In-situ constructing cobalt incorporated nitrogen-doped carbon/CdS heterojunction with efficient interfacial charge transfer for photocatalytic hydrogen evolution

Designing an efficient heterojunction interface is an effective way to promote the electrons' transfer and improve the photocatalytic H₂ evolution performance. In this work, a novel hollow hybrid system of Co@NC/CdS has been fabricated and constructed. CdS nanospheres are anchored on the hollow-structured cobalt incorporated nitrogen-doped carbon (Co@NC) through a one-pot in-situ chemical deposition approach, forming an intimate interface and establishing an excellent channel to improve the electrons transfer and charge carriers separation between CdS and Co@NC cocatalyst, which immensely promotes the photocatalytic activity. The rate of photocatalytic H₂ evolution over hollow structured Co@NC/CdS heterojunction can be achieved 8.2 mmol g^?1 h^?1, which is about 45 times of pristine CdS nanospheres. The photocatalytic H₂ evolution mechanism has been investigated by the techniques of photoluminescence (PL) spectra, photocurrent-time (i-t) curves, electrochemical impedance spectroscopy (EIS) etc. This work aims to provide a new way in developing of high-performance advanced 3D heterojunction for photocatalytic hydrogen evolution.     

Fabrication of 1D/2D CdS/CoSx direct Z-scheme photocatalyst with enhanced photocatalytic hydrogen evolution performance

In this work, we fabricate a 1D/2D heterojunction photocatalyst composed of n-type CdS nanorods and p-type CoS_x nanoflake. This photocatalyst achieves a hydrogen evolution rate of 9.47 mmol g^?1 h^?1, which is 13.7 times higher than that of pure CdS nanorods. Scanning Kelvin Probe, Mott-Schottky plots, UV–Vis absorption spectra and surface photocarrier orienting reaction results indicate that the enhanced photocatalytic performance of CdS/CoS_x is owing to the fabrication of direct Z-Scheme heterojunction system which greatly improves the utilization, migration and separation rate of photo-generated carriers. To the best of our knowledge, this work is the first time to describe a CdS/CoS_x direct Z-scheme system with 1D/2D nanostructure, which can expedite the transfer process of photogenerated carriers with strong redox energy to participate in photocatalytic reactions.     

Noble metal free efficient photocatalytic hydrogen generation by TaON/CdS semiconductor nanocomposites under natural sunlight

Tantalum oxynitride have narrow band gap and its band potentials are suitable for visible light induced hydrogen generation. However, due to fast electron-hole recombination, the efficiency of photocatalytic hydrogen evolution reaction is very low. Herein, we have synthesized semiconductor heterojunction photocatalyst, i.e., TaON/CdS with suitable band positions by a simple precipitation method. Ratio between two semiconductors is optimized to obtain maximum hydrogen evolution. XRD, XPS and TEM analysis demonstrate the formation of heterojunction between these semiconductors. Among the synthesized catalysts, 3% TaON/CdS heterostructure exhibits the highest hydrogen evolution activity with H₂ production rate of 7.5 mmol h⁻¹ under natural solar light, whereas the rate is 11 mmol h⁻¹ under the visible light generated by xenon (Xe) lamp without the addition of any noble metal as the co-catalyst. The CdS and 3% TaON/CdS nanomaterials show an AQE of 5.1% and 12.2%, respectively. Combination of Mott-Schottky, UPS and DR UV–visible spectroscopy studies revealed the formation of S scheme semiconductor heterojunction between these nanomaterials with valence, conduction band positions, i.e., 1.46, −0.78 eV for CdS and 2.19, −0.66 eV for TaON, respectively. These band positions help in efficient e-h pair separation to produce hydrogen from water.     

