Matched Energy Band Research Articles

P/i interfacial engineering in semi-transparent silicon thin film solar cells for fabrication at a low temperature of 150 °C

In this study, we aimed to develop semitransparent solar cells (STSCs) using hydrogenated amorphous silicon (a-Si:H) at a low temperature of 150 °C to support the fabrication of flexible solar modules, applicable in building-integrated photovoltaics (BIPV). To compensate for the presumable loss of device performance at such a low processing temperature, careful control of the p/i interface is proposed. We fabricated buffer layers with hydrogen (H2)/silane (SiH4) gas flow ratios (R) ranging from 4 to 16 (R4–R16) to investigate their characteristics and incorporate them at the p/i interface by considering energy band matching. By employing this buffer, the power conversion efficiency (PCE) of a STSC was improved from 4.83% to 5.57% which is the best record in a-Si:H STSCs processed at a low temperature of 150 °C. This p/i interfacial buffer can support the realization of flexible a-Si:H-based BIPV systems using plastic- or polymer-based substrates.

In-situ construction of Bi2SiO5/BiOBr heterojunction with significantly improved photocatalytic activity under visible light

To further improve the light response range and photocatalytic activity of Bi2SiO5, the Bi2SiO5/BiOBr type-II heterojunction photocatalysts were constructed by in-situ partial ion exchange strategy using Bi2SiO5 as precursor. The crystal phases, morphologies, chemical compositions, optical properties and textural structures of as-synthesized Bi2SiO5/BiOBr photocatalysts were characterized by the corresponding analytical techniques. The photocatalytic activities of samples were evaluated by degrading Rhodamine B (RhB) solution under visible light irradiation. The results showed that the Bi2SiO5/BiOBr heterojunction photocatalysts significantly improved the photocatalytic performances, which would be ascribed to the extended light response, enhanced adsorption capacity, matched energy band structures and intimate interface contact. Construction of Bi2SiO5/BiOBr heterojunction facilitated the separation and transfer of photoexcited charge carriers, which were verified by the electrochemical impedance spectroscopy (EIS), transient photocurrent response and steady photoluminescence spectroscopy (PL) measurements. This work would offer a new insight into the design and preparation of Bi2SiO5-based heterojunction photocatalysts for the removal of organic contaminant.

Fabrication of p-n CuBi2O4/MoS2 heterojunction with nanosheets-on-microrods structure for enhanced photocatalytic activity towards tetracycline degradation

Abstract Semiconductor-based photocatalytic oxidation technology represents a promising strategy for clean, low-cost, and environmental friendly to solve the water pollution problems by utilizing solar energy. Herein, p-CuBi2O4/n-MoS2 as a noble-metal-free efficient visible-light driven composite was successfully synthesized via a simply one-pot hydrothermal method, which possessed the unique nanosheets-on-microrods heterostructure. Based on the experimental data analysis, with the assistance of MoS2, the absorption band of the prepared heterojunction becomes broader and covers the entire visible region. And the highest photocatalytic activity for the degradation of tetracycline was achieved when introducing ~5% weight ratio of MoS2 in the composite (76%, 120 min), which is about 2.79 and 2.96 times than that of MoS2 and CuBi2O4, respectively. And the improvement of the photocatalytic activity of the p-CuBi2O4/n-MoS2 derives from the energy band matching and the formation of the built-in electric field. This work will open opportunities for designing the high-efficient CuBi2O4-based p-n heterojunction photocatalysts and would be of great significance to satisfy ever-increasing environmental demands in the future.

P-n-Sensitized Heterostructure Co3O4/Fullerene with Highly Efficient Photoelectrochemical Performance for Ultrasensitive DNA Detection.

