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Molybdenum disulfide (MoS2), a typical two-dimensional transition metallic layered material, attracts tremendous attentions in the electrochemical energy storage due to its excellent physicochemical properties. However, with the deepening of the research and exploration of the lithium storage mechanism of these advanced MoS2-based anode materials, the complex reaction process influenced by internal and external factors hinders the exhaustive understanding of the lithium storage process. To design stable anode material with high performance, it is urgent to review the mechanisms of reported anode materials and summarize the related factors that influence the reaction processes. This review aims to dissect all possible side reactions during charging and discharging process, uncover internal and external factors inducing various anode reactions and finally put forward strategies of controlling high cycling capacity and super-stable lithium storage capability of MoS2. This review will be helpful to the design of MoS2-based lithium-ion batteries (LIBs) with excellent cycle performance to enlarge the application fields of these advanced electrochemical energy storage devices.

Molybdenum disulfide (MoS2) with low cost, high activity and high earth abundance has been found to be a promising catalyst for the hydrogen evolution reaction (HER), but its catalytic activity is considerably limited due to its inert basal planes. Here, through the combination of theory and experiment, we propose that doping Ni in MoS2 as catalyst can make it have excellent catalytic activity in different reaction systems. In the EY/TEOA system, the maximum hydrogen production rate of EY/Ni-Mo-S is 2.72 times higher than that of pure EY, which confirms the strong hydrogen evolution activity of Ni-Mo-S nanosheets as catalysts. In the lactic acid and Na2S/Na2SO3 systems, when Ni-Mo-S is used as co-catalyst to compound with ZnIn2S4 (termed as Ni-Mo-S/ZnIn2S4), the maximum hydrogen evolution rates in the two systems are 5.28 and 2.33 times higher than those of pure ZnIn2S4, respectively. The difference in HER enhancement is because different systems lead to different sources of protons, thus affecting hydrogen evolution activity. Theoretically, we further demonstrate that the Ni-Mo-S nanosheets have a narrower band gap than MoS2, which is conducive to the rapid transfer of charge carriers and thus result in multi-photocatalytic reaction systems with excellent activity. The proposed atomic doping strategy provides a simple and promising approach for the design of photocatalysts with high activity and stability in multi-reaction systems.

The good performance of base metal catalysts for the electrooxidation of organic pollutants has attracted great attention. However, base metal phosphides for electrooxidation are seldom studied owing to the sluggish water adsorption and dissociation dynamics, which will hinder the production of the sorbed hydroxyl radicals (M(•OH)) and thus inhibit the electrooxidation of organic pollutants. Herein, we proposed a universal strategy to improve the electrooxidation capability of metal phosphides by modulating the surface electron densities. The electron interactions between cobalt (Co) and phosphorus (P) are modulated after iron doping, resulting in more positively charged Co and more negatively charged P, which can promote the adsorption and activation of water molecules and produce large quantities of M(•OH). Meanwhile, the experimental results show that the iron-modulated Fe0.53Co0.47P nanosheet arrays exhibit higher removal efficiency of tetracycline than the boron-doped diamond and Pt anode at low current intensity. Based on experimental results and density functional theory + U calculations (DFT + U), it is found that Fe0.53Co0.47P has lower barrier (0.45 eV) to form the sorbed hydroxyl radicals (M(•OH)) and higher overpotential to produce O2 than its counterparts, suggesting that Fe0.53Co0.47P can produce more M(•OH) instead of O2. The above results highlighted the feasibility of these base metal phosphides for electrooxidation for advanced water purification.

Benzophenone derivatives, including benzophenone-1 (C13H10O3, BP1), benzophenone-3 (C14H12O3, BP3) and benzophenone-8 (C14H12O4, BP8), that used as UV filters are currently viewed as emerging contaminants. Degradation behaviors on co-exposure benzophenone derivatives using UV-driven advanced oxidation processes under different aqueous environments are still unknown. In this study, the degradation behavior of mixed benzophenone derivatives via UV/H2O2 and UV/peroxydisulfate (PDS), in different water matrices (surface water, hydrolyzed urine and seawater) were systematically examined. In surface water, the attack of BP3 by hydroxyl radicals (HO∙) or carbonate radicals (CO3∙-) in UV/H2O2 can generate BP8, which was responsible for the relatively high degradation rate of BP3. Intermediates from BP3 and BP8 in UV/PDS were susceptible to CO3∙-, bringing inhibition of BP1 degradation. In hydrolyzed urine, Cl− was shown the negligible effect for benzophenone derivatives degradation due to low concentration of reactive chlorine species (RCS). Meanwhile, BP3 abatement was excessively inhibited during co-exposure pattern. In seawater, non-first-order kinetic behavior for BP3 and BP8 was found during UV/PDS treatment. Based on modeling, Br− was the sink for HO∙, and the co-existence of Br− and Cl− was the sink for SO4∙-. The cost-effective treatment toward target compounds removal in different water matrices was further evaluated using EE/O. In most cases, UV/H2O2 process is more economically competitive than UV/PDS process.

Structural modulation of catalytic nanostructures and fundamental understanding of their active sites at the atomic scale are important for predicting and improving the catalytic properties of nanostructures. Here, we prepared quasi-one-dimensional (1D) metal molybdenum (Mo) chains confined in atom-thick molybdenum disulfide (MoS2), referred henceforth as Mo/MoS2 nanosheets, and evaluated their hydrogen evolution reaction (HER) properties. The experiment and theoretical calculations show that the quasi-1D Mo chain with unsaturated coordination exhibits high HER activity. The unsaturated Mo sites in the chains increase the carrier density and facilitate the diffusion of hydrogen along the chains, mimicking an atomic scale reactor which leads to an experimentally observed enhanced catalytic performance. Within the framework of Volmer-Tafel model, the calculated kinetic barrier for H2 evolution is only 0.48 eV for Mo/MoS2, which is significantly lower than that for the Pt (111) surface (∼0.8 eV). In particular, Mo/MoS2 nanosheets supported on reduced graphene oxide (Mo/MoS2/RGO) outperformed commercial Pt on glassy carbon (Pt/C) in the practically meaningful high-current region (>140 mA cm−2) in 0.5 M H2SO4 solution and (15 mA cm−2) in 1.0 M NaOH solution, demonstrating that the Mo/MoS2/RGO could potentially replace Pt catalysts in practical HER systems. Additionally, this study provides crucial insights into the role of active centers in catalysis through a model-structure-performance relationship, thus pointing the way to a commercially viable technology for HER.

