High Light Absorption Research Articles

Natural down fiber-reinforced and polypyrrole-modified silk fibroin composite aerogel for efficient solar steam generation toward seawater desalination and wastewater treatment

Poor mechanical properties and low photothermal efficiency of silk fibroin (SF)-based aerogels are current challenges that need to be addressed. Herein, SF composite aerogel was developed to enhance the mechanical properties through physical interpenetration of natural down fiber (Df) and hydrogen bonds formed among SF, Df, and polypyrrole (PPy) and to improve the evaporation performance via in-situ polymerization of PPy. The resultant Df/PPy@SF aerogel showed significant improvement of compressive stress (194.29 kPa), which was 6.96 times than that of SF aerogel (27.91 kPa), and also good compression resiliency. Furthermore, due to uniform distribution of PPy and high porosity of 95.27 %, Df/PPy@SF aerogel possessed high light absorbance of 99.87 % and low thermal conductivity (0.043 W·m−1·K−1). Thus, the Df/PPy@SF aerogel evaporator demonstrated high evaporation rates of 2.12 kg·m−2·h−1 for 3.5 wt% saline water, 2.04–2.15 kg·m−2·h−1 for various dye water, and 2.10 kg·m−2·h−1 for actual dye wastewater. Moreover, the developed aerogel exhibited evaporation stability and outstanding salt-resistance when treating seawater due to continuous water supply by superhydrophilic porous aerogel. Therefore, these findings demonstrate the excellent performance of Df/PPy@SF aerogel and will inspire further research on developing natural fiber-reinforced aerogels for use in the fields of solar water evaporation, energy, and other related applications.

Enhanced photoelectrocatalytic performance of ZnO/Co3O4 nanoflowers modified TiO2 nanotube array under visible light

The efficient degradation of organic pollutants from the water has been attracted greater public attention and remains to be the main challenge of environmental problems. In this work, ZnO/Co3O4 nanoflowers are deposited on the surface of TiO2 nanotube arrays (ZnCo-TiO2) via the one-pot hydrothermal method by adjusting the Zn/Co ratios. The images of scanning electron microscope show that the ZnCo11-TiO2 (the addition of the Zn/Co ratios is 1:1) presents nano spherical nano-flowers morphologies. In addition, the energy bandgap of ZnCo11-TiO2 is calculated to be 2.8 eV by UV–visible diffuse reflectance spectroscope, which was smaller than that of other semples. Moreover, the lowest peak intensity of photoluminescence spectroscopy for ZnCo11-TiO2 indicates that it has high electron-hole separation efficiency. From the results of UV–visible diffuse reflectance spectroscope and EIS, we can see that ZnCo11-TiO2 has a wider spectral absorption range (200–380 nm and 450–800 nm) and a smaller electron transfer impedance (137.4 Ω). The photoelectrocatalytic removal efficiencies of ZnCo11-TiO2 is 97.5% toward the removal of methylene blue (MB), which is higher than that of other semples. The excellent photoelectrocatalytic performances of ZnCo11-TiO2 are ascribed to the high visible light absorption and rapid transportation of photogenerated electrons on ZnO/Co3O4 nanoflowers. In addition, this paper tentatively stated the detailed photoelectrocatalytic mechanism of ZnCo11-TiO2 electrode for the removal of MB.

In-plane multiple heterogeneous Bi4O5I2/β-Bi2O3 nanoflowers with S-type scheme for efficient photocatalytic CO2 conversion

The assembly of heterogeneous photocatalysts with unique structures by 2D heterojunctions is an advanced strategy for efficient solar energy conversion. However, heterogeneous photocatalysts constructed from 2D materials will suffer from high photogenerated charge recombination and low light absorption due to the arbitrary stacking and weak bonding of lamellae. Here, flower-like Bi4O5I2/β-Bi2O3 (FL-Bi4O5I2/β-Bi2O3) heterojunctions are developed in situ using FL-δ-Bi2O3 as the starting material. It is noteworthy that the basic compositional form of the material was well maintained throughout the synthesis. Besides, due to the random reaction of iodide ions with the exposed surface of δ-Bi2O3, multiple heterogeneous regions are displayed on the basic lamellar units constituting the Bi4O5I2/β-Bi2O3 nanoflowers. Theoretical and experimental results reveal that FL-Bi4O5I2/δ-Bi2O3 possesses not only improved photogenerated carrier separation, enhanced light harvesting, but also considerable CO2 adsorption. Importantly, FL-Bi4O5I2/β-Bi2O3 achieves S-scheme CO2 conversion due to its reasonable energy band structure, and with the CO generation rate of up to 31.74 μmol g−1h−1 under simulated sunlight.

