CuS Nanosheets Research Articles

Tailoring the geometry of visible and near-infrared light active CuSe nanostructure for enhanced photocatalytic activity

Semiconductor photocatalysts play a pivotal role in fostering a sustainable environment by harnessing solar energy directly into chemical energy to achieve various photocatalytic processes. Therefore, a visible-infrared active photocatalyst is the next level of demand for solving the alarming environmental issues. In this regard, the present article reports the investigations of crucial mechanisms and conditions leading to pure and defect-free hexagonal 2D CuSe nanosheets (NSs) and the influence of their structural architecture on visible-infrared active photocatalytic performance. Here, it was achieved by the conventional hydrothermal method by varying the pH of the reaction mixture. XRD analysis was used to examine the crystal structure and lattice parameters of CuSe NSs. The presence of H+ ions was suggested to significantly influence the observed anisotropic crystallite growth across different pH conditions. EDS and XPS analysis exhibited the purity and stoichiometry of 2D CuSe NSs, revealing that the obtained stoichiometry was consistent with CuSe composition. The morphological characteristics were investigated using FE-SEM as well as HR-TEM analyses, and the specific surface area was determined using Brunauer-Emmett-Teller analysis in which a significant change occurred in response to the variation in reaction conditions. The optical properties of optimized 2D CuSe NSs show excellent absorption in the visible and near-infrared region utilizing full solar with a notable decrease in emission intensity, suggesting a reduction in recombination rates due to pH-induced changes in the nanoarchitecture. Herein, methylene blue, a well-established model dye, was used as a probe to assess the photocatalytic activity of the synthesized CuSe NSs. Notably, the CuSe NSs synthesized under neutral conditions demonstrate a remarkable methylene blue degradation efficiency, reaching approximately 98 % within approximately 45 minutes, indicating a high degradation rate. Finally, an in-depth exploration into the intricacies of photocatalytic performance, degradation mechanisms, and the recyclability test was conducted, accompanied by a thorough investigation into the feasibility of CuSe NSs for their practical application in photocatalytic wastewater treatment.

Interfacial evaporation device based on melamine foam supported MOFs-derived CuS nanosheets for highly efficient water evaporation

Sunlight-driven interfacial evaporation has been considered an effective solution to address water scarcity and seawater desalination with minimal environmental impact. We designed a sunlight-driven interfacial evaporation device using the porous melamine foam (MF) as the carrier to stabilize the loading of metal−organic frameworks (MOFs) derived CuS nanosheets. The MOFs-derived CuS nanosheets (M-CuS) have a full-spectrum solar light absorption rate of 95 % and the porous channels existing inside M-CuS effectively improve the light capturing ability and contribute to the rapid thermal response of M-CuS. The M-CuS was loaded on the MF through the adhesion of polyvinyl alcohol (PVA) to obtain an integrated M-CuS/MF aerogel with a stable structure. PVA further improves the hydrophilicity of MF and ensures a continuous supply of water to M-CuS/MF during the evaporation process. The unique porous structure of M-CuS/MF further promotes the absorption of sunlight, and the low thermal conductivity of MF (0.036 Wm−1K−1) could reduce the radiative and convective heat loss from the material to the surrounding environment. The evaporation rate and photothermal conversion efficiency of CuS/MF are 1.46 kg m−2h−1 and 86 % under one sunlight, respectively. The continuous seawater evaporation cycle experiments (15 times) show that the device can maintain a stable evaporation rate. The excellent salt blocking performance of M-CuS/MF suggest the promising long-term stable desalination applications.