Water pollution caused by heavy metal and organic pollutant becomes a rigorous problem, thereby a clean and sustainable technology should be developed to resolve this situation. In this work, a novel AgI/Bi24O31Cl10 Z-scheme photocatalysis system was designed to overcome this problem. The prepared AgI/Bi24O31Cl10 composite was characterized by many means such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET). The designed Z-scheme photocatalysis system conquers difficulties of traditional photocatalysts of the fast photogenerated charge carrier recombination and weak redox ability, thereby held remarkable catalytic activity for Cr (VI) reduction and tetracycline (TC) oxidation, approximately 85.36% and 78.26% of tetracycline and Cr (VI) can be removed under visible light illumination for 1 h. Some factors like contaminant concentrations, inorganic cation, inorganic anion, and water resources on catalytic activity were explored and the influence mechanism was discoursed. Importantly, the cyclic experiment suggested that the removal efficiency did not have obvious loss after five consecutive experiments, confirming its stability and reusability. The photodegradation pathway of TC was also proposed according to liquid chromatography-mass/mass spectrometry (LC-MS) and three dimensional excitation-emission matrix fluorescence spectra (3D EEMs). Furthermore, this Z-scheme photocatalysis mechanism for Cr (VI) reduction and TC oxidation was proposed based on trapping experiment and electron spin resonance (ESR) measurement. This study sheds lights on the design of Z-scheme photocatalysis system with sunlight as driving force for refractory organic pollutants removal.

Metallic 1T phase molybdenum disulfide (1T-MoS2) holds great promise in energy storage applications due to its excellent conductivity and hydrophilicity. However, free 1T-MoS2 nanosheets are prone to agglomeration and convert to 2H-MoS2, resulting in a decrease in electrochemical performance. In this study, metallic 1T phase MoS2 nanosheets are confined among TiO2 nanotube arrays (1T-MoS2@TiO2/Ti) via a facile hydrothermal process. The architecture in the glory of ultrathin 1T-MoS2 nanosheets and highly ordered pore tunnel of TiO2 nanotube arrays benefits fast electrolyte diffusion and electron transfer. As a result, the 1T-MoS2@TiO2/Ti composite shows a high specific capacitance of 428.1F g−1 at 0.2 A g−1, high energy density of 48.2 Wh kg−1, high power density of 2481.7 W kg−1 and 97% capacitance retention after 10,000 cycles. This study proves an artful thought for designing electrode materials to enhance their electrochemical performances.

Hydrogenation engineering has been considered as one of the promising methodologies to significantly enhance the visible light absorption and photocatalytic activities of semiconductor photocatalyst. However, hydrogenated catalyst with remarkably elevated photocatalytic activity has been commonly obtained so far under severe conditions such as high temperatures or pressures and huge doses of H2 or plasma activation with complex treatment. Here, we proposed in-situ hydrogenated ZnIn2S4 (HxZIS) obtained at room temperature under UV–vis light illumination within several hours. This extremely facile hydrogenation strategy is based on the discovered fact that H could spontaneously adsorb on the ZnIn2S4 (ZIS) surface to generate durable point defects and even surface disorder, resulting in the largely enhanced solar energy utilization of ZIS. As a result, the hydrogenation engineered the band gap from 2.42 to 1.51 eV, while the optimal bandgap was tuned to ca. 2.08 eV with a ∼10-fold photocatalytic activity promotion. This study is the first paradigm of in-situ hydrogenation of inorganic metal chalcogenide, and we believe that such a facile and general methodology will open up a new pathway to create high-efficiency photocatalyst.

Heterogeneous photo-Fenton system is widely studied as a very promising water treatment technology. However, there are still some challenges, such as the recovery of solid catalysts, weak photo-Fenton activity at neutral pH and unclear mechanism of photo-assisted Fenton. Here, we demonstrated that hydrothermal synthesized pyrrhotite (SP) was a visible light photo-Fenton catalyst with excellent magnetic recovery performance toward the degradation of organic pollutants at neutral pH. The catalytic degradation performance of SP was 7.5 and 10 times that of natural pyrrhotite (NP) and commercial FeS (com-FeS), respectively. We found that the acid-base buffer function of SP composite was responsible for the photo-Fenton activity at neutral pH. Furthermore, we show that absence of atoms in SP, the formation of vacancies, are responsible for the excellent activity. Overall, this work provide new insight toward the understand of photo assisted Fenton mechanisms at neutral pH.

Two-dimensional (2D) layered transition metal sulfide based materials are promising candidates for electrodes of lithium ion batteries (LIBs). As one of the representatives, molybdenum disulfide (MoS2), exhibits additional reversible capacity beyond their theoretical value although the lithium storage mechanism is still poorly understood. In this report, we developed a highly conducting metallic phase 1T(octahedral)-MoS2 based electrode with metal Mo atoms confined in “graphene nanoreactor” of abnormal lithium-storage sites, which delivered a high specific capacity of ~1800 mAh g−1 at 1 A g-1, about 2.6 times of its intercalation reactions value. Contrary to previous reports, a new lithium-storage mechanism for the high and ever-increasing capacity was proposed. The theoretical calculations and experiments show that a major contribution to the extra capacity in MoS2 anodes is due to Mo atoms accommodate with Li+. The Mo precipitates and their full contact with Li2S matrix enabled the reversible Mo→LixMo→Mo→1T-MoS2 reaction during charging/discharging processes. Over prolonged cycling, per Mo atomic could accommodate six Li+ ions. This new proposal could help to establish an accurate electrochemical reaction mechanism of MoS2 LIBs, which may lead to inspiration on new methods to greatly improve the performance of the MoS2 anode.

