Efficient Utilization Of Solar Energy Research Articles

Plasmonic MoO2 coupled with sulfur-incorporated NiMoO4 as multifunctional heterostructures for solar thermoelectric self-powered urea electrolysis

Efficient conversion and utilization of abundant renewable solar energy is highly desirable for the sustainable production of green hydrogen, but it is still a great challenge. In the present study, the multifunctional heterostructure of MoO2 coupled with sulfur-incorporated NiMoO4 (S-NiMo) on nickel foam (NF) was explored to construct a self-powered hydrogen production system that ingeniously integrates a solar thermoelectric generator (STEG) and a urea electrolyzer. The plasmonic MoO2 in S-NiMo/NF acts as a solar absorption unit to covert solar energy into thermal energy, which can combine with thermoelectric (TE) module for efficient power generation. When served as an electrocatalyst, the S-NiMo/NF exhibits excellent electrocatalytic performances to promote hydrogen evolution reaction (HER), urea oxidation reaction (UOR) and overall urea electrolysis. Under simulated solar irradiation at light intensity of 5 sun, the S-NiMo/NF-based STEG-urea electrolyzer system can produce 2.68 μmol of hydrogen per minute via the four-series connected S-NiMo/NF-STEGs. This self-powered thermoelectric urea electrolysis system offers new opportunities to convert renewable solar energy into green hydrogen.

Modeling of Photovoltaic Power Generation Systems Considering High- and Low-Voltage Fault Ride-Through

The photovoltaic power station has a good development prospect because it can realize concentrated and efficient utilization of solar energy. Considering the detail model of the photovoltaic power station has a power electronic device with a high-frequency switching characteristic, it is not suitable for electromagnetic transient analysis of a large photovoltaic power plant. To solve this problem, this study proposes a simplified model, average model, which uses a controlled current source to replace the power electronic converter and analyzes application backgrounds, advantages, and disadvantages of two models. Then, the control circuit of the average model is improved to switch the control mode by itself when the high- and low-voltage fault occur in the system to make sure the high- and low-voltage ride-through can be completed successfully. Finally, the correctness and effectiveness of the improved average model are verified by simulation.

An improvement approach for the solar collector by optimizing the interface of assembling structure

The heat pipe evacuated tube solar collectors were widely used in building heating. The defects in the assembling process caused by the roughness of solid materials have a severe effect on the thermodynamic performance of the solar collector. To enhance the efficiency of the solar collectors, an improvement approach by filling the gaps in the interface between assembling structures using thermal interface materials is proposed. The interface between heat pipe and fin is a major contributor to the heat resistance in collector tubes, thus affecting the utilization efficiency of solar energy. Three thermal greases were selected, and then the interface after filling the gaps was characterized and analyzed. To verify the effectiveness of the new improvement approach, two experimental setups including a solar collector and a solar heating system were built. Experimental results show that the average collection efficiency of the solar collector increases by 4.8% compared with that of the unprocessed one. Moreover, the optimization of the interface enhances the sensitivity and response speed of the collector on solar irradiance, and shortens the startup time by 27.2% of the solar heating system. The work provides a promising way to upgrade the solar collector with heat pipe evacuated tube.

Elevating the Photothermal Conversion Efficiency of Phase-Change Materials Simultaneously toward Solar Energy Storage, Self-Healing, and Recyclability.

To alleviate the predicament of resource shortage and environmental pollution, efficiently using abundant solar energy is a great challenge. Herein, we prepared unique photothermal conversion phase-change materials, namely, CNT@PCMs, by introducing carbon nanotubes (CNTs) used as photothermal conversion materials into the recyclable matrix of phase-change materials (PCMs). These devised CNT@PCMs cleverly combine the photothermal conversion capability of CNTs and the thermal energy storage capability of traditional PCMs. Especially, the surface temperature of the prepared CNT@PCMs can be raised to 100 °C within 165 s under the solar simulator (150 mW cm-2), showing a surprising heating rate that is much higher than that of the reported works and achieving a higher photothermal conversion efficiency for solar energy in this work. Furthermore, these CNT@PCMs can hold high melting latent heat with a maximum value at 110.0 J g-1, exhibiting remarkable thermal storage ability aside from preeminent photothermal conversion capability. Intriguingly, the introduction of dynamic oxime group-carbamate bonds into the molecular structure can endow CNT@PCMs with an outstanding self-healing performance and recyclability. The broken CNT@PCMs sample can be healed in 2 min under IR-laser irradiation. Importantly, the phase-change and mechanical properties and photothermal conversion efficiency of CNT@PCMs can also remain virtually unchanged after multiple recycles. It is of great significance to design this style of CNT@PCMs for achieving the efficient utilization of solar energy and environmental protection.