Enhanced photocatalytic aerobic oxidative desulfurization of diesel over FeMo6Ox nanoclusters decorated on CuS nanosheets

Photocatalytic aerobic oxidative desulfurization (PAODS) presents a promising and carbon-neutral avenue for desulfurizing petroleum products. However, existing photocatalysts encounter limitations in activating oxygen and show sluggish kinetics in sulfide-to-sulfone conversion, hampering widespread implementation. Herein, we present a FeMo6Ox nanocluster-modified CuS photocatalyst for PAODS reaction using air as an oxygen source. Through experimental characterization and density functional theory (DFT) calculations, we elucidate that the incorporation of FeMo6Ox nanoclusters can modulate the CuS electron density, which results in the generation of electron trap states and facilitates the separation of electron-hole pairs. We show that the variation of water content in air alters the generation efficiency of different reactive oxygen species (ROS), highlighting the potential to optimize moisture levels for achieving the highest catalytic efficiency. The optimized catalytic system exhibits a record specific activity of 10.42 mmol g−1 h−1, and more importantly, achieves deep desulfurization of authentic diesel, showcasing its appealing application prospects.

Constructing Cu9S5@CuSe heterostructures under microwave irradiation for rechargeable magnesium batteries

Copper chalcogenides are believed as the prospective cathode materials for rechargeable magnesium batteries. However, their practical application is seriously restricted by slow diffusion and reaction kinetics due to the large charge/radius ratio of divalent Mg2+ ions. Herein, a simple two-step microwave-assisted synthesis method is rationally developed to construct Cu9S5@CuSe heterostructures as the capable cathode materials for rechargeable magnesium batteries. Two-dimensional CuSe nanosheets are vertically grown on the surface of single-crystal Cu9S5 substrate through selenation reaction under microwave irradiation to form the mixed-dimensional heterostructures. Electrochemical measurements reveal that the as-synthesized Cu9S5@CuSe heterostructures show high reversible capacity of 240 mAh g−1 and good long-term cyclic stability with approximate 0.013 % capacity decay per cycle at 500 mA g−1 within 1000 cycles. Furthermore, the obviously enhanced rate capability can be achieved in comparison with that of single-crystal Cu9S5 substrate and CuSe nanoparticles. Ex-situ X-ray photoelectron spectroscopy and X-ray diffraction characterizations reveal favourable electrochemical conversion reaction over the Cu9S5@CuSe heterostructure cathode. The superior electrochemical properties are attributed to the optimized diffusion kinetics within the unique heterostructure. This research offers a valuable strategy to develop high-performance cathode materials with favourable kinetics for magnesium batteries.

In-situ growth of CuS on polyimide film to construct dense and continuous network: Achieving excellent electrothermal and EMI shielding performance

The performance of the electrothermal film is generally determined by conductive filler network. However, it is still challenging to construct a dense network of conductive fillers in the electrothermal film. In this work, we develop a simple and efficient method to construct a dense and continuous network via in-situ growth of CuS nanosheets on the surface of polyimide (PI) film with stable interfacial bonding. The obtained PI@CuS electrothermal film is further packaged by commercially available PTFE and PI tapes to achieve desirable surface hydrophobic self-cleaning function and stability for the use in different environments. By tuning the network density of CuS nanosheets, it imparts excellent electrothermal conversion efficiency and cycling stability to the PI@CuS film, whose surface temperature could rapidly ramp up over 200 °C at 8 V. The film also exhibits excellent photothermal performance, reaching close to 100 °C at 100 mW/cm2. The anti-icing/de-icing experiment shows that the icing time is prolonged significantly at low temperature and the melting time is reduced dramatically. Furthermore, the PI@CuS film also exhibits outstanding electromagnetic interference (EMI) shielding effectiveness of 57.1 dB with a thickness of only 80 μm, and excellent tensile strength of over 90 MPa. The in-situ growth strategy provides a novel route for the fabrication of the electrothermal film with excellent overall performance.

Nanoreactor Confined and Enriched Intermediates for Electroreduction of CO2 to C2+ Products.