Guar Gum-Based Macroporous Hygroscopic Polymer for Efficient Atmospheric Water Harvesting.

Solar-driven atmospheric water harvesting technology has the advantage of not being limited by geography and has great potential in solving the freshwater crisis. Here, we first propose a purely natural and degradable superhydrophilic composite macroporous hygroscopic material by applying guar gum (GG) to atmospheric water harvesting. The material consists of GG-cellulose nanofibers (CNFs) as a porous substrate material, limiting the hygroscopic factor lithium chloride (LiCl) in its three-dimensional (3D) network structure, and carbon nanotubes (CNTs) play a photothermal conversion role. The composite material has a high light absorption rate of more than 95%, and the macroporous structure (20-60 μm) allows for rapid adsorption/desorption kinetics. At 35 °C and 90% relative humidity (RH), the moisture absorption capacity is as high as 1.94 g/g. Under 100 mW/cm2 irradiation, the absorbed water is almost completely desorbed within 3 h, and the water harvesting performance is stable in 10 cycles. Moreover, liquid water was successfully collected in an actual outdoor experiment. This work demonstrates the great potential of biomass materials in the field of atmospheric water collection and provides more opportunities for various energy and sustainable applications in the future.

Designing an isoelectronic counterpart to group III-V semiconductors: A novel honeycomb BeCN2 monolayer with ultra-high mobility toward solar driven overall water splitting and bifunctional oxygen evolution/reduction reaction

Like group III-V materials, which have obviously broadened the scope of group IV family and enriched the semiconducting members, a lightest representative of group II−IV−V2 family, BeCN2 monolayer, as an isoelectronic counterpart to group III-V semiconductor has for long remained unsolved for its applications in HER/OER/ORR, although previous first-principles investigations have touched the configuration and existence toward multiple crystalline forms of BeCN2. Using density functional theory calculations, the stable BeCN2 monolayer is predicted to be a direct bandgap semiconductor with high ultraviolet light absorption, achieving photocatalytic overall water-splitting within full pH, whose photogenerated electrons/holes will provide an external potential to obviously reduce the overpotential of HER and even make it achieve a spontaneous OER within pH 0–14. Meanwhile, it presents significantly anisotropic and high carrier mobilities (104 order) with preferred electron/hole transport along the x/y-direction, providing rich and required charge sources for HER/OER/ORR. After TM-decoration, the catalytic activities are greatly enhanced, achieved by the low HER and OER/ORR overpotentials of 0.05/0.07 V for V/Co@BeCN2 and 0.79/0.43 V for Ni@BeCN2, respectively. Plus, under pH 0–14, the OER overpotential of Ni@BeCN2 can be completely overcome by the external potential provided by photogenerated holes, achieving bifunctional catalysis for OER and ORR. Particularly, the Ni-d orbital is evidently hybridized with the O-p orbital for OH*Ni@BeCN2, so that the initial lone electrons located at the anti-bonding orbital pair up can populate the downward bonding orbital, allowing the species *OH to be moderately adsorbed on Ni@BeCN2, and thus redound the performance of OER/ORR.