Significantly sensitized architectures meeting the requirements of high photoelectric conversion efficiency and promising photocurrent intensity are extremely desirable, but challenges in sensitizer development and efficiency in photoelectrochemical (PEC) fields remain. In this paper, the p-type metal oxide semiconductor Co3O4 was attached as an effective photosensitizer to n-type fullerene C60 in view of appropriately matched energy band levels to form the highlighted p-n-sensitized heterostructure Co3O4/fullerene, with facilitated charge separation and accelerated carrier mobility. Compared with traditional p-n heterostructure, the p-n-sensitized heterostructure Co3O4/fullerene illustrated a wider range for light absorption with further enhanced light-harvesting capability, thereby leading to more exceptional PEC performance containing remarkably promoted photoelectric conversion efficiency and improved photocurrent intensity. Impressively, the photocurrent intensity obtained by Co3O4/fullerene was about sixfold higher than that of fullerene alone, and this achievement was quite favored compared to the reported works for fullerene sensitization, which could be responsible for the advancement of detection sensitivity for the subsequently constructed biosensor. Unambiguously, given the p-n-sensitized heterostructure Co3O4/fullerene of high PEC activity, the well-fabricated three-dimensional DNA walker applied as a target-cascade signal amplification strategy, and the Au layer employed as the specific linker between the photoactive material and the signal amplification product, a smart PEC biosensor was successfully enabled for ultrasensitive investigation of the model DNA (a fragment of the p53 gene), showing a wide linear range of 60 to 1 × 105 aM and a detection limit of 20 aM. This proposed PEC biosensor provided acceptable insights into the clinic analysis, disease therapies, and other relevant subjects.

Construction of novel ternary dual Z-scheme Ag3VO4/C3N4/reduced TiO2 composite with excellent visible-light photodegradation activity

Abstract

Dual functionality of K0.3WO3/Ag2O nanocomposites for smart window: Energy saving and visible photocatalytic self-cleaning performance

Series of novel K0.3WO3/Ag2O nanocomposites were successfully prepared by simple two steps method. An exciting fact that near-infrared light shielding and visible photocatalytic self-cleaning effects are integrated into the K0.3WO3/Ag2O film (weight ratio of K0.3WO3 to Ag2O = 30) could offer significant potential applications in smart windows. Furthermore, the optical properties and photocatalytic activity of the composites could be tuned by adjusting the weight ratio of K0.3WO3 to Ag2O. The obtained K0.3WO3/Ag2O films presented enhanced photocatalytic self-cleaning performance compared with pure K0.3WO3 under visible light irradiation. The improved self-cleaning performance of the K0.3WO3/Ag2O composites was ascribed to a combined contribution of the matched energy band structures and boosted separation efficiency of photo-generated carriers. An approximately 2.3°C-3.4 °C decrease in inner temperature was obtained for the heat box covered with K0.3WO3/Ag2O coated glass. Therefore, the proposed K0.3WO3/Ag2O (weight ratio of K0.3WO3 to Ag2O = 30) smart coating is a promising material for self-cleaning energy-saving windows.

A generic strategy for preparation of TiO2/BixMyOz (M = W, Mo) heterojunctions with enhanced photocatalytic activities

Use of nanoscale TiO2/BixMyOz (M = W, Mo) heterojunctions is one of the most promising strategies for improving the photocatalytic efficiency. However, the controllable synthesis and morphology modification of these heterojunctions are still highly challenging. In this work, we developed a generic approach to hydrothermally synthesize TiO2/BixMyOz heterojunctions and tailor their morphologies. The key to this strategy is to intentionally utilize the surface defects of TiO2 as highly active sites to adsorb the intermediate hydrolysis-products, which is in marked contrast to the conventional direct precipitation methods. In the subsequent hydrothermal reactions, MO42− replaced the hydroxyl and nitrate radicals to form stable TiO2/BixMyOz heterojunctions, in which the second phase BixMyOz occupied the defect sites of TiO2 nanobelts. Under visible light irradiation, the photocatalytic reaction rate constant of TiO2/Bi2WO6 heterojunctions was four times higher than that of single phase Bi2WO6 nanosheets, while the photocatalytic reaction rate constant of TiO2/Bi3.64Mo0.36O6.55 heterojunctions exhibited a seven-fold increase compared with Bi3.64Mo0.36O6.55 nanopaticles. The substantial enhancement of photocatalytic activity is primarily ascribed to the matching energy band structure in the TiO2/BixMyOz heterojunctions, which is able to improve the separation efficiency of photo-generated electron-hole pairs and prolong the lifetime of charge carriers in the heterojunctions.