In the process of electroreduction of carbon dioxide (eCO2RR) to multi-carbon (C2+) products, it is imperative to enhance the concentration of key intermediate species on the catalyst surface. The utilization of micro-nano reactors to achieve confinement effects has been widely observed in various catalytic reactions, yet it has seldom been employed in eCO2RR. Here, we present a novel nanoreactor composed of stacked CuS nanosheets for eCO2RR to C2+ products. In comparison to catalyst comprising of nanosheet with open space, the C-C coupling within this confined nanospace is significantly enhanced, resulting in the increase of Faraday efficiency (FE) of C2+ products to 53 %. In situ infrared (IR) spectroscopy reveals the confinement and enrichment of key intermediate by the nanoreactor. Our research findings demonstrate that a meticulously designed nanoreactor can elevate the selectivity of C2+ products, thereby aiding in the design of eCO2RR catalysts.

Stable Q-switched and femtosecond mode-locked erbium-doped fiber laser based on a CuSe nanosheets saturable absorber.

Stable Q-switched and femtosecond mode-locked erbium-doped fiber laser (EDFL) have been achieved using CuSe nanosheets as novel saturable absorber (SA), where the CuSe nanosheets were prepared by a hydrothermal method. The nonlinear optical properties of CuSe nanosheets were measured using an Z-scan setup, revealing nonlinear absorption coefficients of -3.67 ± 0.22 cm GW-1 at 1560 nm. The prepared CuSe nanosheets were mixed with polyvinyl alcohol (PVA) to obtain a CuSe-PVA SA with a modulation depth of 3.8 ± 0.13%, and it was utilized to realize a Q-switched EDFL, obtaining the narrowest pulse duration of 1.29 µs and the maximum output power of 5.96 mW, which corresponds to a pulse energy of up to 103.7 nJ. In addition, CuSe nanosheets were deposited on a D-shaped fiber (DSF) to fabricate a CuSe-DSF SA with a modulation depth of 5.6 ± 0.17%, and it was utilized to realize a mode-locked EDFL. The mode-locked EDFL demonstrated a low threshold of only 42 mW, a pulse duration of 740 fs, and a maximum output power of 9.7 mW. Meanwhile, it exhibited a high signal-to-noise ratio of 72 dB. To the best of our knowledge, this is the first time of CuSe nanosheets as SA in EDFL. The results demonstrate that CuSe nanosheets are a highly promising nonlinear optical material with great potential for applications in ultrafast photonics.

A Breathable Fibrous Membrane with Coaxially Heterogeneous Conductive Networks toward Personal Thermal Management and Electromagnetic Interference Shielding.

The expeditious growth of wearable electronic devices has boomed the development of versatile smart textiles for personal health-related applications. In practice, integrated high-performance systems still face challenges of compromised breathability, high cost, and complicated manufacturing processes. Herein, a breathable fibrous membrane with dual-driven heating and electromagnetic interference (EMI) shielding performance is developed through a facile process of electrospinning followed by targeted conformal deposition. The approach constructs a robust hierarchically coaxial heterostructure consisting of elastic polymers as supportive "core" and dual-conductive components of polypyrrole and copper sulfide (CuS) nanosheets as continuous "sheath" at the fiber level. The CuS nanosheets with metal-like electrical conductivity demonstrate the promising potential to substitute the expensive conductive nano-materials with a complex fabricating process. The as-prepared fibrous membrane exhibits high electrical conductivity (70.38 S cm-1), exceptional active heating effects, including solar heating (saturation temperature of 69.7 °C at 1 sun) and Joule heating (75.2 °C at 2.9V), and impressive EMI shielding performance (50.11dB in the X-band), coupled with favorable air permeability (161.4mm s-1 at 200Pa) and efficient water vapor transmittance (118.9g m-2 h). This work opens up a new avenue to fabricate versatile wearable devices for personal thermal management and health protection.

Exploring one-pot colloidal synthesis of klockmannite CuSe nanosheet electrode for symmetric solid-state supercapacitor device

In this study, we successfully synthesized klockmannite CuSe nanosheets, showing their promising potential for application in supercapacitors.

