To improve the dispersion and electronic transmission performance of carbon nitride (C3N4), an electrostatic field regulation strategy was developed for constructing an ultra-dispersed and high reactive W-doped C3N4/ceramic (W/C3N4@ceramic) composite, which was used as a photocatalyst for degrading low-concentration cetyltrimethylammonium bromide (CTAB) under visible light irradiation to achieve the goal of “enhanced enrichment/catalytic degradation”. The ceramic with strong electrostatic field can rapidly capture the interlayer electrons and break the hydrogen bonds in the lamellar skeletons of massive C3N4, leading to the structure of C3N4 from bulk to nanosheet. W/C3N4@ceramic exhibited outstanding adsorption capacity (CTAB removal rate of 68.2% within 30 min in the dark) and photocatalytic activity (CTAB degradation rate of 93.9% within 90 min under light irradiation), which were much higher than those adsorbed (21.9%) and photocatalyzed (46.6%) by W/C3N4. The improved photocatalytic activity can be ascribed to that the ultra-dispersed nanosheets shortened the charge transfer path to accelerate the transmission and separation efficiency of photogenerated charges and increase specific surface area to provide abundant active sites. Moreover, CTAB can be spontaneously adsorbed on the surface of ceramic driven by electrostatic field, thus accelerating the interfacial transport and promoting photocatalytic efficiency. This work provides a novel strategy for the development of efficient catalysts with enhanced adsorption capacity and photocatalytic activity.

Photoelectrocatalysis (PEC) is a promising method for contaminant treatment, the preparation of photoelectrocatalyst is momentous for realization of superior PEC degradation efficiency. Herein, sulfur-doping g-CN and oxygen vacancy regulated bismuth molybdate heterojunction Sg-CN1/BMO5 was synthesized for chloroquine phosphate (CQ) degradation. Benefiting from band gap re-building and enhanced electronic transmission, the heterojunction displayed outstanding photoelectrocatalytic ability, and 90.2% of CQ can be degraded within 120 min. The degradation activity of Sg-CN1/BMO5 has been testified by pseudo-first-order rate constant, which was 3.03 and 2.66 folds of g-CN and BM. The enhanced photoelectrocatalytic effect was attributed to the boosted visible light adsorption ability, recombination suppression of photogenerated carriers and accelerated charge transfer process of the heterojunction. Radical capture experiments and electron spin-resonance (ESR) results revealed that the hydroxyl radical (•OH), superoxide radical (•O2-) and hole (h+) dominated the CQ degradation. Furthermore, the CQ degradation pathway and toxicity evaluation of intermediates were proposed based on DFT calculation and LC-MS identification.

Developing functional adsorption materials that efficiently adsorb high viscosity oil is crucial for solving oil spill accidents. Herein, low-density three-dimensional porous melamine sponge was used as the modified substrate. First, phytic acid is selected for modification to make it flame retardant. Then, polypyrrole (PPy) and hexadecyltrimethoxysilane (HDTMS) are modified on its surface through low-temperature polymerization and impregnation, ultimately obtaining a multifunctional durable superhydrophobic PA/PPy/HDTMS@MF (melamine foam) sponges with photo/electro-thermal effects and flame retardant. When the applied voltage is 10 V, the core temperature on the PA/PPy/HDTMS@MF sponge’s surface rapidly increases from 26.4 °C to 134.6 °C within 80 seconds, and the sponge will not burn and be damaged. Under the irradiation of one sunlight (1 kW/m2), the surface core temperature can rapidly rise from 26.4 °C to 93 °C within 70 seconds. The superhydrophobic PA/PPy/HDTMS@MF sponge can all-weather absorb kinds of high viscosity crude oil and solid oils that are 18-27 times than its own mass, indicating that the prepared superhydrophobic sponge has excellent oil collection performance. And under one sunlight (1 kW/m2), after 10 cycles of desorption, the prepared superhydrophobic sponge can still absorb 26 times more crude oil than its own weight. In addition, PA/PPy/HDTMS@MF sponge also has the characteristic of photothermal defrosting and deicing, and the ice on its surface can begin to melt within 5 min under one sunlight (1 kW/m2). The melted water will not enter the inside of the sponge, effectively ensuring the utilization efficiency of photothermal effects. Based on the above advantages, the prepared photo/electro thermal conversion superhydrophobic sponge has excellent development prospects in the field of high viscosity oil adsorption and photothermal defrosting/deicing.