Well-designed NiS/CdS nanoparticles heterojunction for efficient visible-light photocatalytic H2 evolution

Heterojunction photocatalysts based on semiconducting nanoparticles show excellent performance in many photocatalytic reactions. In this study, 0D/0D heterojunction photocatalysts containing CdS and NiS nanoparticles (NPs) were successfully synthesized by a chemical precipitation method. The NiS NPs were grown in situ on CdS NPs, ensuring intimate contact between the semiconductors and improving the separation efficiency of hole-electron pairs. The obtained NiS/CdS composite delivered a photocatalytic H₂ evolution rate (7.49 mmol h^?1 g^?1), which was 39.42 times as high as that of pure CdS (0.19 mmol h^?1 g^?1). This study demonstrates the advantages of 0D/0D heterojunction photocatalysts for visible light-driven photocatalytic hydrogen production.     

Construction of Au/g-C3N4/ZnIn2S4 plasma photocatalyst heterojunction composite with 3D hierarchical microarchitecture for visible-light-driven hydrogen production

In this paper, a novel Au/g-C₃N₄/ZnIn₂S₄ plasma photocatalyst heterojunction composite with 3D hierarchical microarchitecture has been successfully constructed by integrating Au/g-C₃N₄ plasmonic photocatalyst composite with 3D ZnIn₂S₄ nanosheet through a simple hydrothermal process. The Au nanoparticles were firstly anchored on the surface of pristine g-C₃N₄ material to get Au/g-C₃N₄ plasmonic photocatalyst. Ascribing to the surface plasmon resonance of Au nanoparticles, the obtained Au/g-C₃N₄ plasmonic photocatalyst shows a significant improved photocatalytic activity toward hydrogen production from water with visible light response comparing with pristine g-C₃N₄. Further combining Au/g-C₃N₄ plasmonic photocatalyst with 3D ZnIn₂S₄ nanosheet to construct a heterojunction composite. Owing to the synergistic effect of the surface plasmon resonance of Au nanoparticles in Au/g-C₃N₄ and the heterojunction structure in the interface of Au/g-C₃N₄ and ZnIn₂S₄, the prepared Au/g-C₃N₄/ZnIn₂S₄ plasma photocatalyst heterojunction composite shows an excellent photocatalytic activity toward hydrogen production from water with visible light response, which is around 7.0 and 6.3 times higher than that of the pristine C₃N₄ and Znln₂S₄ nanosheet, respectively. The present work might provide some insights for exploring other efficient heterojunction photocatalysts with excellent properties.     

Visible-light-driven HSr2Nb3O10/CdS heterojunctions for high hydrogen evolution activity

In this study, layered perovskite HSr₂Nb₃O₁₀ ultrathin nanosheets (HSNO-ns) was successfully exfoliated within 2 h by a facile microwave-assisted method. Then, HSNO-ns/CdS heterojunction was fabricated through a facile hydrothermal route for deposition of CdS nanoparticles on HSNO-ns. The photocatalytic performances of composites were systematically investigated and discussed by varying the CdS content. The results illustrated that the photocatalytic hydrogen production rate of HSNO-ns were significantly increased by coupled CdS nanoparticles on the HSNO-ns. The optimized HSNO-ns/CdS3 composites without noble metal showed highest photocatalytic activity, which was about 8.38 times and 330 times higher than that of pristine CdS and HSNO-ns, respectively, under the visible light irradiation (≥420 nm) using triethanolamine as sacrificial agent. The enhanced photocatalytic H₂ production activity was predominantly attributed to the strong optical absorption capacity, high specific surface area and improved charge carrier separation efficiency. Our present work provides a new pathway into the design of two-dimension nanosheets-based photocatalysts and promotes their practical application in various environmental and energy issues.     