Preparation of porous CuS/modified-diatomite composite via a facile in situ loading process for efficient recovery of silver ion from aqueous solution

The study on the recovery of silver ion (Ag+) from silver-containing wastewater is of great significance to heavy metal pollution control and noble metal retrieval. In this work, a porous CuS/modified-diatomite composite was prepared via a pre-modification followed by a mild in situ coating process. A layer of CuS nanosheets was evenly coated onto pre-modified diatomite, and porosity of the diatomite support reserved. Aperture analysis results suggested that the composite possessed a broader porous distribution, higher specific surface area and pore volume than pure CuS. The neosynthetic composite exhibited outstanding adsorption performance for Ag+, according to the Langmuir adsorption isotherm model, with a maximum adsorption capacity of 822.7 mg/g for Ag+, approximately 84 times greater than that of raw diatomite (9.87 mg/g). The highest removal efficiency of the composite for Ag+ reached 99.9 %, and pH values (3–8) and coexisting ions (Na+, K+, Ca2+ and Mg2+) had little influence on the removal of Ag+. Kinetic studies and adsorption product analysis demonstrated that removal of Ag+ on the composite was occupied by chemisorption, arising from that the abundant porosity of diatomite support prompts Ag+ to diffuse onto the composite, and the uniformly coated CuS nanosheets provide abundant active sites for Ag+ chemisorption.

Plasmonic CuS 2D nanosheets through biologically and environmentally benign template free one-pot synthesis

Our research unveils a novel and eco-friendly technique for the synthesis of emerging two-dimensional Copper Sulfide (CuS) nanosheets through the sulfidation of surface-modified Cu NPs. These fabricated CuS nanosheets exhibit captivating properties such as fluorescence and surface plasmon resonance (SPR) within the near-infrared (NIR) spectrum, rendering them as remarkable candidates for transformative applications in bioimaging and medical sensing.The structural and optical characterization of the material were carried out, and the morphological characterization using SEM and HRTEM shows the formation of 2D CuS as exfoliated long sheets. The investigation projects a simple and cost-effective method to produce 2D Copper Sulfide (CuS) nanosheets. It is formed through a two-step process, including the synthesis of Cu NPs, and transformation of these colloidal Cu NPs into CuS nanosheets through sulfidation. It is found that the concentrations of sulfur and the surface modifying agents like curcumin and ascorbic acid influence nucleation and promote 2D growth of the nanosheets. The effect of sulfur concentration, pH, and surface modifying agents on SPR properties of the Cu NPs were investigated, and the results are presented here. Additionally, our findings indicate that both seed-mediated syntheses and ligand-assisted surface modification leads to the growth of these CuS nanosheets. The cellular studies show that sulfidation reduces the cellular cytotoxicity of Cu NPs. The sample also exhibits excellent stability and biocompatibility, and it is proved to be a promising candidate for photocatalytic, sensing, and biomedical applications, and hence emerges as a multifunctional 2D material.

In situ observation of the electrochemical behavior of Li–CO2/O2 batteries in an environmental transmission electron microscope

AbstractLi–CO2/O2 batteries, a promising energy storage technology, not only provide ultrahigh discharge capacity but also capture CO2 and turn it into renewable energy. Their electrochemical reaction pathways' ambiguity, however, creates a hurdle for their practical application. This study used copper selenide (CuSe) nanosheets as the air cathode medium in an environmental transmission electron microscope to in situ study Li–CO2/O2 (mix CO2 as well as O2 at a volume ratio of 1:1) and Li–O2 batteries as well as Li–CO2 batteries. Primary discharge reactions take place successively in the Li–CO2/O2–CuSe nanobattery: (I) 4Li+ + O2 + 4e− → 2Li2O; (II) Li2O + CO2 → Li2CO3. The charge reaction proceeded via (III) 2Li2CO3 → 4Li+ + 2CO2 + O2 + 4e−. However, Li–O2 and Li–CO2 nanobatteries showed poor cycling stability, suggesting the difficulty in the direct decomposition of the discharge product. The fluctuations of the Li–CO2/O2 battery's electrochemistry were also shown to depend heavily on O2. The CuSe‐based Li–CO2/O2 battery showed exceptional electrochemical performance. The Li–CO2/O2 battery offered a discharge capacity apex of 15,492 mAh g−1 and stable cycling 60 times at 100 mA g−1. Our research offers crucial insight into the electrochemical behavior of Li–CO2/O2, Li–O2, and Li–CO2 nanobatteries, which may help the creation of high‐performance Li–CO2/O2 batteries for energy storage applications.