Radiocesium (Cs+) treatment is getting more attention as Japan plans to dump wastewater from Fukushima nuclear meltdown into the Pacific Ocean. Prussian blue is a star material and medicine for intracellular and extracellular therapy of Cs+. However, it and its analogues are essentially unstable in alkali-solution and seawater due to break down easily into the hazardous cyanide substance. In this study, copper ferrocyanide/magnetic montmorillonite composites (KCuFC/M−MT) were prepared using an in-situ synthetic method. This method can inhibit the decomposition of Prussian blue analogues (PBAs) and the production of toxic cyanide. The 5KCuFC/M−MT composites exhibit excellent Cs+ adsorption properties (204.48 mg/g), good material chemical stable over a wide pH region (2 ≤ pH ≤ 12), safe amount of cyanide release (<0.2 mg/L, EPA, USA), and low-toxic to human hepatocytes (HepG2 cells), which are promising for the application in radioactive wastewater treatment. The adsorption mechanism and stabilization mechanism were systematically studied. This study provides a reference for the control radioactive Cs+ hazards by using clay material stabilized ferrocyanide material and provides a new direction for the research of cesium-control materials. This research solves the problem of basic instability of PBAs and expands new application fields for PBAs, especially decorporation agent for internal contamination by radiocesium.

In this work, perborate (BO3−) was applied to promote the degradation of sulfadiazine (SDZ) in copper-immobilized carbon nanofibers (Cu-CNF-x) activated peroxymonosulfate (PMS) system. Results showed that in BO3−/Cu-CNF-3/PMS ternary system, 100% of SDZ (40 μM) could be efficiently eliminated in 5 min with 0.1 g/L Cu-CNF-3, 1 mM BO3− and 1 mM PMS; while Cu-CNF-3/PMS and BO3−/PMS systems only achieved 58.4% and 47.3% degradation in 30 min. In initial pH range of 5.0–9.0, the ternary system removed over 92.6% of SDZ, and the treated solution pH maintained neutral, effectively relieving the water acidification introduced by PMS. Electron paramagnetic resonance analysis and radical scavenger tests evidenced the production of SO4−•, •OH, 1O2 and H2O2BO•O•−. Mechanisms analysis proposed the activation process as follows: initially, BO3− promptly activated PMS to generate H2O2BO•O•− via electrophilic substitution reaction, and H2O2 was produced due to the decomposition of BO3−; thereafter, PMS was activated by Cu-CNF-x to yield SO4−•, •OH and 1O2; the obtained H2O2 was then utilized by Cu-CNF-x to produce •OH and 1O2 as well. Density functional theory (DFT) calculations showed that the adsorption energy (Ead) between PMS and Cu-CNF-x was 0.43 eV. BO3− greatly increased the Ead of PMS on Cu-CNF-x by ten times to 4.75 eV, which extremely promoted the PMS activation. This work provided a novel strategy of BO3−/Cu-CNF-3/PMS for the efficient degradation of refractory organic pollutants, and managed to understand the synergistic role of BO3− to PMS based heterogeneous catalytic processes.