Magnetically accelerated thermal energy storage within Fe3O4‐anchored MXene‐based phase change materials

AbstractInherent weak photon‐capturing ability is a long‐standing bottleneck for pristine phase change materials (PCMs) in photothermal conversion application. To conquer this difficulty, herein, magnetic Fe3O4 nanoparticles were in situ anchored between the layers and the surface of two‐dimensional MXene for the infiltration of myristic acid (MA) by an in situ chemical anchoring strategy. Benefiting from the synergistic localized surface plasmon resonance effect of MXene and Fe3O4 nanoparticles, our designed MXene@Fe3O4‐MA composite PCMs harvested an ultrahigh photothermal conversion efficiency of 97.7%. During the photothermal conversion process, MXene can capture photons and convert solar energy into heat energy efficiently, and the in situ anchored Fe3O4 nanoparticles further enhanced the photothermal conversion efficiency. Moreover, the introduction of Fe3O4 nanoparticles improved the thermal energy storage density (144.17 J/g) of MXene‐MA composite PCMs since Fe3O4 nanoparticles provided more heterogeneous nucleation sites for MA. Simultaneously, MXene@Fe3O4‐MA composite PCMs were endowed with excellent paramagnetism, and realized efficient magnetic‐thermal conversion. Additionally, MXene@Fe3O4‐MA composite PCMs exhibited excellent energy conversion stability, thermal stability, and reliability after undergoing multiple thermal cycles. Therefore, high‐performance MXene@Fe3O4‐based energy conversion composite PCMs are promising candidates to accelerate efficient utilization of the practical solar energy and magnetic energy

In-situ deposition preparation of n-octadecane@Silica@Polydopamine-doped polypyrrole microcapsules for photothermal conversion and thermal energy storage of full-spectrum solar radiation

Phase change materials （PCMs） play an essential role in utilizing solar energy. However, there exist inherent defects of pure PCMs, such as low solar energy utilization efficiency and easy leakage. In this work, we successfully prepared a novel type of n-octadecane@Silica@Polydopamine-doped polypyrrole photothermal phase change microcapsules (SCN@PAP micro-PCMs), contained n-octadecane (n-OD) as the core material, silica as the intermediate layer, and polydopamine and polypyrrole composite (PDA-PPY) as the wall material. The microcapsules' morphology, chemical structure, photothermal and thermal storage properties, and thermal stability were investigated. This study confirmed that polydopamine (PDA) doping positively regulates the optical properties of polypyrrole (PPY). The PDA-PPY(PAP) was uniformly deposited on the surface of n-OD@SiO2 phase change microcapsules (SCN micro-PCMs) in granular form with the appropriate doping ratio. Further, tuning the ratio of SCN micro-PCMs to PAP and pyrrole (PY) to dopamine (DA) could endow SCN micro-PCMs with good photothermal properties and retain high thermal storage properties. When the mass ratio of PY: DA = 1:0.032 and SCN: PAP = 6:1, the prepared SCN@PAP micro-PCMs exhibited high photothermal conversion efficiency up to 97.31%, with a melting enthalpy of 145.3 J/g. The enthalpy value decreased by less than 1 J/g after 100 heating and cooling cycles demonstrating excellent thermal energy storage cycling stability. The SCN@PAP micro-PCMs are expected to be promising in promoting the efficient utilization of solar radiation.