Visible-light-driven photocatalysis has been widely employed as an efficient and environment-friendly technology for organic pollutants removal from wastewaters. Herein, a novel approach of BiVO4-catalyzed sulfite under visible light irradiation (BiVO4/sulfite/vis) was established to achieve the model contaminant methyl orange (MO) removal. About 92.06% of MO could be rapidly degraded within 50 min in this new catalytic system and the reaction rate was close to 105.29-fold as high as that of BiVO4/vis system. The effects of sulfite amount, catalysis dosage, MO concentration, inorganic anions and natural organic matters (NOMs) were deeply investigated and the correspondent mechanisms were also discussed. Interestingly, the coexisting Cr(VI) at certain concentration would accelerate MO removal and further demonstrated by phenol and atrazine degradation through the Cr(VI) + organic pollutants combined pollution system. The presence of HA in BiVO4/sulfite/vis also exhibited positive effects on the degradation of organic pollutants, attributable to more OH species generation. Three-dimensional excitation-emission matrix fluorescence spectra (3D EEMs) and liquid chromatography-mass spectrometer (LC-MS) were implemented to explore MO degradation pathway. The sulfite (SO3 −) generation was confirmed by active species trapping experiments and electron spin resonance (ESR), and N2 purging reaction was also carried out to exclude the oxidative species of SO3 −. The photoinduced holes played a direct role in the SO3 − generation and the OH radical also contributed. This study provides new thoughts to improve the photodegradation of multiple organic pollutants by the introducing of sulfite or sulfite/Cr(VI).

Exploring and designing an efficient and robust photocatalyst toward the degradation of organic pollutants under nature sunlight irradiation is a challenging research topic. The ability to maintain the photocatalytic activity in the entire daytime will be the ultimate goal for further widespread application of solar energy-driven semiconductor photocatalysis. Here, an all-day-active Z-scheme photocatalytic system is reported by employing Ag@AgI nanoparticles decorated Ag3PO4 cubes (C-Ag3PO4@Ag@AgI). By coupling the pronounced carrier separation as well as increased stability, the C-Ag3PO4@Ag@AgI is capable of performing efficient Rhodamine B (RhB) and bisphenol A (BPA) degradation under sunlight irradiation, and still persist noticeable activity when the light is very weak. The RhB (20 mg/L, 50 mL) can be completely degraded by C-Ag3PO4@Ag@AgI (30 mg) within 1 h with the average luminous power of 117.5 mW (3.14 cm2). Dramatically, the as-prepared samples can still maintain photocatalytic activity even in a cloudy day (0.2–6.7 mW). This work has offered a valuable concept of continuous pollutant removal under nature sunlight irradiation in the entire daytime, which may serve as a model system for the wide environment applications, such as the removal of low-level pollutants under weak light irradiation.

Molybdenum disulfide (MoS2) presents a promising catalyst to replace state-of the-art platinum (Pt) for hydrogen evolution reaction (HER), but it still lacks an effective way due to the catalytically inert basal plane. Herein, we report a rational design of MoS2 nanomesh that possesses evenly distributed holes and defects to make full use of the 2H-MoS2 basal planes by combining ball-milling with ultrasonic methods. The exfoliation of muti-layer MoS2 to fewer layer or enven monolayer is proceed in pure water without using any chemicals or surfactants. The great advantage of the catalyst is the monolayer, holey and defective structure, which maximizing the synergistic activity for both electrocatalytic and photocatalytic HER performances. Impressively, the MoS2 nanomesh renders outstanding electrocatalytic HER activity with an overpotential of 160 mV at a current density of 10 mV cm−2, and a small Tafel slope of 46 mV decade−1. The photocatalytic H2 evolution rate is about 4.84 mmol h−1 when working with Eosin Y as an organic photosensitizer. Additionally, this catalyst shows excellent cycle stability in the electrochemical and photocatalytic reactions. This present work put a new insight into the large-scale production of chemically active 2H MoS2-based catalysts for HER.

g-C3N4 has recently emerged as a promising photocatalyst for solar energy conversion. Nonetheless, attempts to enhance its inherently low activity are rarely based on precise molecular tunability strategy. In this study, two-type cyanamide defects-grafting g-C3N4 (CCN) was prepared through the thermal polymerization of thiourea in the presence of KCl. Stable potassium isothiocyanate (KSCN) was in situ generated via thiourea isomerization and then reacted with different amino groups ( NH2 and NH) in tri-s-triazine rings to obtain two-type cyanamide defects. Theoretical calculations and experiment results confirm that the ratio of the two-type cyanamide defects could be adjusted by KCl dosage, accompanying tunable energy levels of CCN. The charge carrier transfer and separation of CCN was greatly improved. Furthermore, the existence of cyanamide defects hindered the formation of intermolecular hydrogen bonds among g-C3N4, which facilitated the formation of porous structure and exposed more active sites for photocatalytic hydrogen evolution reaction (HER). As a result, the optimized photocatalyst (CCN-0.03) showed a high HER rate of 4.0 mmol g−1h−1, which was 5 times higher than 0.8 mmol g−1h−1 for pristine g-C3N4. And the apparent quantum efficiency reached up to 14.65% at 420 ± 10 nm. The findings deepen the understanding on precise molecular tuning of g-C3N4.