3D hierarchical network NiCo2S4 nanoflakes grown on Ni foam as efficient bifunctional electrocatalysts for both hydrogen and oxygen evolution reaction in alkaline solution

The development of cost-effective and high-efficiency electrocatalysts for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) still remains highly challenging. Exposing as many active sites as possible is the key method to improve activity of HER and OER performance. In this communication, we demonstrate a novel 3D hierarchical network NiCo₂S₄ nanoflake grown on Ni foam (NiCo₂S₄-NF) as a highly efficient and stable electrochemical catalyst. The NiCo₂S₄-NF exhibits overpotentials as low as 289 and 409 mV at 100 mA cm^?2, superior long-term durability during a 20 h measurement, and a low Tafel slope of 89 and 91 mV dec^?1 for HER and OER in 1.0 M NaOH solution. The outstanding performance is owe to the inherent activity of ultrathin NiCo₂S₄ nanoflakes and the special structure of NiCo₂S₄-NF that can provide a huge number of exposed active sites, accelerate the transfer of electrons, and facilitate the diffusion of electrolyte simultaneously.     

Facile preparation of Pt/CdS photocatalyst by a modified photoreduction method with efficient hydrogen production

A series of 0.75 wt% Pt/CdS photocatalysts were successfully synthesized via a modified photoreduction process, with the assistance of a protective agent (polyvinylpyrrolidone, PVP) and/or structural inducer (NaI, NaBr, and NaCl). The physicochemical properties of the obtained 0.75 wt% Pt/CdS photocatalysts were characterized in more detailed. Their photocatalytic efficiencies were evaluated by visible-light photocatalytic hydrogen production. The results show that the photocatalytic activities of 0.75 wt% Pt/CdS photocatalysts for H₂ production mainly depend on the type of structural inducer. Furthermore, a suitable ratio of PVP/NaI is necessary to optimize the photocatalytic performance of Pt/CdS composites. Notably, 0.75 wt% Pt/CdS (PVP/NaI = 4:1) gains the highest hydrogen production activity with a rate of 1155.8 μmol h^?1, which is 1.8 times higher than that of 0.75 wt% Pt/CdS obtained from the traditional photoreduction method (640.9 μmol h^?1) and 17.3 times higher than that of the bare CdS sample (66.9 μmol h^?1). The as-prepared 0.75 wt% Pt/CdS photocatalyst (PVP/NaI = 4:1) also exhibits a good stability. An optimum ratio of PVP/NaI not only causes a decrease in particle size of Pt nanoparticles but also leads to an increase in BET specific surface area of Pt/CdS and an enhanced electron transfer capability of Pt nanoparticles, which should be responsible for the enhanced photocatalytic performance.     

Highly efficient hydrogen evolution catalysis based on MoS2/CdS/TiO2 porous composites

Efficient production of hydrogen through visible-light-driven water splitting mechanism using semiconductor-based composites has been identified as a promising strategy for converting light into clean H₂ fuel. However, researchers are facing lots of challenges such as light absorption and electron-hole pair recombination and so on. Here, new sheet-shaped MoS₂ and pyramid-shaped CdS in-situ co-grown on porous TiO₂ photocatalysts (MoS₂CdSTiO₂) are successfully obtained via mild sulfuration of MoO₃ and CdO coexisted inside porous TiO₂ monolith by a hydrothermal route. The scanning electron microscopy and transmission electron microscopy results exhibit that the MoS₂CdSTiO₂ composites have average pore size about 500 nm. The 3%MoS₂10%CdSTiO₂ demonstrated excellent photocatalytic activity and high stability for a hydrogen production with a high H₂-generation rate of 4146 μmol h^?1 g^?1 under visible light irradiation even without noble-metal co-catalysts. The super photocatalytic performance of the visible-light-driven hydrogen evolution is predominantly attributed to the synergistic effect. The conduction band of MoS₂ facilitates in transporting excited electrons from visible-light on CdS to the porous TiO₂ for catalytic hydrogen production, and holes to MoS₂ for inhibiting the photocorrosion of CdS, respectively, leading to enhancing the efficient separation of electrons and holes.     