The commercial demand for D2 is poised to increase significantly; however, the low natural abundance and the energy- and capital-intensive industrial separation (i.e., 24 K cryogenic distillation) will hamper future scientific and industrial growth in isotopologue separation. Alternatively, kinetic quantum sieving (KQS)-based adsorptive D2 separation has been proposed recently, but the separation performance is reported mostly at near zero pressure or in the sub-few ten mbar range. Herein, an Al-based Metal-Organic Framework, MOF-303, with 1-D narrow-micro pores is studied for D2/H2 adsorptive separation at ambient pressure. Cryogenic thermal desorption spectroscopic analysis of MOF-303 confirmed that the synergetic effect of binding affinity & enhanced KQS (owing to molecular rearrangement of D2 adsorbed phase at high pressure induced by strong D2 confinement), along with D2 partial condensation, leads to a significant increase in the D2 uptake with increasing exposure pressure up to 1,000 mbar. Consequently, a remarkable selectivity of 21.6 at 25 K has been achieved even at an operating pressure of 1000 mbar, which is an industry-friendly condition. The observed D2/H2 separation selectivity is about ten times higher than that of the industrial cryogenic method (best selectivity of below 2.5 at 24 K), and comparable to the performance of the adsorbent materials already reported with low operating pressure, making adsorptive D2/H2 separation through MOF-303 an alternative for cryogenic industrial isotopologue separation.

In this study, a series of ZnO decorated rGO composites (x%ZnO@rGO) were successfully synthesized by the alkaline hydrothermal method. The crystal structure, surface morphology, and chemical property of x%ZnO@rGO were characterized by BET, XRD, FT-IR, SEM, TEM, and XPS, respectively. Amongst, 15%ZnO@rGO composite exhibited superior catalytic ozonation performance with an improvement of 68.4% on atrazine (ATZ) degradation efficiency (3 mins), more than 7.8 times of the pseudo-first-order rate constant compared with single O3. The roles of O3 and reactive oxygen species (ROSs) were confirmed and compared by the quenching and low-concentration probe experiments, suggesting that O3 and OH played an important role for ATZ degradation, while the function of 1O2 and O2− can be neglected both in single O3 and 15%ZnO@rGO/O3 system, which was contrary to that of the quenching experiments. Besides, the exposures of O3 and ROSs showed that 15%ZnO@rGO can facilitate the transformation process of 1O2 to OH in different conditions, and largely enhance the exposure of OH. The roles of electrons, Lewis acid sites, and oxygen vacancies of 15%ZnO@rGO in catalytic ozonation were identified as well, which offered us a new perspective to design a high-efficiency catalyst and may promote graphene-based metal oxides for practical pollutant elimination.

Microbubble ozonation combined with electro-generated H2O2 process (EH2O2-MB-O3) was applied to degrade ciprofloxacin (CIP) as a typical antibiotic in wastewater in this study. The results showed that the performance of CIP degradation and mineralization in EH2O2-MB-O3 process was more efficient than other related processes. Microbubble ozonation and electro-generated H2O2 showed obvious synergistic effect on enhanced CIP removal in EH2O2-MB-O3 process. The O3 dosage, applied current and initial pH in EH2O2-MB-O3 process were optimized as 12.5 mg/min, 50 mA and 7.0 (uncontrolled). Under the optimal conditions, CIP could be degraded completely within 60 min and the TOC removal efficiency of 28.85% could be achieved within 90 min in EH2O2-MB-O3 process. The corresponding ozone utilization efficiency was close to 100%. More efficient ROS generation was observed in EH2O2-MB-O3 process, especially •OH, compared with other related processes. The contribution rates of •OH, 1O2, O3 and O2.- to CIP removal were determined as 66.79%, 23.57%, 6.67% and 2.98% in EH2O2-MB-O3 process, respectively. The electro-generated H2O2 was clarified to contribute to not CIP removal but ROS generation. Three CIP degradation pathways were proposed according to identified degradation intermediates, which indicated that pyridone structure of quinoline and piperazine ring in CIP molecule could be destroyed more easily than benzene ring of quinoline, and the hydroxylation seemed to prevail in these CIP degradation pathways due to •OH electrophilic addition reaction probably. The removal of other antibiotics in EH2O2-MB-O3 process also depended on not ozone direct oxidation but •OH oxidation mainly.