Experimental research on the performance of BIPV/T system with water-cooled wall

Solar photovoltaic/thermal building integrated power/heat technology (BIPV/T) can provide both electricity and heat to buildings, which is important for improving the efficiency of solar energy utilization and reducing building energy consumption. In this paper, a BIPV/T system with water-cooled wall is proposed. The water-cooled wall heat exchanger is not in direct contact with the PV module, and uses air to dissipate heat from the PV module, which in turn heats domestic water, and can provide hot water or hot air to the building as needed. This paper experimentally investigates the system’s ability to produce domestic hot water and power generation performance, with an average power generation efficiency of 12.6% for the whole day and providing 35 °C domestic hot water for more than 7 h. The results of this paper have some guiding significance for the efficient operation of BIPV/T.

A novel spectral-splitting solar indoor lighting system with reflective direct-absorption cavity: Optical and thermal performance investigating

Sunlight contains a wide range of the spectrum, and the spectrum used for plant photosynthesis is mainly located in the visible band (380–780 nm), while the spectral energy of other bands is not suitable for plant growth because it generates heat in summer. In this paper, a novel spectral-splitting solar indoor lighting system with a reflective direct-absorption cavity for Plant Factory was developed, which used the combination of pure water and spectrum splitting mirrors to perfectly separate the visible light and non-visible light of sunlight. Visible light was conducted to Plant Factory by optical fiber to provide illumination for plants, and non-visible light was trapped and then absorbed by a reflective direct-absorption cavity and convert into thermal energy. The structural parameters of the reflective direct-absorption cavity were optimized based on the Monte Carlo method, and the light conduction and heat transfer models were established to analyze the photo-thermal performance of the device. The results of indoor and outdoor tests showed that the solar energy utilization efficiency of the device could reach 50%, among which the light transmission efficiency and heat collection efficiency were 24.7% and 25.3%, respectively. The temperature of the optical fiber coupling end face was kept in the range of 27–37 °C, which can ensure the safe and efficient operation of the optical fiber. It provides a new idea for the protection of optical fiber, the efficiency improvement of sunlight conduction lighting technologies, and the energy saving of the Plant Factory lighting in the future.

Boosting Total Conversion Efficiency of Hybrid Photovoltaic–Thermal via a Spectral Splitter/Absorber Based on Lossy Periodic Structured Media

A spectral splitter plays a crucial role in the hybrid photovoltaic (PV)–thermal design for efficient solar energy harvesting. Herein, the lossy medium periodic structure of ITO/Si is utilized to construct a novel spectral splitter/absorber that selectively reflects the solar energy in PV band while absorbing the rest of solar energy. The as‐prepared spectral splitter/absorber demonstrates a weighted reflectance of 75.6% in the PV band, an absorptance of 83.1% in the photothermal (PT) band, as well as superior angular performance across a broad incident range of 0°–60°. The proposed hybrid photovoltaic–thermal (PVT) system assembled with the spectral splitter/absorber with 1100 nm long edge of the PV band enhances the total electrical efficiency to 26.5%, higher than that of the individual Si PV cell (19.1%), resulting from the precise modulation of solar spectrum via the splitter/absorber to realize efficient utilization of solar energy in different bands. The temperature of PV cells in a hybrid PVT system also declines by ≈25 °C compared with the single‐Si PV cell. The PV band can be easily shifted to match other narrow‐bandgap PV cells due to intrinsic properties of near‐zero k of both ITO and Si at near‐infrared wavelength range and the large difference in n between them.

Powering Up an IoT-Enabled Smart Home

Smart cities and smart homes have a larger number of devices requiring continuous electricity. An inverter circuit is often used to cope up with power failures. Such inverters can also be used in the period of high demand for power to reduce the load on the grid. On the other hand, utilizing renewable energy is an important aspect of sustainable development. A solar-powered inverter reduces the usage of grid power and makes efficient utilization of solar energy. Further, the inverter can be integrated with microcontrollers to work on predetermined time slots to substitute the grid power. This paper describes the design of a novel solar-powered smart inverter that automatically switches the power supply from the grid to the inverter during peak hours. It is designed to suit smart home requirements up to 1 kW and a holistic design is presented. The performance of the circuit is analyzed and compared with similar works in literature to show the improvements. Simulations and hardware implementations show that the proposed system ensures an uninterrupted power supply for smart homes.