Constructing 1D/0D Sb2S3/Cd0.6Zn0.4S S-scheme heterojunction by vapor transport deposition and in-situ hydrothermal strategy towards photoelectrochemical water splitting

Antimony sulfide (Sb2S3) is widely used in photocatalysts and photovoltaic cells because of its abundant reserves, low toxicity, environmental friendliness, narrow band gap, and high light absorption capacity. Sb2S3 shows a quasi-one-dimensional structure composed of [Sb4S6]n nanoribbons, a lot of reported studies are focused on preparing Sb2S3 with [hk1] oriented dominant growth to improve the photogenerated carrier transport capacity of Sb2S3. However, there is relatively few research on the preparation of [hk1] oriented rod-like Sb2S3 by vapor transport deposition (VTD) method. In this work, the VTD method was used to prepare Sb2S3 with [hk1] oriented growth on the FTO substrate, and then composite with the ternary solid solution CdxZn1−xS. Finally, a novel Sb2S3/Cd0.6Zn0.4S S-scheme heterojunction with rod-like core-shell structure was successfully constructed, which could effectively improve the photoelectrochemical properties. Because the solid solution component x is adjustable, that is, CdxZn1−xS has continuously adjustable band gap width and energy level position, the Sb2S3/CdxZn1−xS heterojunction type can be regulated from Type-II to S-scheme. Photoelectrochemical (PEC) tests indicated that the composite photoanode Sb2S3/Cd0.6Zn0.4S achieved a higher photocurrent density (2.54 mA·cm−2, 1.23 V vs. RHE), which is about 4.31 times that of pure Sb2S3 nanorod photoanode (0.59 mA·cm−2, 1.23 V vs. RHE).

Rapid degradation of Omeprazole and highly effective inactivation of E. coli in the UVA-light photocatalytic process with Cu-doped in spinel-structured ɣAl2O3 as a stable catalyst

Herein, a spinel alumina structure photocatalyst was prepared by a one-pot modified sol–gel technique with rational design and unique electronic structure evolution by Cu doping in the γAl2O3 lattice. Based on the obtained results of a full material characterization (incl. NH3-TPD, 27Al solid-state NMR, XPS, HAADF-STEM), the Cu-γAl2O3 xerogel nanomaterial displayed high dispersion of copper, significant quantities of high-density acid sites, an increase of the oxygen vacancies (OVs) on its surface, and high light absorption efficiency. This mesoporous Cu-γAl2O xerogel displayed brilliant photocatalytic performance under UVA-LED, owing to its suitable band gap, degrading around 92 % of 20 mg/L Omeprazole (OMP) in 30 min (pH = 7, catalyst = 50 mg/L). The effect of operating parameters was investigated, such as pH, concentration of Cu-ɣAl2O3/OMP, water matrix, and stability; the synthesized nanomaterial has shown outstanding stability and recyclability for four runs. The reaction mechanism was proposed using scavenging experiments, and EPR spectroscopy, Cu-doping-induced oxygen vacancies to promote charge separation and molecular oxygen activation, generating mainly ∙OH. The OMP degradation pathway was proposed (LC-MS), while the produced Cu-ɣAl2O3 nanomaterial effectively catalyzed the inactivation of >99.99 % E. coli.

Green recycling of waste poly(ethylene terephthalate) into Ni‐MOF nanorod for simultaneous interfacial solar evaporation and photocatalytic degradation of organic pollutants

AbstractInterfacial solar evaporation is regarded as the promising technology to mitigate freshwater scarcity. However, when polluted water is used, toxic pollutants might accumulate in the bulk water. Herein, we report the production of Ni‐MOF nanorod from waste poly(ethylene terephthalate) and fabricate bifunctional Ni‐MOF‐based evaporators. Owing to high light absorption and photothermal conversion, low thermal coefficient, and vaporization enthalpy, it shows an exciting evaporation rate (2.25 kg m−2 h−1) with good flexibility/durability, rated as one of most advanced evaporators. Density functional theory and COMSOL results show that the combination of nickel‐sites in Ni‐MOF and local heat plays a crucial role in peroxymonosulfate activation to produce reactive species. Thereby, it exhibits the high degradation activity of tetracycline. In outdoor, the freshwater production reaches 5.54 kg m−2 per day, and the tetracycline removal efficiency is 91%. This work provides a sustainable approach to produce solar evaporators capable of freshwater production and contaminant degradation.image

Ultra-broadband and wide-angle solar absorber with hierarchical nanohole design based on MXene