Modulating the large vacancy types of CuS ultrathin nanosheets via defect engineering to improve the photocatalytic antibacterial performance

Defect engineering is emerging as an important tool for tuning the photocatalytic antibacterial properties of nanomaterials. However, its development is constrained by the lack of exploration of defect engineering for large defect types. We designed CuS and CuS-200 ultrathin nanosheets with different large vacancy types VCuSSCuCu and VCuSSCuCuCu, respectively. The antibacterial test results demonstrated that CuS-200 ultrathin nanosheets exhibited stronger bactericidal effect on Escherichia coli (E. coli) than CuS under near-infrared (NIR) light. The high antibacterial efficiency was attributed to the improved energy band structure, which helped CuS-200 absorb light and improved photothermal conversion efficiency. In addition, the optimized electronic structure and the strong oxygen adsorption ability drove CuS-200 to produce a large amount of reactive oxygen species (ROS). This work provided new ideas for the preparation of efficient bactericides and new strategies for the design and preparation of catalysts with specific photocatalytic properties.

Establishment of a photoactive heterojunction of triazine covalent-organic polymer and copper (II) selenide: Photoelectrochemical aptasensing strategy for efficiently detecting Salmonella typhimurium

The sensitive determination of foodborne pathogens in foodstuffs or water system is essential for protecting food and environment safety. Herein, we have proposed a photoelectrochemical (PEC) aptasensor based on two-dimensional (2D)/3D organic–inorganic heterojunction for the efficient detection of Salmonella typhimurium (S. typhimurium). The heterojunction was established via the in situ growth of copper (II) selenide (CuSe) nanosheets around the photoactive triazine covalent-organic polymer (COP) nanospheres, which was synthesized using 2,4,6-Tris(4-aminophenyl)-1,3,5-Triazine (TAPT) and 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde (Tp) as building blocks (denoted as TAPT-Tp-COP@CuSe). Integrating the features of TAPT-Tp-COP (such as large specific surface and pore size, multi-functionality, and rich defects) and CuSe (such as high photoabsorption ability, fast electron transfer and effective separation of the photo-generated charge carrier) not only can accelerate the photoelectric transformation efficiency, but also can promote the aptamer immobilization. Consequently, the constructed PEC aptasensor based on TAPT-Tp-COP@CuSe illustrated a low detection limit of 3.4 CFU mL−1 with a linear range from 1 × 101 to 1 × 105 CFU mL−1 toward S. typhimurium. In addition, it demonstrated high selectivity in light of the specific recognition of aptamer toward S. typhimurium, good reproducibility and stability, and promising regeneration ability, as well as wide applications for the detection of S. typhimurium in diverse foodstuffs systems. The present work provides a new aptasensing strategy for the effective detection of foodborne pathogens from diverse foodstuffs by combining the merits of COPs and PEC technique.