The capability of palladium (Pd) nanoparticles photo-deposited on BiVO4 (BV) nanosheets support to effectively activate persulfate (PS) and degrade pharmaceutical residues amiloride (AML) in aqueous solution under visible light was investigated. The removal efficiency of AML in Pd/BV/PS/vis system reached to 96.43% within 30 min as compared to only 50.73%, 70.87% and 77.70% in BV/vis, Pd/BV/vis and BV/PS/vis respectively under the identical experimental conditions. One inherent reason for the enhanced performance was possibly owing to the fact that visible light absorption of photocatalyst was improved through the surface plasma resonance (SPR) effect of Pd nanoparticles. For another respect, the photo-induced electron-hole pairs separation rate was firstly strengthened with Pd as electron traps and then by PS oxidants as electrons acceptors. Influencing factors including PS dosage, AML concentration, humic acid (HA) concentration, coexisting anions and cations and water sources on the AML degradation in the Pd/BV/PS/vis system were explored in details. Higher photocatalytic activity was still maintained in raw wastewater containing dyes, phenols and antibiotics. More generation of oxidative species such as O2−, OH and SO4 − were verified by radical quenching experiment and electron spin resonance (ESR) test. The major products of AML decomposition were identified and the correspondent degradation pathways were also proposed. This founding allows for the construction of highly efficient BV-based photocatalysts and provides a new opportunity for the treatment of wastewater containing refractory pollutants by SO4 −-based advanced oxidation processes (AOPs).

Using natural minerals as persulfate activators can develop effective and economical in situ chemical oxidation technology for environmental remediation. Yet, few natural minerals can provide a high activation efficiency. Here, we demonstrate that brochantite (Cu4SO4(OH)6), a natural mineral, can be used as a persulfate activator for the rapid degradation of tetracycline hydrochloride (TC-H). Approximately 70% of TC-H was removed in Cu4SO4(OH)6/PDS within 5 min, which much higher than that of Cu3P (61.99%), CuO (29.75%), CNT (25.83%), Fe2O3, (14.48%) and MnO2 (9.76%). Experiments and theoretical calculations suggested that surface copper acts as active sites induce the production of free radicals. The synergistic effect of Cu/S promotes the cycle between Cu+/Cu2+. Sulfate radicals and hydroxyl radicals are the main reactive oxygen species that are responsible for the rapid removal of TC-H. The findings of this work show a novel persulfate/brochantite system and provide useful information for the environmental remediation.

As a recent addition to the family of van der Waals layered crystals, indium selenide (InSe) possesses unique optoelectronic and photonic properties, enabling high-performance electronic devices for broad applications. Nevertheless, the lithium storage behavior of InSe flakes is thus largely unexplored due to its low electronic conductivity and challenges associated with its exfoliation. Here, we prepare few-layered InSe flakes through liquid-phase exfoliation of wet-chemistry-synthesized layered InSe single crystals, and percolate the flakes with carbon nanotube (CNT) networks in order to form flexible anodes to store lithium (Li). We demonstrate, with the support of CNTs, that exfoliated InSe flakes possess superior Li storage capacity to bulk InSe; the capacity increases over prolonged cycling up to 1224 mA h g−1 from 520 mA h g−1, coupled with excellent rate handling properties and long-term cycling stability. The operando X-ray diffraction results suggest that the alloying of indium with Li dominates the Li storage reactions. By combining with density-functional theory calculations and post-mortem analysis, we believe that the in situ formed indium gradually reduces the domain size, forming nanoclusters which allow the accommodation of 4 Li+ per atomic indium, and leading to extra capacity beyond the traditional theoretical value. This new “nanoscluster alloying” Li storage mechanism may inspire new architectures or methods to synthesize few-layered InSe, thereby presenting broad opportunities for high-performance Li-ion battery anode technologies.

Lithium–sulfur (Li–S) batteries have attracted great interest because of its high theoretical capacity (1675 mA h g–1). However, the low electrical conductivity of sulfur, dissolution of polysulfides, and structural collapse of electrode limit its practical application. Here an ultrathin honeycomb-like porous carbon derived from loofah sponge and doped with nitrogen (PCLSN) is prepared as a stable host for sulfur nanoparticles. Attributed to the integrated honeycomb structure, hierarchical porosity, ultrathin honeycomb walls, and synergistic effects between physical and chemical adsorption of polysulfides, the developed PCLSN@S cathode achieves a high initial specific capacity of 1379 mA h g–1 at 0.1 C, outstanding cyclability with a small capacity decay rate of 0.044% per cycle over 970 cycles at 2 C, excellent rate performance with a high capacity of 664 mA h g–1 at 3 C, and high sulfur content of PCLSN@S up to 76.1%. Our approach provides a promising route to design other 3D porous structures for high ...

Phenicol antibiotics (PABs) degradation by UV/H2O2 is important because we need to determine the reduction in toxicity and disinfection byproducts for post-chlorine. In this study, the degradation of PABs, including florfenicol (FLO), chloramphenicol (CAP) and thiamphenicol (THA), was examined. The pseudo-first order degradation rate constants of PABs were 3 times higher in ultrapure water (UW) than that in synthetic wastewater (SW) for these conditions: [PABs]0 = 1 μM, [H2O2] = 0.1 mM, and I0 = 1.985 × 10−6 E L−1 s−1. Fulvic acid (FA) and HCO3– inhibited PABs degradation, Cl− and NO3– concentrations of up to 5 mM and 10 mM had a negligible impact. The impact of water matrix on PABs degradation was successfully predicted using pseudo-steady-state kinetic model. The degradation of PABs was triggered via hydroxylation and/or hydrogen abstraction. The treatment of PABs via UV/H2O2 could decrease their antimicrobial properties, while the byproducts of FLO and THA showed higher acute toxicity in Vibrio fischeri. In addition, two identification products (TP-276 and TP-354) of FLO had higher ecotoxicity toxicity (using ECOSAR) in fish, daphnid and green algae. The trichloromethane formation potential (TCMFP) for PABs with post-chlorination in UW and SW can be reduced after UV/H2O2 compared to UV, and is related to the corresponding decrease of dissolved organic carbon (DOC).