In-situ construction of Mo3S4/Cd0.5Zn0.5S heterojunction: An efficient and stable photocatalyst for H2 evolution

In this work, Mo₃S₄/Cd_0.5Zn_0.5S heterojunction with abundant porosity was in-situ synthesized by one-step hydrothermal method. Characterization results clearly indicate that the composite material are composed of nanoparticles with an average particle diameter about 65 nm and abundant inter-particle pores are present in between. The XPS analysis found that when Mo₃S₄ was introduced, the XPS peak positions of Cd²⁺ and Zn²⁺ were shifted from the XPS peak positions of Cd²⁺ and Zn²⁺ in pristine Cd_0.5Zn_0.5S, which indicates that there is an interaction between Mo₃S₄ and Cd_0.5Zn_0.5S at the interface. Subsequently, the Mo₃S₄/Cd_0.5Zn_0.5S (72.1 mmol h⁻¹ g⁻¹) heterojunction can achieve much higher photocatalytic hydrogen production rate than the pristine Cd_0.5Zn_0.5S (7.54 mmol h⁻¹ g⁻¹), and even higher than Cd_0.5Zn_0.5S (56.44 mmol h⁻¹ g⁻¹) loaded with the noble metal Pt (2.0%), indicating that heterojunction can effectively enhance photocatalytic activity. In addition, the improvement in photocatalytic activity of Mo₃S₄/Cd_0.5Zn_0.5S is highly related with enhanced absorption and utilization of light due to the presence of the inter-particle pores which inhibit recombination of electron-hole pairs, promote charge separation and accelerate the migration of photogenerated carriers.     

0D/3D ZnIn2S4/Ag6Si2O7 nanocomposite with direct Z-scheme heterojunction for efficient photocatalytic H2 evolution under visible light

Constructing heterojunction structure is a feasible way to realize an efficient and durable photocatalysts. Herein, a novel Z-scheme zero/three dimensional (0D/3D) ZnIn₂S₄/Ag₆Si₂O₇ (ZIS/ASO) composite was rationally designed, synthesized and analyzed. ZIS/ASO composite possesses a layer structure for increasing light response, a special 0D/3D structure for reducing the photo-induce carriers migration path, and numerous active sites for absorbing H₂O and producing H₂. This composite retains the high oxidation and reduction ability by facilitating separation and migration as well as limiting recombination of photo-induced carriers via the intimate interface between ZIS and ASO. Undoubtedly, the synthesized ZIS/ASO photocatalyst achieved a high photocatalytic H₂ activity, and the optimum sample shows a satisfactory H₂ evolution rate of 590.56 μmol g⁻¹ h⁻¹, distinctly better than that of pure ZIS. More importantly, this composite exhibits high stability and recyclability and is expected to be applied in practical application. Based on the H₂ evolution experimental results and electrochemical tests, the Z-scheme heterostructure construction of the composite was confirmed. This work expects to inspire a unique protocol for synthesizing Z-scheme photocatalysts for water splitting under visible light irradiation.     

Z-scheme CdS/WO3 on a carbon cloth enabling effective hydrogen evolution

Photocatalytic water splitting for hydrogen (H₂) generation is a potential strategy to solve the problem of energy crisis and environmental deterioration. However, powder-like photocatalysts are difficult to recycle, and the agglomeration of particles would affect the photocatalytic activity. Herein, a direct Z-scheme CdS/WO₃ composite photocatalyst was fabricated based on carbon cloth through a two-step process. With the support of carbon cloth, photocatalysts tend to grow uniformly for further applications. The experimental results showed that the H₂ yield of adding one piece of CdS/WO₃ composite material was 17.28 μmol/h, which was 5.5 times as compared to that of pure CdS-loaded carbon cloth material. A cycle experiment was conducted to verify the stability of the as-prepared material and the result demonstrated that the H₂ generation performance of CdS/WO₃ decreased slightly after 3 cycles. This work provides new ideas for the development of recyclable photocatalysts and has a positive significance for practical applications.     