In-situ imaging electrocatalysis in a solid-state Li-O2 battery with CuSe nanosheets as air cathode

The development of highly efficient catalysts in the cathodes of rechargeable Li-O2 batteries is a considerable challenge. To enhance the electrochemical performance of the Li-O2 battery, it is essential to choose a suitable catalyst material. Copper selenide (CuSe) is considered as a more promising cathode catalyst material for Li-O2 battery due to its better conductivity and rich electrochemical active sites. However, its electrochemical reaction and fundamental catalytic mechanism remain unclear till now. Herein, in-situ environmental transmission electron microscopy technique was used to study the catalysis mechanism of the CuSe nanosheets in Li-O2 batteries during discharge and charge processes. It is found that Li2O was formed and decomposed around the ultrafine-grained Cu during the discharge and charge processes, respectively, demonstrating excellent cycling. This indicate that the freshly formed ultrafine-grained Cu in the conversion reaction catalyzed the latter four-electron-transfer oxygen reduction reaction, leading to the formation of Li2O. Our study provides important understanding of the electrochemistry of the Li-O2 nanobatteries, which will aid the development of high-performance Li-O2 batteries for energy storage applications.

Substantially boosting the performance of non-enzymatic glucose sensing: Introducing a novel CuS nanosheet anchored on hollow Ni(OH)2 nanosphere

Excess levels of glucose in the blood can result in various complications such as heart disease, kidney failure, and blindness. Therefore, it is crucial to quantitatively measure blood glucose levels. At room temperature, by employing coordinating etching and precipitating process, and sulfidation reaction, we have developed a range of glucose sensing materials, including hollow Ni(OH)2@CuS (H-Ni(OH)2@CuS), Cu2O cubes, hollow CuS (H-CuS), hollow Ni(OH)2 (H-Ni(OH)2), and core–shell Cu2O@Ni(OH)2. Electrochemical tests showed that H-Ni(OH)2@CuS has the highest glucose sensing sensitivity (2738.57 μA mM−1 cm−2) and the widest linear range (0.01–6.64 mM), with a detection limit of 3.3 μM (LOD = 3σ/S) compared with those of other materials. The superior electrochemical performance of H-Ni(OH)2@CuS can be attributed to the unique advantages of the hollow structure and the synergistic effect among multi-components in the heterojunction. The H-Ni(OH)2@CuS based sensor also demonstrates reliable reproducibility, long-term stability, and excellent anti-interference capability. Furthermore, it shows acceptable accuracy in detecting actual human serum samples, indicating its important practical application value.

Photothermally boosted Fenton-like activity of copper sulfide toward the catalytic degradation of 4-chlorophenol

Fenton/Fenton-like reactions have promising implications in biomedicine and environment-related remediation. However, their applications are still limited because of incomplete light utilization, low energy-conversion efficiency, and inefficient H2O2 utilization. Herein, near infrared (NIR) light absorbance and photothermal conversion were utilized for H2O2 activation to achieve 4-chlorophenol (4-CP) elimination from water by using a typical doped copper sulfide (Cu2−xS) semiconductor developed via a hydrothermal method. The obtained CuS is not only an attractive Fenton-like agent but also exhibits efficient photothermal conversion performance in the NIR spectral range, which broadens the use of the solar spectrum and is beneficial to the photothermal-enhanced Fenton-like degradation process. As expected, by irradiating with an NIR laser (1064 nm), the CuS exhibits excellent NIR absorption capacity and produces hyperpyrexia above 50 ℃. Importantly, the photothermal effects of the CuS nanosheets significantly enhanced the yield of the Fenton-like reaction by accelerating the generation and diffusion of free radicals (h+, •O2-, 1O2, and especially •OH), which enabled the key mechanism for pollutant degradation. In addition, CuS nanosheets exhibited good stability during the degradation of 4-CP, with low metal-ion leakage and a broad pH range applicability, and the degradation rate was hardly affected by laser power, catalyst concentration, and the presence of metal ions. These results demonstrate the strong potential of the photothermal-enhanced Fenton-like effect in pollutant degradation and propose a promising strategy for environmental remediation with the effective utilization of solar energy.