Aluminum (Al) based rechargeable batteries offer the possibilities of safety, high energy density and low cost. Graphene with excellent mechanical properties and high electronic conductivity contributes to the excellent long-term cycle stability and superior rate performance, rendering it an attractive cathode material for Al batteries. However, the synthesis process of the high quality graphene, which is high energy consumption and complex, is not appropriate for the mass application of Al batteries. In this work, we presented a cost-effective and low-temperature (600 °C) synthesis of edge-rich graphene paper for the cathode of Al batteries. The edge-rich and interconnected design of graphene could effectively improve its performance in Al batteries. A reversible capacity as high as 128 mA h g−1 was achieved at 2000 mA g−1. It also displayed a superior cycling stability, displaying no capacity decay and a Coulombic efficiency higher than 99.2% after 20,000 cycles at even a high current density of 8000 mA g−1. Significantly, this novel cathode material would present a new opportunity for the practical application of Al batteries.

Photocatalytic degradation is an alternative method to remove pharmaceutical compounds from water, however it is hard to achieve efficient rate because of the low efficiency of photocatalysts. In this study, an efficient Z-Scheme photocatalyst was constructed by integrating graphitic carbon nitride (CN) and reduced graphene oxide (rGO) with AP via a simple facile precipitation method. Excitedly, ternary AP/rGO/CN composite showed superior photocatalytic and anti-photocorrosion performances under both intense sunlight and weak indoor light irradiation. NOF can be completely degraded in only 30 min and about 85% of NOF can be mineralized after 2 h irradiation under intensive sunlight irradiation. rGO could work not only as a sheltering layer to protect AP from photocorrosion but also as a mediator for Z-Scheme electron transport, which can protect AP from the photoreduction. This strategy could be a promising method to construct photocatalytic system with high efficiency for the removal of antibiotics under natural light irradiation.

Heterogeneous Fenton-like system has been proved to be an promising alternative to Fenton system due to its easy separation. However, it’s a challenge to design heterogeneous Fenton-like catalysts with high activity and great durability. Here, ternary solid solution Fe1-xZnxS were prepared via hydrothermal synthesis as heterogeneous Fenton-like catalysts. The Fe0.7Zn0.3S sample exhibited state of the art activity for yielding OH by H2O2 decomposition, and the ultrafast degradation of phenol was achieved in 4 min at initial acidic condition under room temperature. The phenol degradation rate constant of Fe0.7Zn0.3S was 99 and 70 times of ZnS and FeS, respectively. Further, we show that the unique structural configuration of iron atoms, the formation of FeS2-pyrite with (200) plane, are responsible for the excellent activity. The intermediate products were identified by LC–MS and a possible pathway was accordingly proposed to elucidate the mechanism of phenol degradation by OH. Overall, this work provides an idea for the rational design of the relevant heterogeneous Fenton-like catalysts.

A three-dimensional (3D) reduced graphene oxide–Mn3O4 nanosheet (Mn3O4@rGO) hybrid was achieved by simple electrodeposition technique. Small palladium nanoparticle were homogeneously anchored onto Mn3O4@rGO substrate through the reduction of palladium salt. The interpenetrating network architecture of Mn3O4@rGO greatly inhibited the aggregation of 2D sheets of Mn3O4 and rGO, and the open 3D orientation of the Mn3O4@rGO hybrid nanosheets on the electrode facilitated both mass transport and electron transfer as well as maximally exposed active sites. The introduction of Mn3O4 enhanced the structural and electrochemical stability of rGO. The as-synthesized Pd/Mn3O4@rGO hybrid was employed as an electrocatalyst for electrocatalytic hydrogen evolution reaction (HER). The electrocatalyst showed a low overpotential of 20 mV at 10 mA cm−2, a small Tafel slope of 48.2 mV dec−1, and a large exchange current density of 0.59 mA cm−2. Importantly, the catalyst possessed superior durability with 85.87% of catalytic activity after a long-time test (10 h). This work presents a simple and efficient stratagy to construct high-performance electrocatalysts for energy and environmental applications.

The ultrathin thickness and lateral morphology of a two dimensional (2D) MoS2 nanosheet contribute to its high surface-to-volume ratio and short diffusion path, rendering it a brilliant electrode material for lithium-ion batteries (LIBs). However, the low conductivity and easy restacking character of the pure MoS2 nanosheet during extended cycling result in severe capacity fading and poor cycling performance. In this work, we developed an attractive strategy by using a metal-doping method to engineer chemical, physical and electronic properties of MoS2, achieving an outstanding performance in LIBs. The computational results show that V–Mo–S has semimetallic properties. Semimetallic vanadium molybdenum sulfide nanoarrays (V–Mo–S NAs) were prepared to overcome the low conductivity of semiconducting MoS2 and thus further optimize its performance in LIBs. A reversible capacity as high as 1047 mA h g−1 was achieved at 1000 mA g−1. It also displayed an excellent stability even after 700 cycles. This fascinating study may pave a way for utilizing semimetallic material-based nanomaterials for batteries.

Studies on the removal of As(III) by Fe-based materials have been carried out for decades, but the time-consuming process and low removal capacity are obstacles for large-scale practical applications. Here, a rapid and efficient technique was proposed for the removal of As(III) using Cu-doped Fe@Fe2O3 core–shell nanoparticles (CFF) synthesized by a facile two-step reduction method and aging process, which realized a thorough removal of As(III) from smelting wastewater at neutral pH within 30 min. The copper doped in CFF not only provided two extra oxygen reduction pathways to enhance the molecular oxygen activation, but also improved the electron transfer ability and removal efficiency of As(III). The existence of copper contributed to the rapid oxidization and adsorption of As(III), and the removal rate increased nearly 10-times in the aerobic system. Meanwhile, the proposed Cu-doped Fe@Fe2O3 core–shell nanoparticles and shifted oxygen reduction pathway could be easily scaled up for other transition metals, such as Ni. Molecular dynamics (MD) simulations based on the large-scale atomic/molecular massively parallel simulator (LAMMPS) were also employed to investigate the formation process of CFF. Furthermore, the removal efficiency of arsenic in smelting wastewater remained to be 90% after 6 times of cycling. Therefore, the distinctive oxidation activities of CFF hold great promise for applications in arsenic removal.