Extraordinary Promotion of Visible-Light Hydrogen Evolution for Graphitic Carbon Nitride by Introduction of Accumulated Electron Sites (BN2)

The application of accumulated electron sites on the catalyst surface for photocatalytic hydrogen production represents a prospective strategy for efficient utilization of solar energy. Herein, the accumulated electron sites (BN2) loaded on graphitic carbon nitride (G-CN) were prepared without effort by a two-step calcination method in which melamine was calcined and then heat-treated with NaBH4. When compared with that of the bulk G-CN, the rate toward water splitting to produce H2 of the represented catalyst (CN-B0.05) greatly increased by 2.3 times under illumination (λ ≥ 420 nm). The improved activity could be attributed to the decrease in interlayer distance and the potential barrier of interlayers which was beneficial to readily transfer electrons in the Z direction, improve the adsorption and activation of water, and decline the Gibbs free energies for H* adsorption. The increase in π–π conjugation facilitated enhancement of the separation efficiency of photogenerated electron–hole pairs and light-capturing capabilities in the visible region with the introduction of BN2 sites. An approach for efficient H2 production is demonstrated in this work.

Enhancement of solar absorption performance using TiN@SiCw plasmonic nanofluids for effective photo-thermal conversion: Numerical and experimental investigation

The heat exchange medium moderately determines the heat utilization efficiency of solar energy. Nanofluids, a type of working fluids with high thermal conductivity and strong light absorption, have been studied and applied to improve solar energy utilization. In this study, TiN@SiCw binary composite nanoparticles were prepared by a coupling agent method. The optical coupling absorption properties of TiN and SiCw nanoparticles were numerically simulated by the finite-difference time-domain method. Results showed the TiN@SiCw nanostructure can improve the width and intensity of spectral absorption. Then TiN@SiCw and SiCw nanofluids based on ethylene glycol were prepared by a two-step method and studied experimentally in terms of thermal conductivity and optical absorption. The photothermal conversion efficiency of the nanofluids was measured by a special flow and photothermal coupling model (side radiation). Experiments showed the thermal conductivity and light absorption of TiN@SiCw composite nanofluids were stronger than those of SiCw single-component nanofluids and the base fluid. Specifically, the energy absorption fraction and the photo-thermal efficiency of TiN@SiCw nanofluids at the highest concentration of 140 ppm were 96.2% and 90.5%, respectively, which were 12.1% and 21.7% higher respectively compared with SiCw nanofluids. Hence, the TiN@SiCw nanofluids are suitable for enhancing the efficiency of solar collectors.

Metallic zirconium carbide mediated near-infrared driven photocatalysis and photothermal sterilization for multidirectional water purification

Undoubtedly, taking full advantage of near-infrared light (NIR) for the photocatalytic reaction is a promising way to realize the efficient utilization of solar energy. In this work, zirconium carbide (ZrC) has been exploited as a NIR-driven photoactive substance for the simultaneous photodegradation of organic pollutants and photothermal sterilization of Escherichia coli (E. coli). The metallic nature and NIR-responsive localized surface plasmon resonance (LSPR) behaviors of ZrC are revealed by both experimental evidence and density function theory (DFT) calculations. ZrC exhibits extremely wide spectral absorbance, excellent NIR-triggered photosensitive effect and photothermal conversion efficiency. Activation kinetics was performed with DFT to investigate the activation process of O2 to •O2–. In addition, a possible NIR-mediated photocatalytic mechanism of ZrC was proposed on the basis of above DFT simulation and radical scavenging experiments. Metallic ZrC with NIR-responsive activity provides a new perspective for designing full-spectrum-driven photocatalysts.