MXene has received a lot of attention from researchers in the fields of photothermal and photovoltaic due to its excellent optical properties. However, research on MXene-based solar absorbers has rarely been carried out. In this work, we proposed a MXene-based solar absorber with absorption broadband, wide-angle, and polarization insensitive. The absorber has excellent light capture capability, with its average absorption in the solar band as high as 97.8 % and an energy absorption ratio of 98.9 % in the AM1.5 solar radiation spectrum. The electric and magnetic field distributions indicate that the unique hierarchical nanohole design can effectively excite multiple resonance couplings of surface plasmon resonance, cavity resonance, and guided mode resonance. The proposed absorber can still maintain the broadband absorption characteristics within a certain manufacturing tolerances. Moreover, the absorber is insensitive to polarization and has a high light absorption under a large incident angle. We believe that this work holds great promise for solar thermal conversion and heat utilization.

Development of CeMnO2 and CeMnO2 buffer layer nanomaterials for CIGSSe/perovskite double-graded solar cells

Solar cells are a popular sustainable power source, but their electrical characteristics deteriorate over time due to a lack of UV light absorbent and wide energy bandgap buffer layer materials. Photon collecting in the UV wavelength band remains a difficult problem for making high-performance CIGSSe solar cells. Recently, several researchers have used CdS, Zn (O, S), ZnMnO, and ZnMgO buffer layer materials for making a CIGSSe solar cell. However, these buffer layers have various drawbacks, including a smaller energy bandgap, lower UV light absorption, and heavy metal toxicity. To solve the above problems, we used CeMnO2 buffer-1 and CeMgO2 buffer-2 as hole-reflected layer nanomaterials to create a high-efficiency CIGSSe/perovskite double-graded photovoltaic cell. The materials have a wide energy bandgap, high UV light absorption, and are toxic-free. First, we synthesized and characterized the CeMnO2 and CeMgO2 buffer layer materials; later, we used the extracted optical and electrical properties of both buffer layer nanomaterials to model a proposed high-efficiency solar cell numerically. X-ray diffraction (XRD) and scanning electron microscope (SEM) instruments have been used to confirm the average crystallite size, hexagonal cubic fluorite-like structure, surface characteristics, average particle size, and CeMnO2 and CeMgO2 nanomaterial morphology. The optical and electrical properties of both buffer layer materials are determined using ultraviolet–visible (UV–Vis) spectrophotometry and Hall Effect measurements. The study proposes a high-efficiency (SLG/Al/ZnMgO:Al/CeMnO2/CeMgO2/CIGSSe/MAFPbBrI/Mo) inorganic and organic solar cell using experimental data of CeMnO2 and CeMgO2 buffer layer nanomaterials. The bandgap energy increases from 3.68 to 3.86 eV for the CeMnO2 buffer-1 layer and from 3.578 to 3.865 eV for the CeMgO2 buffer-2 layer, and the device enhances photovoltaic characteristics, with an efficiency of 29.68 %, JSC of 39.37 mA/cm2, VOC of 873.9 mV, and FF of 86.28.

Effect of synthesis process steps on the structure and photocatalytic performance of ZnO–TiO2 composites

ZnO–TiO2 composites (Z@T and T@Z) were prepared by two processes. Z@T was to prepare ZnO particles first, and then TiO2 particles were prepared on the surface of ZnO; T@Z, in contrast, was to prepare TiO2 first and then ZnO. The samples were characterized by TG-DSC, XRD, SEM, EDS, UV–Vis, and PL spectra to explore the effects of synthesis process on the thermal effect, crystal structure, surface composition, energy band gap, recombination rate of photogenerated carriers, and photocatalytic performance of samples calcined at different temperatures. T@Z composites have an excellent crystal structure and effectively inhibit the recombination of photogenerated carriers. The T@Z prepared at 600 °C exhibited higher photocatalytic performance of methyl orange than that of ZnO, TiO2, and Z@T composites under UV light irradiation, which was about twice as large as that of Z@T calcined at 600 °C mainly due to the fact that T@Z composites possess rod and rice-like morphologies, high light absorption capability and low recombination rate of photogenerated carriers.