Interfacing CdS particles on Ni foam as a three-dimensional monolithic photocatalyst for efficient visible-light-driven H2 evolution

Solar photocatalytic water splitting using particulate semiconductors has been valued as a potentially scalable way for the production of clean H₂ energy, yet the performances of the powder-suspension systems are constrained by insufficient utilization of light energy and tedious recycling of photocatalyst particles. Here, we present a high-performance photocatalytic H₂ evolution using a visible-light-driven CdS-based monolithic photocatalyst with three-dimensional (3D) heterostructure. The monolithic photocatalyst is fabricated by firmly growing CdS microspheres on a Ni(OH)₂ nanosheet-modified Ni foam (NF) (denoted as CdS-NiS_x/NF) via a simple hydrothermal process. The structure and component synergy endows the monolithic CdS-NiS_x/NF photocatalyst advantageous features including high-density CdS microspheres for visible light harvesting, multiple heterojunction interfaces for efficient electron-hole separation, and abundant interfacial NiS_x active sites for efficient H₂ evolution reaction (HER). Upon visible light irradiation, the monolithic CdS-NiS_x/NF photocatalyst exhibits an outstanding photocatalytic H₂ evolution activity with an enhanced rate of 6.2 mmol·h⁻¹ g⁻¹_CdS, which is 6 times higher than that of the suspended CdS powder. In addition, the structural integrity of the CdS-NiS_x/NF enables a good stability for H₂ evolution over a 30 h reaction. This monolithic photocatalyst is scalable in preparation and compatible for device fabrication, which offers great potentials for applications in solar cells, photoelectrocatalysis, and electrocatalysis.     

Surface polar charge induced Ni loaded CdS heterostructure nanorod for efficient photo-catalytic hydrogen evolution

Designing of artificial heterostructure photo-catalysts to crop solar energy for H₂ evolution from water is of great importance nowadays. The ultrafine Ni (0.5, 1.0, 2.0 and 5.0 wt%) particles loaded CdS nanorods were synthesized by a simple chemical process. XRD shows the crystalline phase of CdS with increase in size from 17 to 28 nm with 10.19% and 10.06% enhancement in the lattice strain and the dislocation density for Ni (0.5–5.0 wt%). The XPS peaks observed at 854.88 eV and 861.07 eV for Ni²⁺ with energy separation of 6.18 eV confirmed the existence of NiO on Ni surface. The Raman bands for pure CdS and Ni (1.0 wt%)-CdS nanorods were observed at 300 cm^?1 and 293 cm^?1 for 1LO phonon and 601 cm^?1 and 586 cm^?1 for 2LO phonon, respectively. The Ni loading tuned the CdS band gap from 2.36 to 2.20 eV. The eight fold enhancement in the CdS specific surface area i.e., from 4.19194 m² g^?1 to 34.8343 m² g^?1 was achieved. After Ni loading, the synergetic effect of efficient electron separation and transportation was observed by the continuous quenching of luminescence emission intensity and the reduction of charge transfer resistance from 706 Ω for CdS to 484 Ω of CdS. The Ni (1.0 wt%)@ NiO optimal loading on CdS results highest photo-catalytic H₂ evolution of 9.0 mmol at rate of 1.8 mmol h^?1, which is about 50 times higher than that of 180 μmol at rate of 36 μmol h^?1 for pure CdS. A thin layer of NiO on plasmonic Ni surface could be the promising system for photo-catalytic H₂ evolution due to visible light photo-activity.     