Achieving extensive lossless coupling of photovoltaic and thermoelectric devices through parallel connection

Photovoltaic-thermoelectric hybrid systems have received broad attention in recent years owing to the capability of achieving efficient utilization of full-spectrum solar energy. This paper investigates the lossless coupling method of photovoltaic and thermoelectric devices to address the issue of large electrical coupling losses. The properties of the photovoltaic-thermoelectric hybrid systems with three connection modes, which are electrically separated, series, and parallel, are experimentally compared under different incident power densities. The electrical-thermal interaction characteristics of the photovoltaic cell and the thermoelectric device under different connection modes are further investigated with the theoretical method. The mechanism of achieving extensive lossless coupling of photovoltaic and thermoelectric devices under parallel connection is illustrated. The results demonstrate that when the incident power density is less than 15Wcm−2, the photovoltaic and thermoelectric devices can be losslessly coupled by the parallel connection. Both electrically separated and parallel coupling systems achieve the output power of 0.85 W, while the series coupling system power is only 0.41 W under the same incident power density of 15Wcm−2. Compared with the series mode, the parallel lossless coupling method can be achieved over a broader range of operating conditions and is more stable because of the small variation of the photovoltaic maximum power voltage under the practical varying irradiation and the effect of the weakened Peltier effect.

Bi2WO6‐based Z-scheme photocatalysts: Principles, mechanisms and photocatalytic applications

The development of novel photocatalysts for efficient utilization of solar energy is highly essential for the most critical humanitarian challenges, i.e., energy and water crises as well as environmental pollution. Bismuth tungstate (Bi2WO6), an outstanding Aurivillius phase perovskite, has attracted intensive attention as a visible-light-responsive photocatalyst because of its non-toxicity, low cost, and outstanding physicochemical characteristics, i.e., nonlinear dielectric susceptibility, ferroelectric piezoelectricity, pyroelectricity, catalytic behavior, modifiable morphology, strong oxidation power, and good photochemical stability. However, the photocatalytic activity of bare Bi2WO6 is restricted because of the inherent drawbacks such as poor light-harvesting efficiency, weak reduction potential, relatively low specific surface area, the fast recombination rate of photoinduced charge carriers, and thus poor quantum yields of photocatalytic reactions. Moreover, the impossibility of simultaneous strong redox ability (demanding wide bandgap) and high light-harvesting efficiency (requiring narrow bandgap) is considered as a big challenge for the practical application of Bi2WO6. Undeniably, the construction of Z-scheme photocatalytic systems is recommended strategy to overcome the above-mentioned disadvantages because of the efficient spatial separation of photogenerated charge carriers and the boosting the redox performance. This review summarizes the principles and recent developments on Z-scheme photocatalytic systems with special emphasis on the Bi2WO6-based photocatalysts, including the types, photocatalytic mechanisms and practical applications. Moreover, major differences between type-II heterojunction and Z-scheme photocatalyst have also been discussed. Additionally, the significant role of unique structures (e.g., core-shell and 2D/2D) for the improvement of photocatalytic activity of Z-scheme photocatalyst has been presented. Indeed, Bi2WO6-based Z-scheme photocatalysts have exhibited superior photocatalytic activity for various applications. For example, they show high photocatalytic activity towards water/wastewater treatment (removal of organic and inorganic pollutants, as well as microorganisms), air purification (decomposition of volatile organic compounds and inorganic matters), “green” energy conversion (e.g., generation of H2 and CH4 fuels under solar irradiation), and organic synthesis. It is thought that this remarkable activity of Bi2WO6-based Z-scheme photocatalysts might be attributed to the efficient solar light harvesting, separation and further transfer of charge carriers and strong redox ability. To the best of our knowledge, the present paper is the first attempt to summarize the Bi2WO6-based Z-scheme photocatalytic reactions, providing important insights and up-to-date information for the scientific community to fully explore the potential of Bi2WO6-based photocatalysts for renewable environmental remediation, energy conversion, and chemical synthesis.

Polyimide/phosphorene hybrid aerogel-based composite phase change materials for high-efficient solar energy capture and photothermal conversion