Perovskite light-emitting diodes based on n-type nanocrystalline silicon oxide electron injection layer

Organometal halide perovskites featuring solution-processable characteristics, high photoluminescence quantum yield (PLQY), and color purity, are an emerging class of semiconductor with considerable potential applications in optoelectronic devices. Electron injection layer is an important component of perovskite light-emitting device, which determines the growth of perovskite film directly. In this paper, the perovskite light-emitting diodes (PeLEDs) based on n-type nanocrystalline silicon oxide (n-nc-SiO<sub><i>x</i></sub>:H) electron injection layer are designed and realized. This novel electron injecting material is prepared by the plasma enhanced chemical vapor deposition (PECVD), and its smooth surface and matched energy band result in superior perovskite crystallinity and low electron injection barrier from the electron injecting layer to the emissive layer, respectively. However, the external quantum efficiency (EQE) of PeLED is as low as 0.43%, which relates to defects and leakage current due to the incomplete surface coverage of perovskite film. The fast exciton emission decay (< 10 ns) stems from strong non-radiative energy transfer to the trap states, and represents a big challenge in fabricating high-efficiency PeLEDs. In order to obtain desirable perovskite film morphology, an excessive proportion of methylammonium bromide (MABr) is incorporated into the perovskite solution, and a volume of benzylamine (PMA) is added into the chlorobenzene antisolvent. The perovskite films suffer low PLQY and short PL lifetime if only MABr or PMA is introduced. When the molar ratio of MABr is higher than 60%, the luminescence quenching arising from Joule heating is depressed by employing PMA, contributing to a higher PLQY (> 30%) and a longer carrier lifetime. The synergistic effect of MABr and PMA increase the coverage and reduce the trap density of perovskite film, inhibit the luminescence quenching in the annealing process, and thus facilitating the perovskite film with higher quality. Finally, the n-i-p PeLED exhibits green-light emission with a maximum current efficiency of 7.93 cd·A<sup>-1</sup> and a maximum EQE up to 2.13% is obtained. These facts provide a novel electron injecting material and a feasible process for implementing the PeLEDs. With further optimizing the perovskite layer and device configuration, the performance of n-i-p type PeLEDs will be improved significantly on the basis of this electron injection material.

SnS2 nanosheets coupled with 2D ultrathin MoS2 nanolayers as face-to-face 2D/2D heterojunction photocatalysts with excellent photocatalytic and photoelectrochemical activities

In this work, ultrathin 2D SnS2 nanosheets were coupled with 2D MoS2 nanolayers as face-to-face 2D/2D heterojunction photocatalysts. Compared with pristine SnS2, this face-to-face 2D/2D SnS2/MoS2 heterojunction exhibited obvious improvement in photocatalytic and photoelectrochemical performance. The highest heterojunction composite activity was nearly two times and 12 times than that of pristine SnS2 in photocatalytic activity and photoelectrochemical performance, respectively. The good performance was ascribed to the face-to-face 2D/2D heterojunction structure and suitable energy band matching. In this face-to-face 2D/2D heterojunction structure, the migration distance between the photoinduced carriers' separation site to the heterojunction interface was very short, but the contact surface was large. Furthermore, the conduction band position of MoS2 was more positive than that of SnS2. Therefore, the photoinduced electrons at the conduction band of SnS2 could flow into the conduction band of MoS2. The transmission between the SnS2/MoS2 heterojunction prolonged the carriers' life and improved the carriers' separation efficiency. In this way, photoinduced carriers produced in SnS2 and MoS2 could flow across the heterojunction quickly, which increased the carriers' separation efficiency. This work successfully developed a new structure to improve the heterojunction property for photocatalytic applications.

