efficiency and safety. However, current trajectory planning does not adequately consider the underactuated characteristics of the cable crane. For instance, sudden stops or abrupt changes in direction can easily induce large swings of the bucket, causing safety risks and equipment wear. To address this issue, this paper developed a trajectory planning model for obstacle avoidance with smooth transitions in cable crane hoisting for arch dams and solved the high-dimensional optimization problem using a path–velocity decoupling strategy. First, a shortest path with geometrical conciseness and free collision was generated based on an improved A* algorithm to reduce the frequency of directional changes. Next, for different hoisting scenarios, segmented S-curve and polynomial velocity functions were proposed to ensure smooth velocity transitions. Then, an orthogonal experimental design was employed to generate a cluster of candidate trajectories that meet kinematic constraints, from which the optimal trajectory was selected using a multi-objective evaluation function. The results demonstrate that the motion trajectory planned using the proposed method is notably smoother. Compared with the traditional trapezoidal velocity method, it reduces the maximum swing amplitude of the bucket by 40.78% at a modest time cost. In real-time obstacle avoidance scenarios, the approach outperforms emergency-stop strategies, reducing the bucket’s maximum swing amplitude by 30.48%. This work will provide a reference for engineers to optimize the trajectory of large lifting equipment in construction fields such as high arch dams and bridges.

An accurate method for concrete thermal parameter inversion is crucial for reliable dam thermal analysis results. However, blocks in dam structures, often comprise multiple material zones, each with distinct thermal properties. Utilizing inversion methods designed for single materials to solve such problems would reduce accuracy. Accordingly, this paper proposes a joint inversion method of multidimensional thermal parameters for concrete dams, leveraging the Sparrow Search Algorithm - Extreme Learning Machine (SSA-ELM) model. Firstly, a uniform design was employed to generate the input sample set of thermal parameters, which were sequentially substituted into the numerical model to obtain calculated temperatures. The calculated values were then compared with measured temperatures to establish the output sample set of thermal parameters and calculation errors. To tackle the increased dimensions of the inversions for multiple material zones, the ELM model was introduced, and the SSA was used to optimize the input layer weights and the bias parameters of the hidden layer in the ELM model, establishing a nonlinear mapping between thermal parameters and dam temperatures. Subsequently, based on the trained SSA-ELM model, an optimized function was established to minimize the temperature calculation errors, and the thermal parameters were solved through the SSA algorithm. Finally, the effectiveness and applicability of this method were validated through two engineering case studies, and its inversion performance was compared with that of the ELM and Back Propagation (BP) models. The results showed that the proposed SSA-ELM algorithm effectively achieved multidimensional thermal parameter inversion analysis with high precision for concrete dams.

Reasonable design of metal-organic frameworks (MOFs) with multifunction pore environment and anionic structure for proton conduction and dye adsorption has important application value. Herein, we report two novel and stable isomorphic three-dimensional (3D) lanthanide metal-organic frameworks (LCUH-121 and LCUH-122). Both MOFs have unique pore sizes, which are respectively made up of smaller proton-conducting channels (LCUH-121: 6.8 × 11.4 Å2, LCUH-122: 6.1 × 11.4 Å2) and larger dye adsorption cavities (LCUH-121: 10.2 × 11.4 Å2, LCUH-122: 10.1 × 11.4 Å2). Remarkably, the high-density dimethylamine cations ([(CH3)2NH2]+) in the one-dimensional channel also endow them with dual functions, exhibiting both efficient proton conduction pathways and excellent cationic dye adsorption performance. The abundance of dimethylamine cations and the special environment of small pores give LCUH-121 and LCUH-122 proton conductivity (σ) values as high as 1.62 × 10-2 and 1.46 × 10-2 S·cm-1 (80 °C, 100% RH), which is the highest reported anionic MOFs to date. Meanwhile, the synergistic effect of the optimal large pore size and anion framework resulted in adsorption capacities of 1.23 and 1.20 g·g-1 for methylene blue (MB) by LCUH-121 and LCUH-122, respectively, and exhibited record-breaking adsorption rate constants (0.0698 and 0.0662 g·mg-1·min-1). More importantly, the Grand Canonical Monte Carlo (GCMC) elucidated that the proton conduction mechanism and dye adsorption mechanism mainly rely on a unique size dual pathway mechanism, in which protons are conducted through the small-pore framework and dye molecules are accommodated in a large pore framework.