• We developed a new type of composite PCM for high-efficient solar energy capture. • The composite PCM was based on polyimide/phosphorene hybrid aerogel and PEG . • The introduction of phosphorene enhances solar photothermal absorption and conversion. • The composite PCM presents high solar light-to-heat conversion efficiency. • The composite PCM exhibits great potential for efficient utilization of solar energy. Solar energy is the cleanest and most abundant renewable energy source that can be utilized to displace fossil fuels and provide an effective solution for future energy shortage and climate change. Aiming at enhancing the capture efficiency of solar photothermal energy, we developed a novel type of phase-change composites based on polyimide (PI)/phosphorene (PR) hybrid aerogel and polyethylene glycol (PEG). The composites were prepared by fabricating a series of PI/PR hybrid aerogels with different loadings of PR nanosheets using freeze-drying and thermal imidization techniques, followed by vacuum impregnation of PEG as a phase change material into the aerogel framework. The obtained hybrid aerogels exhibited a lightweight nature with a density of 21.9 mg·cm −3 when 16 wt% PR nanosheets were incorporated, resulting in an extremely high PEG loading of 4067% in the aerogel system. The combination of PI and PR nanosheets leads to a significant enhancement in solar light absorption and photothermal energy conversion for the hybrid aerogel/PEG composites. The loading amount of PEG was also improved remarkably due to an increase in the volume capacity of the hybrid aerogels resulting from the introduction of PR nanosheets. The resultant hybrid aerogel/PEG composites not only exhibit a high latent-heat capacity of over 170 J·g −1 and a high photothermal conversion efficiency of 82.5%, but also show good thermal impact resistance to keep their original shape and form well after heating at 80 °C for 20 min and maintain a high thermal cycle stability after thermally cycled for 500 times. These superior performances make the hybrid aerogel/PEG composites capable of dealing with a wide range of applications in solar photothermal energy capture and storage. This study provides a promising strategy for the design and development of high-performance and lightweight composite PCMs to meet the requirement of applications for efficient utilization of solar energy.

Multi-doping strategy modified calcium-based materials for improving the performance of direct solar-driven calcium looping thermochemical energy storage

Calcium-looping thermochemical energy storage is a promising candidate in concentrated solar power plants. Solar-driven calcium-looping process via directly capturing sunlight can solve the challenges faced by traditional calcium-looping system, such as excessively high wall temperature, large thermal resistance, and low utilization efficiency of solar energy. In this work, we aim to improve optical absorption and cyclic stability of the direct solar-driven calcium-looping process with modified calcium-based materials for thermochemical energy storage. A simple sol-gel method was used to synthesize calcium-based composites via multi-doping strategy and the doping elements mainly included cerium (Ce), cobalt (Co), and manganese (Mn). Firstly, the role of calcium-based materials using single-doping element on the performance of thermochemical energy storage was revealed. The doping of Ce alone could generate oxygen vacancies and increase the adsorbed ability of CO2, accelerating the carbonization kinetics of CaO. The doping of Co alone played an important role in enhancing optical absorption while the doping of Mn alone was beneficial to cycling stability via providing a strong framework to inhibit sintering effect. Calcium-based materials using multi-doping strategy retained the function of single-doping effect on the performance of calcium-looping thermochemical energy storage, synergistically improving optical absorption, carbonization kinetics, and cyclic stability. Compared to pure CaCO3, Ce/Co/Mn co-doped Ca-based materials (CaCO3/5Ce–3Co–6Mn) exhibited a higher light trapping ability with optical absorption reached to 83.26% and more excellent cycling stability with effective conversion rate remained above 64% after 20 cycles. Furthermore, an interesting phenomenon that phase transformation of doped metal oxides formed by multi-doping strategy occurred during the calcination/carbonation cycling process was discovered and the underlying mechanisms were clarified. Finally, the feasibility of experiment by directly capturing concentrated sunlight to drive CaCO3 decomposition for storing solar energy was verified.

Synergistic effect of reduced graphene oxide and carbon black as hybrid light absorber for efficient and antifouling texture-based solar steam generator

Efficient utilization of solar energy as the cleanest and most plentiful natural resource for drinking water is a water is as sustianble and environmental friendly approach to obviate long-standing water scarcity. Carbon-based photothermal absorbers due to broadband light absorption are very interesting in interfacial solar steam generation systems. Herein, we investigate the convenient application of reduced graphene oxide (rGO) nanosheets with carbon black (CB) nanoparticles on the cotton fabric as a flexible texture-based photothermal absorber. Polyurethane (PU) as a self-floating insulator foam was selected to manage the energy loss and preserve light converted to heat on the fabric surface. The pristine cotton fabric around the foam provides continuous water supply through the capillary forces via cellulose fibers. Our reported system exhibits maximum evaporation rates and solar-thermal conversion efficiencies of 2.05, 2.09 kg.m-2h−1 and ∼ 98, 96 % for fresh and saline water, respectively. It was observed that the synergistic effect of rGO and CB caused to a reduction in the required GO concentration as a cost effective aspect. Proper washability of the treated fabrics without any visible carbonic material emersion was confirmed owing to the acceptable recyclability of more than ten cycles. The suggested platform can be used on large scale because of the simplicity in both preparation and regeneration approaches.