The molecular oxygen activation (MOA) process tends to be the rate-limiting step for photocatalytic selective organic transformation such as aromatic alcohol oxidation. Herein, using the plasmonic 0D/2D W18O49/ZnIn2S4 (WOZ) heterojunctions as a model system, we firstly shed light on the ultra-efficient MOA origin of the synergism of photothermal effect and continuous hot electrons injection through both experimental and DFT calculations. This synergistic action not only enhances the generation rate of •O2¯ and reduces the activation energy barrier, but also significantly increases the adsorption of the O2 and activates it more easily, thus achieving efficient photocatalytic selective oxidation of benzyl alcohol to benzaldehyde. Meanwhile, the charge separation and transfer processes involved in O2 activation can be further optimized with the Z-scheme transfer route. This work would provide an exciting opportunity to construct more active photothermal catalysts with ultra-high efficiency of MOA for a wide variety of organic transformations with solar energy.

This study investigated the technical applicability of a combination of Phanerochaete chrysosporium (P. chrysosporium) with photocatalyst graphitic carbon nitride (g-C3N4) for organic matters removal from landfill leachate under visible light irradiation. Photocatalyst g-C3N4 was well immobilized on the hyphae surface of P. chrysosporium by calcium alginate. The typical absorption edge in visible light region for g-C3N4 was at about 460 nm, and the optical absorption bandgap of g-C3N4 was estimated to be 2.70 eV, demonstrating the great photoresponsive ability of g-C3N4. An optimized g-C3N4 content of 0.10 g in immobilized P. chrysosporium and an optimized immobilized P. chrysosporium dosage of 1.0 g were suitable for organic matters removal. The removal efficiency of total organic carbon (TOC) reached 74.99% in 72 h with the initial TOC concentration of 100 mg L-1. In addition, the gas chromatography coupled with mass spectrometry (GC-MS) measurements showed that immobilized P. chrysosporium presented an outstanding removal performance for almost all organic compounds in landfill leachate, especially for the volatile fatty acids and long-chain hydrocarbons. The overall results indicate that the combination P. chrysosporium with photocatalyst g-C3N4 for organic matters removal from landfill leachate may provide a more comprehensive potential for the landfill leachate treatment.

It is attractive to photocatalytically purify wastewater and simultaneously convert solar energy into clean hydrogen energy. However, it is still a challenge owing to the relatively low photocatalytic efficiency of photocatalysts. In this study, we synthesized a molybdenum disulfide (MoS 2 ) quantum dot-decorated 3D nanoarchitecture (MoS 2 QDs) of indium zinc sulfide (ZnIn 2 S 4 ) and reduced grapheme oxide (MoS 2 QDs@ZnIn 2 S 4 @RGO) photocatalyst using a simple solvothermal method. The RGO promotes the electron transfer, and the highly dispersed MoS 2 QDs provides numerous catalytic sites. The photocatalytic purification of rhodamine B (RhB), eosin Y (EY), fulvic acid (FA), methylene blue (MB) and p -nitrophenol (PNP) in simulated wastewaters were further tested. The degradation efficiencies and TOC removal were 91% and 75% for PNP, 92.2% and 72% for FA, 98.5% and 80% for MB, 98.6% and 84% for EY, and 98.8% and 88% for RhB, respectively (C organics = 20 mg/L, C catalyst = 1.25 g/L, t = 12 h, I light = 3.36 × 10 −5 E L −1 s −1 ). Among these tests, the highest hydrogen production was achieved (45 μmol) during RhB degradation. Both experimental and calculational results prove that lower LUMO (lowest unoccupied molecular orbit) level of organic molecules was available for transferring electrons to catalysts, resulting in more efficient hydrogen production. Significantly, the removal efficiencies of natural organic substances in actual river water reached 76.3–98.4%, and COD reduced from 32 to 16 mg/L with 13.8 μmol H 2 production after 12 h.

Molybdenum disulfide (MoS 2 ) is a promising non-precious-metal cocatalyst to replace scarcity and cost Pt, but still suffers from less active sites and poor electrical transport due to the unoptimized geometrical configuration of MoS 2 on the semiconductor surface. Here, two different morphological and structural CdS/MoS 2 heterostructures were successfully prepared by a simple hydrothermal reaction with glucose-assisted or not. With the help of glucose, the MoS 2 nanosheets can nearly vertical stand on the CdS nanowires, which do not have the characteristic stacked layer structure of MoS 2 . This unique configuration leads to a high exposure of the active edge sites and increases charges separation and transfer rate. As expected, the 1D/2D nearly vertical CdS/MoS 2 heterostructures exhibited excellent photocatalytic activity and good durability even after being reused five times. Simultaneously, an apparent quantum yield can be reached to 60.3% at 420 nm, which was the advanced performance among all CdS/MoS 2 composites. This work will provide an intriguing and effective approach on design of low-cost and efficient photocatalysts for enhanced HER performance.

The development of efficient visible light photocatalysts for refractory organic pollutant degradation has gained considerable attention in wastewater treatment. Here, close-connected AgI/Bi 5 O 7 I (AI/BOI) heterojunctions were successfully synthesized by a facile deposition–precipitation approach. Multiple antibiotics, including tetracycline, deoxytetracycline, oxytetracycline, and ciprofloxacin, were employed as target pollutants to evaluate the visible light photoactivity of the prepared samples. The obtained AI/BOI-5 exhibited optimal photocatalytic activity and photoelectric property, which was 8.62 times (tetracycline degradation rate) and 12.44-fold (photocurrent intensity) than those of bare BOI, respectively. The strengthened visible light absorption and effective separation and transfer of the photoinduced electrons and holes should be responsible for the improvement of photocatalytic performance. The mineralization ability comparison was explored by total organic carbon and three-dimensional excitation–emission matrix fluorescence spectra measurements. The AI/BOI-5 also revealed good adaptability to higher initial contaminant concentrations and desired photodegradation stability in practical applications. By the studies of reactive species trapping, electron spin resonance and nitroblue tetrazolium agent of O 2 − transformation experiments verified that O 2 − , h + , and OH were all produced in AI/BOI photocatalytic systems, while only O 2 − and h + worked during BOI photolysis. A possible Z-scheme heterojunction mechanism can be ascribed to the enhanced photocatalytic degradation of multiple antibiotics induced by AI/BOI. This work gives deep insight into heterostructured photocatalysis and provides a novel way to construct and design highly efficient photocatalysts for water purification.