ZnCdS/NiAl hydrotalcite S-scheme heterojunction for efficient photocatalytic hydrogen evolution

ZnCdS/NiAl hydrotalcite S-scheme heterojunction with highly effective photocatalytic hydrogen evolution activity was devised and prepared by a simple solution-based mixing way. Layered double hydroxide (LDH), also called hydrotalcite-like compound, is composed of adjustable metal cations and exchangeable anions between layers. The hydrogen evolution performance of ZnCdS/NiAl LDH is about 7 times that of ZnCdS and 130 times that of NiAl LDH. Because the rod-shaped ZnCdS and the layered NiAl LDH can construct close interface contact. This interface contact helps to accelerate charge transfer, thereby achieving more effective photocatalytic hydrogen evolution. The S-scheme ZnCdS/NiAl LDH heterojunction catalyst shows excellent hydrogen evolution and good stability, which not only gets benefits from the prominent performances of the cob-like ZnCdS and the layered NiAl LDH but also the matching bandgap structure for them. The configuration of the S-scheme ZnCdS/NiAl LDH heterojunction catalyst accelerates the rapid charge movement and inhibits the recombination of charge carriers, thereby greatly enhancing visible-light-driven water splitting, which is corroborated by the PL spectrum, I-T, LSV, EIS, MottSchottky and UV–vis DRS studies, etc.     

Efficient interfacial charge transfer of 2D/2D CoP/CdS heterojunction for extremely boosted photocatalytic H2 evolution performance

Constructing 2D/2D heterojunction photocatalysts has attracted great attentions due to their inherent advantages such as larger interfacial contact areas, short transfer distance of charges and abundant reaction active sites. Herein, 2D/2D CoP/CdS heterojunctions were successfully fabricated and employed in photocatalytic H₂ evolution using lactic acid as sacrificial reagents. The multiple characteristic techniques were adopted to investigate the crystalline phases, morphologies, optical properties and textual structures of heterojunctions. It was found that integrating 2D CoP nanosheets as cocatalysts with 2D CdS nanosheets by Co–S chemical bonds would significantly boost the photocatalytic H₂ evolution performances, and the 7 wt% 2D/2D CoP/CdS heterojunction possessed the maximal H₂ evolution rate of 92.54 mmol g^?1 h^?1, approximately 31 times higher than that of bare 2D CdS nanosheets. Photoelectrochemical, steady photoluminescence (PL) and time-resolved photoluminescence (TRPL) measurements indicated that there existed an effective charge separation and migration over 2D/2D CoP/CdS heterojunction, which then markedly lengthened the photoinduced electrons average lifetimes, retarded the recombination of charge carriers, and caused the dramatically boosted photocatalytic H₂ evolution activity. Moreover, the density functional theory (DFT) calculation further corroborated that the efficient charge transfer occurred at the interfaces of CoP/CdS heterojunction. This present research puts forward a promising strategy to engineer the 2D/2D heterojunction photocatalysts endowed with an appealing photocatalytic H₂ evolution performance.     

Efficient photocatalytic hydrogen evolution on amorphous MoSx-modified CdS/KTaO3 heterojunctions under visible light irradiation

Constructing heterostructures with efficient charge separation is a promising route to improve photocatalytic hydrogen production. In this paper, MoS_x/CdS/KTaO₃ ternary heterojunction photocatalysts were successfully prepared by a two-step method (hydrothermal method and photo deposition method), which improved the photocatalytic hydrogen evolution activity. The results show that the rate of hydrogen evolution for the optimized photocatalyst is 2.697 mmol g^?1·h^?1under visible light, which is 17 times and 2.6 times of the original CdS (0.159 mmol g^?1 h^?1) and the optimal CdS/KTaO₃(1.033 mmol g^?1 h^?1), respectively, and the ternary photocatalyst also shows good stability. The improvement on photocatalytic hydrogen evolution performance can be attributed to the formation of heterojunction between the prepared composite materials, which effectively promotes the separation and migration of photo-generated carriers. Amorphous MoS_x acts as an electron trap to capture photogenerated electrons, providing active sites for proton reduction. This provides beneficial enlightenment for hydrogen production by efficiently utilizing sunlight to decompose water.     