0D/3D Bi3TaO7/ZnIn2S4 heterojunction photocatalyst towards degradation of antibiotics coupled with simultaneous H2 evolution: In situ irradiated XPS investigation and S-scheme mechanism insight

Photocatalytic pollutant degradation coupled hydrogen generation via water splitting utilizing solar energy is a highly promising method for solving the problems of environment pollution and energy shortage. However, restricted utilization efficiency of solar energy and quick recombination of photogenerated carriers of catalysts have restricted its application in photocatalytic pollutant degradation coupled hydrogen evolution. In this work, we synthesized a 0D Bi3TaO7 nanodots-decorated 3D ZnIn2S4 nanoflowers photocatalyst using a simple two-step solvothermal method. The simultaneously photocatalytic degradation of antibiotics (tetracycline) coupled with hydrogen generation was efficiently realized over the resultant S-scheme ZnIn2S4/Bi3TaO7 composites. The relationship between S-scheme heterojunction photocatalysts and photocatalytic pollutant degradation coupled hydrogen evolution will be discussed. As a result, optimized ZB20 composite achieves highly efficient TC degradation rate >90% after ten cycles coupled with simultaneous H2 evolution (13.7 μmol g-1h−1) with Pt cocatalyst. Furthermore, interfacial transfer mechanism of S-scheme heterojunction photocatalysts will be carefully examined combining in-situ characterization techniques and DFT study.

Fabrication of 3D CuS@ZnIn2S4 hierarchical nanocages with 2D/2D nanosheet subunits p-n heterojunctions for improved photocatalytic hydrogen evolution

A 3D hierarchical nanocages photocatalyst CuS@ZnIn 2 S 4 with abundant and compact nanosheets 2D/2D hetero-interfaces showed an improved visible light photocatalytic performance for H 2 production in the absence of any cocatalyst. • This is the first report of the use of CuS nanosheets to assemble 3D nanocages. • The CuS@ZnIn 2 S 4 nanocages have compact nanosheets 2D/2D hetero-interfaces. • The nanocages photocatalyst displayed an improved hydrogen evolution rate. • The 2D/2D hetero-interfaces is favorable for carrier separation and transfer. Photocatalysis based on metal sulfide semiconductor is considered as an economic, safe, renewable, and clean technology. However, the availability of photocatalysts is limited by the low solar energy utilization efficiency and the fast recombination of photogenerated electron-hole pairs. Developing a hollow heterostructure photocatalyst based on semiconductors for enhancing solar energy utilization and separation efficiency of photogenerated carriers is crucial in the photocatalytic H 2 production reaction. The as-prepared 3D hierarchical nanocages photocatalyst CuS@ZnIn 2 S 4 with abundant and compact nanosheets 2D/2D hetero-interfaces displayed an improved photocatalytic hydrogen evolution rate as high as 7910 μmol h −1 g −1 in the absence of any cocatalyst. This is the first report of the use of CuS nanosheets-assembled hollow cubic cages to construct 3D hierarchical nanocages photocatalysts. The close distance between the two nanosheet subunits induce the strong interaction, which was advantage to the separation and transfer of charge carriers. In addition, the hollow structure can not only enhance light adsorption, but also suppress photogenerated carrier recombination. The experimental characterizations and theory calculations confirmed that the strong interaction between CuS and ZnIn 2 S 4 2D/2D hetero-interfaces can extremely facilitate the separation of photogenerated charge carriers and accelerate the electrons transfer. The present work provides a feasible method to construct heterojunction photocatalyst for hydrogen evolution via water splitting powered.