Photovoltaic ZnO/SnSx heterostructures obtained by “electrochemical deposition-successive ionic layer adsorption and reaction” approach

In this work, ZnO/SnS/indium tin oxide (ITO)/glass functional heterostructures have been developed using a combined approach of electrodeposition of a SnSx layer and successive ionic layer adsorption and reaction (SILAR) of the ZnO layer. The high-quality 400 nm-thick orthorhombic SnS0.9–0.95 films were formed on the ITO substrates with a thickness of 130 nm and an electrical conductivity of less than 40 Ω/□. Chemical deposition of ZnO thin films by the SILAR method allowed to deposit hexagonal films with a thickness of about 200 nm. The morphology, elemental and phase composition of the films were characterized by Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The band gap (1.4 eV for SnSx and 3.3 eV for ZnO), as well as the high light absorption coefficient of SnSx films (1–2) × 104 cm–1 were determined. The obtained ZnO/SnSx/ITO heterostructures formed by the electrodeposition–SILAR cycle showed a photoEMF value of 198 mV. These properties make ZnO/SnS heterostructure promising for low-cost solar cells based on affordable materials.

Enhanced Carrier Dynamics of CsPbBr3 Nanocrystals Enabled by Short-Ligand Ethanedithiol for Efficient Photoelectrocatalytic Photoanodes.

Photoelectrochemical (PEC) water splitting is a potential solution for a low-carbon society and clean energy storage due to its ability to produce hydrogen and oxygen. However, the slow oxidation half-reaction of the process has limited its overall efficacy, necessitating the development of an efficient photoanode. Colloidal CsPbBr3 nanocrystals (NCs) have been identified as promising candidates due to their high light absorption and valence band position. However, the presence of the electrical insulator, long-chain oleate molecules, on the surface of the CsPbBr3 NCs has hindered efficient charge carrier separation and transport. To solve this problem, short-chain 1,2-ethanedithiol (EDT) ligands were used to replace the oleate ligands on the surface of the CsPbBr3 NCs through a solid-state ligand exchange method. This resulted in a reduction of the nanocrystal spacing and a cross-linking reaction, which improved the photogenerated carrier separation and transport while still passivating the dangling bonds on the CsPbBr3 NC surface. Ultimately, this led to a remarkable photocurrent density of 3.34 mA cm-2 (1.23 VRHE), which was 5.2 times higher than that of the pristine oleate-CsPbBr3 NC (0.64 mA cm-2)-based device. This work presents an efficient way of developing inorganic lead halide perovskite colloidal nanocrystal-based photoanodes through surface ligand engineering.

High-speed and scalable combustion fabrication of ultralight carbon nanotube aerogels below air density

In this study, we introduce a fast, scalable method to fabricate ultralight carbon nanotube (CNT) aerogels with a bulk density (ρ) lower than air, using a combustion process. Typical fabrication methods for ultralight nanocarbon aerogels (ρ ≤ 1.0 mg cm−3) often involve intricate steps, such as high-temperature annealing and thermal reduction. These processes are time-consuming and pose scalability challenges. Here, we propose a high-speed fabrication process for ultralight CNT aerogels by combusting cellulose nanofibers (CNF) as a sacrificial template. The combustion process for CNT/CNF composite aerogels in an open environment takes only a few seconds, and the fabricated CNT aerogels with a lower-than-air density (ρ ≥ 0.48 mg cm−3) have high light absorption and good thermal and mechanical stability. We further illustrate the capability of these ultralight CNT aerogels to achieve levitation upon heating like a hot air balloon. Ultralight CNT aerogels capable of levitation by heating, fabricated by our fast and scalable method, hold the potential to replace traditional motor-driven unmanned aerial vehicles and conventional stratospheric platforms, such as high-altitude balloons, with sunlight-driven materials.