In this study, trisurethane modified sulfonamide based polymeric adsorbent was prepared starting from reaction with chlorosulfonated poly (styrene) (PS) beads and tris(hidroxymethyl) aminometane. Hydroxyl functions of the adsorbent were reacted with butyl isocyanate in the presence of dibutyltin dilaurate as a catalyst at 60 0C for 48 h to obtain tris urethane functional polymeric adsorbent (PS-TUR). Spectroscopic and morphological characterizations of the polymeric adsorbents were carried out using scanning electron microscopy (SEM-EDX), infrared spectrophotometry (FTIR), XPS and analytical methods.The surface properties of PS-TUR were investigated for the first time with the inverse gas chromatography technique at infinite dilution before adsorption studies. The dispersive surface energy of adsorbent was determined according to the method of Schultz (55.54–61.73 mJ m−2) and Dorris-Gray (57.70–67.03 mJ m−2). Adsorption enthalpy and Gibbs free energy were calculated according to this technique and it was determined that the adsorption was exothermic and spontaneous. As a result of the analyzes made with this technique, it was determined that the PS-TUR adsorbent surface was acidic (KD/KA=0.27<1) and optimum conditions (pH: 7, dose: 0.10 g) were determined for the effective adsorption of Hg (II) ions. Surface acidity-basicity behavior of sorbent was determined by isoelectric point (IEP: 6.20) and pHpzc (5.81) analyses.Batch adsorption studies of the PS-TUR adsorbent were carried out as a function of adsorbent dosage, pH, initial metal ion concentration (0.0025–0.1000 mol/L), and kinetically. After determination of optimum adsorbent dosage was found as 100 mg, mercury sorption capacity of PS-TUR adsorbent was found as 511.50 mg g−1 adsorbent.Desorption studies were carried out using glacial acetic acid and studies demonstrated that PS-TUR adsorbent is regenerable and can be successfully used for four adsorption–desorption cycles without significant loss its capacity.Also, PS-TUR adsorbent shows selectivity with high sorption capacity towards mercury as compared to other metal ions.

Herein, the preferential leaching of Li and Ni from spent lithium-ion batteries was put forward for the first time. Firstly, the stable structure of cathode material was destroyed by reduction roasting, and then Li and Ni in roasted product were leached in sodium persulfate solution. Through adjusting the redox potential and pH of the solution, Li and Ni could exist in the solution in the form of Li+ and Ni2+, while Co and Mn remained in the residue mainly in the form of Co3O4 and MnO2. The leaching efficiencies of Li and Ni were 95.07% and 96.02% under the optimized conditions, respectively. Kinetic analysis showed that the leaching process was controlled by surface chemical reaction. In addition, XPS, XRD, thermodynamic analysis, and SEM-EDS were used to explore the mechanism. This method could effectively simplify the recovery and separation process, providing a new thought for the utilization of spent lithium-ion batteries.

The construction of high-performance oxygen evolution reaction (OER) electrocatalysts is crucial for energy applications. Here, we demonstrate a reliable route to incorporate iridium (Ir) into cobalt (Co)-based hydroxide derived from ZIF-67 on the surface of Ni-contained carbon nanofibers (denoted as Ni-CNFs/Ir-Co(OH)2) as an electrocatalyst to boost its alkaline OER property. The optimized Ni-CNFs/Ir-Co(OH)2 sample exhibits an extraordinary OER activity with an overpotential of only 240 mV to reach 10 mA cm−2, much lower than that of commercial IrO2 electrocatalyst (331 mV). The theoretical results illustrate the highly active Co sites of Iredge-Co(OH)2 for OER. Furthermore, the distinct nanofibrous architecture of Ni-CNFs endows with a desirable electrical conductivity of the catalyst, thus the Ni-CNFs/Ir-Co(OH)2 sample presents a desirable durability for OER testing. In addition, a total water electrolyzer is built by using the prepared Ni-CNFs/Ir-Co(OH)2 and Pt/C as electrodes, which requires only 1.50 V at 10 mA cm−2, superior to the value of Pt/C||IrO2 cell (1.62 V). This study puts forward an effective route to explore superior OER electrocatalysts by engineering the electronic structure of metal hydroxide for energy applications.