Novel triptycene-based microporous polymers decorated with Cd0.5Zn0.5S quantum dots to form 0D/3D heterojunction for efficient photocatalytic hydrogen evolution

A novel and porous triptycene-based microporous polymer (TMP) was synthesized through a palladium acetate-catalyzed Suzuki reaction, and then Cd_0.5Zn_0.5S quantum dots (CZS QDs) were homogeneously decorated onto the TMP by a facile in situ precipitation approach to fabricate a 0D/3D heterojunction for the first time. Characterizations indicate TMP with large specific surface area (809 m² g⁻¹) not only stabilizes CZS QDs but also provides abundant photocatalytic active sites, which can facilitate the activation and adsorption of H₂O molecules. The CZS QDs@TMP heterojunction possesses remarkably improved photocatalytic hydrogen evolution activity and outstanding photostability. The optimized CZS QDs@TMP-1 heterojunction exhibits highest hydrogen-producing rate of 81.33 mmol h⁻¹ g⁻¹, about 16.1 times higher than that of pristine CZS. The high photocatalytic activity of CZS QDs@TMP is due to several positive factors, such as high surface area, construction of n-n type heterostructures, tiny size effect of CZS QDs and close contact between 0D CZS QDs and 3D TMP, which will synergistically promote the visible-light response, boost the interfacial charge transfer and reduce the photocorrosion of CZS.     

Constructing 3D hierarchical Zn0.2Cd0.8S microspheres for the improved visible-light-driven photocatalytic performance

Nanorod assembled three-dimensional (3D) hierarchical Zn_0.2Cd_0.8S microspheres were successfully prepared by a facile one-pot microwave hydrothermal approach using ethylenediamine (EN) as a template agent. The optimal 3D hierarchical Zn_0.2Cd_0.8S microspheres (ZCS-30) is obtained when adding 30 mL into the synthetic system, which can function as a highly active photocatalyst for H₂ evolution under visible-light irradiation with the wavelength of 420 nm, delivering an activity approximately 2.5 and 7.5 times higher than that of Zn_0.2Cd_0.8S nanoparticles and CdS counterparts, respectively, and giving an apparent quantum efficiency (AQE) of 7.4%. Furthermore, the ZCS-30 photocatalyst shows the good stability after the catalytic H₂ evolution for 15 h (5 cycles). In addition, the ZCS-30 photocatalyst exhibits the excellent degradation of Rhodamine B (Rh B) almost up to 80% under the visible light irradiation over a period of 150 min. The results demonstrate that ZCS-30 can serve as a promising visible-light-driven bifunctional photocatalyst for water splitting and dye degradation.     

Usage of natural leaf as a bio-template to inorganic leaf: Leaf structure black TiO2/CdS heterostructure for efficient photocatalytic hydrogen evolution

Herein, first time we report that highly efficient sheet like leaf structure black TiO₂ (LBT)/CdS hetero-structure (LBT/CdS). Photocatalytic hydrogen generation was tested for different material in the presence of visible light (λ ≥ 420 nm) irradiation. 10 wt% of LBT loaded CdS (10LBT/CdS) exhibit maximum photocatalytic H₂ generation rate about ~10 mmol h^?1 g^?1, which is higher than the H₂ production results of pristine CdS (6 mmol h^?1 g^?1) and leaf black-TiO₂ 5.1 mmol h^?1 g^?1) respectively. Detailed characterization revealed that higher photocatalytic activity was mainly attributed to enormous spatial transfer efficiency of photo-excited charge carriers at the hetero-junction between LBT and CdS in LBT/CdS. Additionally, introduction of 2D black leaf-TiO₂ to CdS act as a mat and enhances the mobility of charge carriers. In addition, presence of anatase-rutile surface-phase junction in leaf TiO₂ (synthesized at 750 °C) and more edges, steps and corners on the CdS synergistically increased the photocatalytic H₂ generation and photocurrent response of LBT/CdS.