Ultra-wideband and wide-angle metamaterial absorber for solar energy harvesting from ultraviolet to near infrared

In this paper, an ultra-wideband solar absorber consisting of a four-layer structure of Al2O3-TiN-Al2O3-Ti is proposed. The proposed absorber achieves an average absorption of 97.85% in the wavelength range of 250–2000 nm (49.96% improvement over the reference planar structure), and its bandwidth of absorption over 90% is even as high as 1742 nm. As a result of the symmetrical design of the structure, the absorber has polarization insensitivity and wide-angle absorption characteristics. In particular, the absorber has a large process tolerance in the structural parameters and a high degree of universality for other metals and dielectric materials, which is highly advantageous in manufacturing. In addition, we explored the reasons for the high absorption of the structure in detail, discussed the influence of different structures on the absorption, and analyzed the absorption characteristics and thermal conversion efficiency of the structure under the solar spectrum. The proposed structure provides a broader bandwidth and higher light absorption than the recently reported work and further reduces the structure’s thickness. Therefore, the absorber will have broad application prospects in photothermal conversion, solar cells, imaging, and stealth.

Integrated carbonized corncobs solar steam generator with Janus structure

Solar steam generators are a highly economical and potential technology in seawater desalination. We benefit from the water transport principle of biomaterials and use corncobs as raw materials for carbonization. Drawing on the advantages of Janus structure, a solar thermal evaporator has been designed, with one side of untreated carbonized corncob and the other side of fluorosilane treated carbonized corncob, which can achieve an evaporation rate of 1.66 kg·m−2·h−1 under one sun solar irradiation and has a long cycling stability. The rich pore structure and high hydrophilicity of materials provide favorable conditions for water transportation; the high light absorption rate provides sufficient energy for photothermal conversion; the low thermal conductivity reduces heat loss; the surface hydrophobic treatment achieves interface heating while reducing water reflection on light. Thus, the performance of the evaporator with hydrophilic/hydrophobic Janus structures can be improved evidently. This work provides insights for efficient solar steam generators and is expected to be used in fields such as seawater desalination.

Popcorn-stick-like NH2-UiO-66/TiO2 nanotube nanocomposites toward optimized photocatalytic carbon oxidation with nitrogen dioxide

Developing photocatalytic technologies for pollutants removal with high harmless product selectivity is a significant challenge. Construction and optimization of nanocomposites junction with appropriate band alignments is an effective method for achieving this objective. Herein, a unique popcorn-stick-like NH2-UiO-66/TiO2 nanotube nanocomposites with staggered band alignment is fabricated. The small metal organic frameworks (MOFs) particles with diameters around 20 nm are uniformly dispersed on the surface of TiO2 nanoplates, creating a popcorn-stick-like structure. The resulting as-synthesized nanocomposites photocatalysts show distinguished photocatalytic activity for simultaneous removal of carbon particles and nitrogen dioxide with 100% NO2 conversion and 99% N2 selectivity, about 3.9 times higher than that of pristine TiO2. The significant enhancement is attributed to the rapid charge separation and transfer in TiO2 and NH2-UiO-66 interface and the visible light absorption. The enhanced charge transfer follows double charge transfer mechanism, which is confirmed by surface photovoltage spectroscopy, photoluminescence, transient photocurrent measurements, and electrochemical impedance spectroscopy. This study demonstrates the potential for the simultaneously removal of two pollutants using the composite of TiO2 and MOF materials with high surface area and visible light absorption ability, thereby providing the possible applications of NH2-UiO-66/TiO2 composites in environmental remediation including air purification and wastewater treatment.

Strong Intermixing Effects of LFO1-x/STOx toward the Development of Efficient Photoanodes for Photoelectrocatalytic Applications.

Aiming to improve the photocatalytic properties of transition metal perovskites to be used as robust photoanodes, [LaFeO3]1-x/[SrTiO3]x nanocomposites (LFO1-x/STOx) are considered. This hybrid structure combines good semiconducting properties and an interesting intrinsic remanent polarization. All the studied samples were fabricated using a solid-state method followed by high-energy ball milling, and they were subsequently deposited by spray coating. The synthesized compounds were demonstrated to possess orthorhombic (Pnma) and cubic (Pm3¯m) structures for LFO and STO, respectively, with an average grain size of 55-70 nm. The LFO1-x/STOx nanocomposites appeared to exhibit high visible light absorption, corresponding to band gaps of 2.17-3.21 eV. Our findings show that LFO0.5/STO0.5 is the optimized heterostructure; it achieved a high photocurrent density of 11 μA/cm2 at 1.23 V bias vs. RHE and an applied bias photo-to-current efficiency of 4.1 × 10-3% at 0.76 V vs. RHE, as demonstrated by the photoelectrochemical measurements. These results underline the role of the two phases intermixing LFO and STO at the appropriate content to yield a high-performing photoanode ascribed to efficient charge separation and transfer. This suggests that LFO0.5/STO0.5 could be a potential candidate for the development of efficient photoanodes for hydrogen generation via photoelectrocatalytic water splitting.