The accurate prediction of concrete temperature during arch dam construction is essential for crack prevention. The internal temperature of the poured blocks is influenced by dynamic factors such as material properties, age, heat dissipation conditions, and temperature control measures, which are highly time-varying. Conventional temperature prediction models, which rely on offline data training, struggle to capture these time-varying dynamics, resulting in insufficient prediction accuracy. To overcome these limitations, this study constructed a sparrow search algorithm–incremental support vector regression (SSA-ISVR) model for online concrete temperature prediction. First, the SSA was employed to optimize the penalty and kernel coefficients of the ISVR algorithm, minimizing errors between predicted and measured temperatures to establish a pretrained initial temperature prediction model. Second, untrained samples were dynamically monitored and incorporated using the Karush–Kuhn–Tucker (KKT) conditions to identify unlearned information, prompting model updates. Additionally, redundant samples were removed based on sample similarity and error-driven criteria to enhance training efficiency. Finally, the model’s accuracy and reliability were validated through actual case studies and compared to the LSTM, BP, and ISVR models. The results indicate that the SSA-ISVR model outperforms the aforementioned models, effectively capturing the temperature changes and accurately predicting the variations, with a mean absolute error of 0.14 °C.

Designing efficient photocatalysts for the reduction of hexavalent chromium (Cr(VI)) in wastewater was crucial but challenging. Herein, a nanoscale CdS@Ho-MOF photocatalyst composite was successfully synthesized by the anchoring of CdS quantum dots within the curved channels of Ho-MOF. The nanocomposite CdS@Ho-MOF-43.66% demonstrated outstanding performance, efficiently and swiftly photocatalyzing Cr(VI) to Cr(III) in aqueous solutions, which solely utilized water as the electron donor, eliminating the need for additional photosensitizers or cocatalysts. Under visible light irradiation and acidic conditions, CdS@Ho-MOF-43.66% showed a high rate constant (k) of 1.39 min-1, a fast reduction rate of 12.41 mg Cr(VI) g-1 cata min-1, and a superior reaction efficiency of 99%. The composite material demonstrated a 5-fold and 11-fold enhancement in reaction rate compared to pure CdS quantum dots and Ho-MOF, respectively, highlighting its synergistic catalytic superiority. Impressively, the prominent performance remained remarkably consistent even after undergoing seven cycles. The formation of an indirect Z-scheme heterojunction between CdS and Ho-MOF within the nanocomposite predominantly accounted for the elevated photocatalytic performance, which enhanced the separation efficiency of photogenerated charge carriers. This study provided an avenue for the development of cost-effective and high-performance photothermal catalysts for the catalytic reduction of Cr(VI).

The reuse of industrial ore fertilizers (IOF) is of great significance for environmental pollution and for broadening the application field of IOF, which has the advantages of abundant raw materials and low price. In this study, we used IOF mainly containing Al, O, C, Na, V, F elements to prepare the cathode electrocatalyst by calcination (100, 400, 600 and 800℃ in N2) and post-washing method as counter electrode for dye-sensitized solar cells (DSCs). The electrochemical test showed that the photovoltaic parameters (VOC = 0.75 V, JSC= 14.74 mA/cm-2, FF= 0.53 and PCE=6.0 %) of DSCs based on IOF calcinating at 600 ℃ (IOF-600) were close to those (VOC=0.83 V, JSC = 13.30 mA/cm-2, FF = 0. 57 and PCE=6.36 %) of DSCs based on noble metal Pt. The result of SEM indicate that IOF-600 has a porous structure and is conducive to increase active sites, contact area with reactive species, and the diffusion of electrolyte solution. The electrochemical mechanism studies showed that V-IOF-600 showed good catalytic activity for iodine reduction reaction due to small charge transport resistance. IOF had the advantages of abundant materials and low cost, its reusing as cathode catalyst for DSCs is in line with the concept of green and sustainable development. This study provides ideas and methods for the reusing of other industrial fertilizers.