Combining functionalized CNT film with CuS microflowers through hyperbranched polymers for a flexible and appliable rechargeable Mg battery

The flexibility and high tolerance for mechanical deformation of batteries under operation is a critical aspect of flexible energy storage devices. In this paper, a large-area CNT film (CF) is prepared via chemical vapor deposition (CVD) method and then functionalized with hyperbranched polymers (HP) using the thiol-ene click reaction. CuS microflowers are in-situ grown on the flexible CNTs, where HP significantly enhances interfacial compatibility and greatly enhances the combination of CuS nanosheets with CNTs substrate. The modification strategy effectively promotes Mg2+ conversion reaction of CuS and greatly enhances the stability of the flexible electrode. The as-prepared flexible CuS/CF-HP cathode delivers a high magnesium storage capacity of 178 mAh g−1 at 50 mA g−1 and a good rate performance of 94 mAh g−1 at 2 A g−1, with a high Mg2+ diffusion coefficient of about ∼10−12 cm2 s−1 and a capacity retention rate of 79.2% after 200 cycles at 200 mA g−1. Furthermore, a practical flexible thin-film rechargeable Mg battery device based on the CuS/CF-HP cathode and Mg powder/CF anode was fabricated in a sealed polydimethylsiloxane package. The flexible full battery provides an outstanding power output as well as remarkable mechanical durability, demonstrating its potential applications for flexible energy storage devices.

The Facile Synthesis of Hollow CuS Microspheres Assembled from Nanosheets for Li-Ion Storage and Photocatalytic Applications.

Herein, well-defined hollow CuS microspheres assembled from nanosheets were successfully synthesized through a facile solvothermal method. Hollow CuS microspheres have an average diameter of 1.5 μm; moreover, the primary CuS nanosheets have an ultrathin thickness of about 10 nm and are bound by {0001} polar facets. When used as anodes for lithium-ion batteries (LIBs), hollow CuS microspheres exhibit excellent electrochemical properties, including a large discharge capacity (610.1 mAh g-1 at 0.5 C), an excellent rate capability (207.6 and 143.4 mAh g-1 at 1 and 5 C), and a superior cyclic stability (196.3 mAh g-1 at 1 C after 500 cycles). When used as photocatalysts for Rhodamine B (RhB), hollow CuS microspheres can degrade more than 99% of the initial RhB within 21 min. These excellent Li-ion storage properties and photocatalytical performances are attributed to their unique hierarchical hollow structure.

Short stick-shaped MnS/Mn0·5Cd0·5S grown in situ on CuSe nanosheets for efficient photocatalytic hydrogen evolution

The development of efficient and stable photocatalysts is very important for photocatalytic hydrogen evolution. In this work, a series of CuSe/MnS/Mn0·5Cd0·5S composites with high hydrogen evolution performance were synthesized by a simple hydrothermal method. The synthesized products were characterized by X-ray diffraction, Scanning electron microscopy, Transmission electron microscopy, Mapping, X-ray photoelectron spectroscopy, UV–Vis diffuse reflection spectroscopy, Mott–Schottky, Transient photocurrent response, Electrochemical impedance spectroscopy, and Photoluminescence spectroscopy. The obtained products showed efficient photocatalytic hydrogen evolution efficiency in Na2S–Na2SO3 solution under 300 W Xe lamp (λ ＞ 420 nm), with the highest photocatalytic hydrogen evolution efficiency reaching 24.7 mmol g−1 h−1, which was 4.1 times higher than pure MnS/Mn0·5C0·5S (5.99 mmol h−1 g−1) and 6.3 times higher than pure CdS (3.59 mmol h−1 g−1). A possible mechanism of photocatalytic hydrogen production was proposed. The addition of CuSe effectively enhances the photogenerated electron-hole separation efficiency and reduces the electron-hole pair complexation rate of CuSe/MnS/Mn0·5C0·5S composites. This work provides an effective way to improve the photocatalytic activity of Mn0·5Cd0·5S using transition metal selenide cocatalysts.