In situ polymerization of three-dimensional polypyrrole aerogel for efficient solar-driven interfacial evaporation and desalination

Solar-driven interfacial evaporation (SIE) and desalination is a promising approach to mitigate the scarcity of freshwater resources. Here, a three-dimensional polypyrrole (3D PPy) aerogel was prepared by in situ polymerization of pyrrole to serve as an independent evaporator. The interconnected pore structure and super-hydrophilicity enabled PPy evaporators with rapid water transport to the top interface (< 5 s). The hydrogen interaction between polymer chains and water molecules induced large amount of intermediate water, thereby reducing the evaporation enthalpy of water in PPy aerogels. As a result, the optimized PPy aerogel attained an evaporation rate of 2.90 kg m−2 h−1 and an energy conversion efficiency of 114% under 1 sun irradiation. Moreover, the generated steam can be accelerated by the convection and an evaporation rate as high as 6.10 kg m−2 h−1 was realized at 2.5 m s−1. The rapid water transport also enabled PPy aerogel with high-efficiency of self-salt-discharge and efficient desalination for 3.5 wt% brine under 2.5 m s−1. In the outdoor SIE experiment, the excellent evaporation performance was achieved at 12:40 (7.04 kg m−2 h−1 under 74.2 mW cm−2 of solar intensity and 2.5 m s−1 of convective flow), and the cumulative evaporation of 41.50 kg m−2 for successive 9 h was obtained. After the evaporation of simulated seawater and heavy metal wastewater, the concentration of collected fresh water could be reduced about 2–3 orders of magnitude. This 3D PPy evaporation platform with high light absorption, porous structure, super-hydrophilic property, effective steam diffusion, and excellent salt resistance provides an effective way to develop advanced solar-driven water treatment technology.

Interfacial modulation of α-Ag1.82Cu0.09WO4 with high active BiOClxI1−x for boosting photocatalytic activity and degradation of emerging contaminants under direct sunlight

Removal of organic contaminants in wastewater using sunlight-driven photocatalysts has received significant attention in recent years. However, the rational design of photocatalysts to attain high light absorption, lower charge carrier recombination with efficient photocatalytic activity and good recycling capability is crucial for the practical photocatalysis process. Herein, solid-state Z-scheme BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 heterojunction is synthesized by assembling hierarchical 3D-BiOCl0.6I0.4 nanoflowers on cube-like 3D-α-Ag1.82Cu0.09WO4 surface through a hydrothermal method. A wide range of characterization techniques confirms the successful synthesis of BiOClxI1−x (0 ≤ x ≤ 1.0), α-Ag1.82Cu0.09WO4 and BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 binary composites. The TC antibiotic removal efficiency of 30 wt% BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 binary composite reaches 95.91% within 120 min under natural sunlight irradiation and the rate constant is 1.81 and 3.33 times higher than the pristine BiOCl0.6I0.4 and α-Ag1.82Cu0.09WO4, respectively. The optimized binary heterojunction exhibits excellent photocatalytic performance for toxic pollutants like MB (η = 97.27%) and RhB (η = 95.75%) under direct sunlight irradiation. The favorable photocatalytic activity of binary heterojunction is ascribed to enhancing the sunlight absorption range, the tight contact interface and the effective separation of electron/hole pairs. Notably, 30 wt% BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 binary composite exhibits attractive recycling ability and good photostability for prolonged sunlight irradiation. Furthermore, the total organic carbon results also confirm that the 30 wt% BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 efficiently mineralized the model pollutants (TC antibiotic, MB and RhB) into other unharmful compounds under sunlight irradiation. In summary, this work offers an effective strategy to prepare solid-state Z-scheme heterojunction with favorable photocatalytic activity, which can increase wastewater purification efficiency.