Magnetic biochar is an efficient peroxymonosulfate (PMS) catalyst with high potential for industrial applications. However, the effects of phosphate on the active sites of magnetic biochar and oxidative species remain controversial. In this study, Enteromorpha-derived magnetic biochar was prepared for the activation of PMS. Results found that CO, COOH, defects, graphite N, Fe2+, and Fe0 were the main active sites in the magnetic biochar/PMS system. The presence of monohydrogen phosphate (HPO42−) had no effect on the activation of PMS. However, the existence of dihydrogen phosphate (H2PO4−) had a significant inhibitory effect and affected the production of free radicals, which was ascribed to the shielding effect of H2PO4− on graphite N, CO, COOH, Fe2+, and Fe0 active sites. Overall, this study provides insight into the main reaction mechanisms of PMS activation by magnetic biochar with co-existing phosphates, facilitating the application of magnetic biochar for practical wastewater purification in persulfate oxidation systems.

The current study delves into the emerging realm of growing ferrites of bismuth, cobalt, and nickel on the surface of cationic ion exchanger Amberlyst-15. To evaluate the effect of surface modification, bare Amb-15 was also used for the comparative study for the removal of Cd+2 ions. The surface charge, phase identification, surface area, pore size distribution, desired functionalities, morphology, and composition of the bare and modified sorbents were evaluated via an array of analytical techniques. The efficacy of each adsorbent was investigated under the influence of contact time, temperature, adsorbents dosage, and concentration of adsorbate. The results showed that modified sorbents have remarkable removal efficiency of Cd+2 from 80 to 91 %. The adsorption of Cd+2 ions followed Langmuir and pseudo second order kinetic model indicating the physiochemical nature of the sorption process. The maximum sorption capacity (qm) of 21.79 mg/g, 32.37 mg/g, 304.87 mg/g, and 221.23 mg/g was obtained for Amb-15, Amb@BFO, Amb@CFO, and Amb@NFO respectively. Additionally, a desorption study was also carried out and the findings showed that modified adsorbents follow the 3Rs (reusability, recyclability, and regeneration). Among the contenders, Amb@CFO showed the best response toward the uptake of Cd+2 ions.

In this study, we dexterously constructed a unique in situ interface oxidation–adsorption dual-reaction platform through the self-excitation of ferrate (Fe(VI))/peroxymonosulfate (PMS) for phenylarsonic acid (PAA) and inorganic As(V) removal. When the molar ratio of Fe(VI)/PMS was 1:2, 80% degradation of PAA could be achieved within 180 min and the apparent constant value of the reaction rate (kobs) would reach up to 0.185 min−1. 1O2 and Fe(IV) were the main active species for degradation of PAA in Fe(VI)/PMS reaction system. In addition, we explored the possible degradation intermediates and pathway of PAA. In situ Fe(III) oxides generated from Fe(VI) decomposition could adsorb arsenic pollutants through ligand exchange with inorganic As(V) through surface hydroxyl groups to form Fe-O-As bonds. The effect of coexisting anions on the removal performance of the system was investigated, and the results showed that the presence of PO43− and CO32− promoted the oxidative degradation of PAA owing to the activation of PMS by PO43− and CO32−, but Cl− can inhibit the PAA degradation through a free radical scavenging mechanism. PO43− and SiO32− affected the adsorption and removal of the released inorganic As(V) due to their competitive adsorption of in situ generated Fe(III) oxides. Density functional theory (DFT) calculations indicated an obvious electron transfer (1.83 e) between the in situ generated Fe(III) oxides and inorganic As(V) with a high adsorption energy of −10.30 eV. These results indicate that the combination of Fe(VI) and PMS can effectively control the total arsenic in water bodies.