The serious photocorrosion of silver phosphate (Ag 3 PO 4 ) has limited its practical applications. In this work, we propose a strategy to suppress its photocorrosion by the construction of a Z-Scheme photocatalytic system, which composed of reduced graphene oxide-enwrapped Ag 3 PO 4 (Ag 3 PO 4 @RGO) and La,Cr-codoped SrTiO 3 (La,Cr:SrTiO 3 ). Dramatically, this system shows superior anti-photocorrosion and photocatalytic performances in degradation of both RhB and 2,4-DNP. Especially for RhB, it can be completely degraded after only 5 min under intense sunlight irradiation. The improved photoactivity and anti-photocorrosion of Ag 3 PO 4 @RGO@La,Cr:SrTiO 3 can be attributed to the following: (i) The sufficient interfacial contact between Ag 3 PO 4 and RGO is favorable to transfer the carriers and lengthen the lifetime of it; (ii) the package of Ag 3 PO 4 with RGO could work as a sheltering layer to protect Ag 3 PO 4 from photocorrosion. (iii) The aggregation of photogenerated holes in the VB of Ag 3 PO 4 makes it a rich-hole region due to Z-Scheme electrons transport mechanism, which can protect Ag 3 PO 4 from the photo-reduction. This strategy provides a new thought of protecting photosensitive semiconductor from photocorrosion and could regard as an efficient application method for environmental cleaning under natural sunlight irradiation. Furthermore, it even could be extended to outdoor or indoor air cleaning in the future.

In this paper, novel popcorn balls-like ZnFe 2 O 4 -ZrO 2 composite microspheres were successfully fabricated by a simple hydrothermal method. The morphology, structure and optical property of the microspheres were characterized. The microspheres were used as the photocatalysts to degrade 2,4-dinitrophenol, and exhibited superior photocatalytic performance. Under simulated solar visible light irradiation, the degradation rate of ZnFe 2 O 4 -ZrO 2 photocatalyst (mass ratio of ZnFe 2 O 4 /ZrO 2 = 2:1) was almost 7.4 and 2.4 times higher than those of pure ZnFe 2 O 4 and ZrO 2 . The enhancement could attribute to stronger light absorption, lower carrier recombination and multi-porous structure of the microspheres. Moreover, the popcorn balls-like photocatalysts can be easily separated, because of the magnetism of the samples. After five times runs, the photocatalyst still showed 90% of its photocatalytic degradation efficiency. This work demonstrated a good prospect for removing organic pollutants in water.

The metallic 1T-MoS2 has attracted considerable attention as an effective catalyst for hydrogen evolution reactions (HERs). However, the fundamental mechanism about the catalytic activity of 1T-MoS2 and the associated phase evolution remain elusive and controversial. Herein, we prepared the most stable 1T-MoS2 by hydrothermal exfoliation of MoS2 nanosheets vertically rooted into rigid one-dimensional TiO2 nanofibers. The 1T-MoS2 can keep highly stable over one year, presenting an ideal model system for investigating the HER catalytic activities as a function of the phase evolution. Both experimental studies and theoretical calculations suggest that 1T phase can be irreversibly transformed into a more active 1T′ phase as true active sites in photocatalytic HERs, resulting in a "catalytic site self-optimization". Hydrogen atom adsorption is the major driving force for this phase transition.

The scrupulous design of hierarchical structure and highly active crystal facets exposure is essential for the creation of photocatalytic system. However, it is still a big challenge for scrupulous design of TiO2 architectures. In this paper, bird’s nest-like anatase TiO2 microstructure with exposed highly active (001) surface has been successfully synthesized by a facile one-step solvothermal method. Methylene blue (MB) is chosen as a model pollutant to evaluate photocatalytic activity of as-obtained TiO2 samples. The results show that the photocatalytic activity of the bird’s nest-like sample is more excellent than P25 in the degradation of MB due to high specific surface area and highly active (001) crystal facets exposure when tested under simulated solar light. Besides, it can be readily separated from the photocatalytic system by sedimentation after photocatalytic reaction, which is a significant advantage against conventional powder photocatalyst. The bird’s nest-like microspheres with novel structure may have potential application in photocatalysis and other fields.

Molybdenum disulfide (MoS2) is a promising non-precious-metal catalyst, but its performance is limited by its density of active sites and poor electrical transport. Here, we report the design and preparation of cracked monolayer 1T MoS2 with a porous structure through the ultrasonication enhanced lithium intercalation of hydrothermally synthesized MoS2 nanosheets. The unique resulting catalyst can have more active sites introduced via the formation of porosity within the monolayer nanosheet, and the electrical transport ability can be increased through the change in electronic states from semiconducting in the 2H phase to metallic in the 1T phase. As is expected, the cracked monolayer 1T MoS2 exhibited good durability and an excellent hydrogen evolution reaction performance with a low overpotential (at 10 mA cm−2) of 156 mV (V vs. RHE) in acid media and a small Tafel slope of 42.7 mV dec−1. This work will provide an intriguing and effective approach to designing electrocatalysts based on MoS2 or other layered materials with enhanced HER performance.

Potassium‐ion batteries (KIBs) are one of the most appealing alternatives to lithium‐ion batteries, particularly attractive in large‐scale energy storage devices considering the more sufficient and lower cost supply of potassium resources in comparison with lithium. To achieve more competitive KIBs, it is necessary to search for anode materials with a high performance. Herein, the bimetallic oxide Sb2MoO6, with the presence of reduced graphene oxide, is reported as a high‐performance anode material for KIBs in this study, achieving discharge capacities as high as 402 mAh g−1 at 100 mA g−1 and 381 mAh g−1 at 200 mA g−1, and reserving a capacity of 247 mAh g−1 after 100 cycles at a current density of 500 mA g−1. Meanwhile, the potassiation/depotassiation mechanism of this material is probed in‐depth through the electrochemical characterization, operando X‐ray diffraction, transmission electron microscope, and density functional theory calculation, successfully unraveling the nature of the high‐performance anode and the functions of Sb and Mo in Sb2MoO6. More importantly, the phase development and bond breaking sequence of Sb2MoO6 are successfully identified, which is meaningful for the fundamental study of metal‐oxide based electrode materials for KIBs.

Molybdenum disulfide (MoS2) is considered as one of the most effective materials which can supersede the high cost and scarcity of metal platinum (Pt) for the hydrogen evolution reaction (HER). One road block lying in access to high catalytic performance of MoS2 emanates from the inert basal plane. To enable inert basal plane of flexible MoS2, we demonstrate an effective synthesis strategy via the progressive transformation of MoS2 to MoS2-xOx with O atomically dispersed under actual photo-catalytic hydrogen evolution condition. The rate of hydrogen production of new reconstructed MoS2-xOx nanosheets is improved to be much higher than that of the initial MoS2. Our theoretical calculation results indicate that the appropriate O substitution and strain could modulate the surface electronic state and optimize the Gibbs free energy (ΔGH) of MoS2, thus dramatically accelerating the catalytic efficiency. This work showcases a promising route to achieve tunable photochemical reconstruction by optimizing the electronic structure for low-cost and robust MoS2-based HER catalysts.

The optimized geometrical configuration of muitiple active materials into hierarchical nanoarchitecture is essential for the creation of photocatalytic degradation system that can mimic natural photosynthesis. A bamboo-like architecture, CuO nanosheets and Ag nanoparticles co-decorated TiO2 nanotube arrays (Ag/CuO/TiO2), was fabricated by using simple solution-immersion and electrodeposition process. Under simulated solar light irradiation, the 2,4-dinitrophenol (2,4-DNP) photocatalytic degradation rate over Ag/CuO/TiO2 was about 2.0, 1.5 and 1.2 times that over TiO2 nanotubes, CuO/TiO2 and Ag/TiO2, respectively. The enhanced photocatalytic activity of ternary Ag/CuO/TiO2 photocatalyst was ascribed to improved light absorption, reduced carrier recombination and more exposed active sites. Moreover, the excellent stability and reliability of the Ag/CuO/TiO2 photocatalyst demonstrated a promising application for organic pollutant removal from water.

A new hierarchical nanoarchitecture with integration of multiple active materials has been developed for highly efficient hydrogen evolution reaction (HER), by decorating a perpendicular hybrid of MoS2 and N-doped graphene nanosheets with CdS nanoparticles. The unique architecture promoted light trapping and absorption for highly efficient light harvesting and photocarrier generation, and offered an unblocked electron transport pathway for rapid charge separation/transport to suppress charge recombination. Its high surface area and high density of active sites result in highly efficient utilization of photogenerated carriers for productive HER. Significantly, without using noble metals as co-catalysts, the photocatalysts demonstrated rapid HER rates as high as 5.01 mmol h−1 g−1 under visible-light irradiation, which was approximately 25 times that of pure CdS. The hydrogen production remained stable after a continued test for 30 h, showing an exceedingly high performance and superior stability.

Three-dimensional (3D) network-like graphitic carbon nitride nanobelts (g-C3N4 NBs) were facilely achieved by the hydrothermal treatment of bulk g-C3N4 in a medium strong oxalic acid solution (1 M, pH 0.89). The positions of the conduction band (CB) and valence band (VB) were upraised from −0.90 and +1.86 eV for bulk g-C3N4 to −0.92 and +1.92 eV for g-C3N4 NB networks with enhanced redox ability, respectively. With an optimized Pt loading of 3%, the g-C3N4 NB networks showed excellent visible-light photocatalytic H2 production activity (1360 μmol g−1 h−1), which was 10.9 times higher than that of optimized 2% Pt@bulk g-C3N4 (124.7 μmol g−1 h−1) using triethanolamine as a sacrificial agent. Furthermore, Pt@g-C3N4 NBs exhibited a considerable rate of H2 evolution of 33.3 μmol g−1 h−1, much higher than 1.79 μmol g−1 h−1 for Pt@bulk g-C3N4 in distilled water without any sacrificial agents, revealing a great potential for photocatalytic overall water splitting. This outstanding performance not only originates from its unique 3D nanostructure and prolonged electron lifetime, but also from the electronic structure modulation and improved redox capacities of the CB and VB. The pH effect of hydrothermal conditions on the g-C3N4 molecular structure, chemical elements, optical properties and catalytic performance is also expounded. This study demonstrates a facile and environmentally friendly strategy to design highly efficient g-C3N4 catalysts for potential applications in solar energy driven photocatalytic water splitting.

The optimised geometrical configuration between TiO2 nanorods (NRs) arrays and reduced graphene oxide (RGO) is essential for their application in catalysis of photoelectrochemical hydrogen production system. The scrupulous design of hierarchical nanoarchitectures by integration of multiple active materials can reinforce the light harvesting efficiency, enhance photocarrier generation and provide fast electron transport and efficient charge collection. Graphene film formed on the top surface and at the bottom of titanium dioxide nanorod (TiO2 NRs) arrays were scrupulously fabricated in this paper. More importantly, the hydrogen production rate of RGO@TiO2NR@RGO hybrid nanostructures was up to 800 μmol/h−1m2 (radiation intensity: 160 mW/cm2) which is over 2.5 times compared with bare TiO2NR.