Although recycling retired lithium-ion batteries (LIBs) can alleviate global warming and the energy crisis, the environmental impacts of different recycling routes require further assessment. The multiple environmental indicators, such as carbon footprint and cumulative energy consumption for three hydrometallurgical recycling and remanufacturing routes of LIBs in China are quantified and compared using life cycle assessment methods. Then, the potential of reducing environmental impacts by battery remanufacturing with recycled materials is assessed. Moreover, the sensitivity of battery recycling and remanufacturing to temporal and geographical variations in electricity generation is determined. Results reveal that: (1) Differences in chemical reagents, energy consumption, and processes lead to differences in environmental indicators of battery recycling, with a gap of up to 29.3 kg CO2 eq./kWh in carbon footprint. (2) Due to avoiding raw material mining and processing, battery manufacturing with recycled materials can reduce the endpoint environmental categories by more than 18.4% compared to that with raw materials. (3) The environmental impacts of LIBs remanufacturing through a multi-recycling-approach will gradually decrease and reach to a constant, with the lowest carbon footprint of this route being only 61.1 kg CO2 eq./kWh. (4) The carbon footprint of LIBs manufacturing in China in 2050 can be more than 37.5% lower than that in 2021. Battery recycling and decarbonization of energy systems can reduce environmental impacts and contribute to the sustainable development of the transportation industry.

Peroxymonosulfate (PMS)-based advanced oxidation processes have become promising water treatment technologies in recent years. The redox cycle between transitional metals in heterogeneous catalysis is essential for continuous activation of PMS and efficient removal of pollutants. In this work, we prepared Fe3O4 using precipitation method and subsequently added Ni aqueous solution to synthesize Ni-Fe (hydr)oxides. Ni-Fe (hydr)oxides show efficient PMS activation ability, causing the degradation of 96.8% trichloroethylene (TCE) after 40 min with the dosage of Fe, Ni and PMS at 0.2, 0.1 and 0.2 mM, respectively. The catalyst concentration normalized TCE degradation rate constant of Ni-Fe (hydr)oxides/PMS system reaches 1.48 L g−1 min−1. Nonradical pathway is dominant at the initial stage of the reaction which generates high-valent metals, SO5•− and indirectly produces 1O2. 1O2 and dissolved O2 together participate in the O2 cycling, •OH generation, and electron transfer involving the reduction of trivalent metals. Divalent metals react with PMS to generate strong oxidative •OH and SO4•− through radical pathway in later stage. TCE is degraded and dechlorinated by multiple reactive species in Ni-Fe (hydr)oxides/PMS system. The optimum Ni/Fe ratio of catalysts under the studied conditions was 0.50. Ni-Fe (hydr)oxides show high reactivity and stability in real water matrices, demonstrating Ni-Fe (hydr)oxides are promising catalysts for PMS activation to degrade pollutants in contaminated water.

The nano/micro-sized catalysts for peroxymonosulfate (PMS) activation often undergo agglomeration, leading to inevitable loss of active sits and reduced catalytic efficiency. Herein, monolith nickel foam (NF) supported ZnCo2O4 nanosheets were constructed, achieving almost complete removal of ciprofloxacin (CIP) within 15 min. ZnCo2O4@NF exhibits prominent stability in microstructure and exposed active sites, resulting in high reusability. The unique Zn-O-Co structure and “conducting bridge” of NF could accelerate the electron transfer from ZnCo2O4 to PMS and the following O-O bond cleavage. This facilitates Co2+/Co3+ redox cycle for continuous SO4•− generation and endows ZnCo2O4@NF with low reaction barrier. The surface hydroxyl groups and the inner-sphere complexation between PMS and catalyst play significant role in the formation of reactive oxygen species (ROS). Furthermore, the quenching test confirmed the dominant role of SO4•− and auxiliary role of •OH/1O2 in ZnCo2O4@NF/PMS system. The reaction sites in CIP molecule easily attacked by ROS were determined, and the possible radical/non-radical degradation pathways of CIP were proposed. This work further unveiled the mechanism of the covalency and electronic configuration in ZnCo2O4@NF. The distinct advantages of the macroscopic catalyst including outstanding catalytic ability and high structural stability provide great possibility for broad industrial application.

The continuous increase in carbon dioxide emissions into the atmosphere necessitates the exploration of new, efficient, and environmentally friendly systems for CO2 capture. Deep eutectic solvents (DESs), known for their unique physicochemical properties, have shown promising potential for replacing traditional absorbents due to their strong CO2 absorption capacity. In this study, we propose a two-step screening process, employing a data-driven approach, to design novel DESs as CO2 absorbents.At the initial screening stage, machine learning methods were used to develop models capable of predicting the CO2 absorption capacity of DES. To enhance the chemical diversity within the training set, we combined data on the CO2 absorption capacity of DESs (162 structures) and ILs (232 structures). Among the models developed, two demonstrated superior performance. The first one, called transformer convolutional neural fingerprint (TransCNF), and the second one, Random Forest (RFR) with extended connectivity fingerprint (ECFP), outperformed the others.To gain insights into the RFR/ECFP model, we employed the SHAP method and identified 30 significant descriptors. By comparing the contributions of these descriptors with the experimental observations, we found that the developed model accurately represented the influence of the structure of DESs on their CO2 absorption capacity. Thus, the model exhibited reliable performance.At the second stage of the screening process, we employed the Redlich-Kister thermodynamic model together with the machine learning model to predict the melting temperature of the DESs. Based on the screening results, we found that 1447 DESs with high CO2 absorption ability remained liquid at room temperature, which made them promising candidates for CO2 capture.

Preparation of efficient adsorbents is of great significance for the recovery of precious metals from secondary resources. Herein, –NH2 was successfully grafted on MIL-101(Cr) via hydrothermal reaction to improve the adsorption capacity of Au (Ⅲ) in aqueous solution. MIL-101(Cr)–NH2 had a huge specific surface area (1016.50 m2‧g−1), which can provide more adsorption sites for Au (III). At 298 K, the maximum adsorption capacity of Au (III) by MIL-101(Cr)–NH2 was 792.43 mg∙g−1 and was higher than that by MIL-101(Cr) (140.83 mg∙g−1). The adsorption data was well fitted by Langmuir and pseudo-second-order models, confirming that the adsorption process conformed to single molecule adsorption and chemical adsorption. Mechanism study indicated that the adsorption of Au (III) by MIL-101(Cr)–NH2 was initiated with electrostatic attraction and promoted by reduction and inner complexation between AuCl4- and protonated amino groups. During adsorption, Au (Ⅲ) was reduced to Au (0) and Au (I) by –NH2. Density functional theory (DFT) calculation demonstrated that MIL101(Cr)–NH2 possessed higher binding affinity and more adsorption sites for Au (III) than MIL-101(Cr). Moreover, MIL-101(Cr)–NH2 exhibited excellent selectivity towards Au (III) and good recyclability, which is promising in the recovery of precious metals.

Heterojunction coupling with narrow bandgap semiconductor can effectively promote light absorption, inhibits photoinduced carrier recombination and enhances redox performance. Herein, a novel Ce2S3 nanocube was synthesized via a high-temperature sulfating method, then ZnxCd1-xS (ZCS) was grown on Ce2S3 cube to form a tight junction for the photocatalytic hydrogen evolution (PHE) activity. The experimental results confirm that this novel composite vastly boosts the redox performance due to superior visible light absorbance, narrow bandgap and fast charge carrier separation via a Z-scheme mechanism. Consequently, the optimized Ce2S3/ZCS composite presents the best PHE rate of 35.35 mmol h−1 g−1 without an obvious reduction in efficiency for cycling experiments, which has a 4.8-fold increase over Pt/ZCS. This strategy proposes a novel method for optimizing ZCS-based photocatalysis by introducing Ce2S3 component to improve the property of PHE.