MnS coupled with ultrathin MoS2 nanolayers as heterojunction photocatalyst for high photocatalytic and photoelectrochemical activities

Nano-MnS were coupled with ultrathin two-dimensional MoS2 nanolayers as heterojunction photocatalysts. The well heterojunction contact can be confirmed by high resolution TEM images. The heterojunction composites display higher absorption intensity of visible light and the S XPS peaks show obvious shift. Compared with pristine MnS, this MnS/MoS2 heterojunction exhibited vast enhancement in photocatalytic and photoelectrochemical performance. The heterojunction composite with highest activity displayed 161% enhancement in photocatalytic activity, 2.6–11.5 times increase of photocurrent density. This vast improvement can be assigned to the energy band matching of MnS/MoS2 heterojunction. Both the conduction band and valence band of MnS are more negative than those of MoS2, the photo-induced electrons at the conduction band of MnS will transfer into the conduction band of MoS2 while the photo-induced holes at the valence band of MoS2 will transfer into the valence band of MnS. In this way, the photo-produced carriers will flow into different semiconductors and the carriers' separation efficiency is enhanced. The work develops a new approach to improve the heterojunction property for photocatalytic and photoelectrochemical application.

High-Performance Silicon-Compatible Large-Area UV-to-Visible Broadband Photodetector Based on Integrated Lattice-Matched Type II Se/n-Si Heterojunctions.

A gold-induced NH4Cl-assisted vapor-based route is proposed and developed to achieve vertically aligned submicron Se crystals on lattice-matched (111)-oriented silicon substrates, based on which a high-performance large-area silicon-compatible photodetector is constructed. Thanks to the energy band structure and the strongly asymmetrical depletion region, the fabricated Se/Si device maintains a similar wavelength cutoff to that of selenium devices before the IR region, along with a high-performance broadband photoresponse in the UV-to-visible region. The large-area photodetector maintains avery low leakage current under a -2 V bias, and a high on/off ratio of 103-104 is obtained with a high photocurrent of 62 nA at 500 nm. A photoresponse is clearly observed when the bias voltage is removed. The pulse response precisely provides a high response speed (τrise + τfall ≈ 1.975 ms), exceeding the fastest Se-based photodetectors in current reports. The enhanced photoelectric properties and the self-power photoresponse mainly derive from the integrated high-quality Se/n-Si p-n heterojunctions with both lattice match and type II energy band match.

Using SiO2/PDA-Ag NPs to dual-inhibited photoelectrochemical activity of CeO2-CdS composites fabricated a novel immunosensor for BNP ultrasensitive detection

A novel sandwich photoelectrochemical (PEC) immunosensor was constructed for ultrasensitive brain natriuretic peptide (BNP) detection. In this work, CeO2-CdS was employed as excellent photoactive sensing platform, and SiO2/PDA-Ag nanocomposite was used as signal amplification element. CeO2-CdS, providing great photocurrent response due to the well matched energy band which effectively impeded the recombination of the electrons and holes. For SiO2, due to the poor electro-conductivity and easy modification, it could be well used as an excellent signal-off label. For the sake of improving sensitivity of the immunosensor, Ag nanoparticles (Ag NPs) was applied owing to the energy transfer between CdS, which could decrease the PEC response obviously for amplifying the change of signal value. Besides, Ag NPs could anchor plenty of the detection antibodies by the chemical bonding between Ag NPs and –NH2 of antibodies. Using PDA to connected SiO2 and Ag NPs because of it great biocompatibility and reducing capacity. The well-established PEC immunosensor exhibited a low detection limit of 0.05 pg mL−1 (S/N = 3) with a linear range from 0.1 pg mL−1−5 ng mL−1 for BNP detection. In addition, the immunosensor also exhibited good stability, satisfactory reproducibility and acceptable specificity, which could be applied to detect other biomarkers.

(Invited) High Efficiency and Low Hysteresis Solar Cells Based on Perovskite with Triple Cation and Mixed Pb-Sn

Perovskite solar cells (PSCs) based on organometallic halide have received wide attention and been developed rapidly in recent years, the highest power conversion efficiency (PCE) have reached 22.1%. However, these materials contain lead (Pb), which is toxic. It is of critical importance to find new elements for partially or completely replacing Pb to reduce the Pb contents. Most works carried out focused on CsSnX3 (X=I, Br), FASnX3 (X=I, Br), (FASnI3)1-x(MAPbI3)x (x=0-1), MASnxPb1-xI3 (x=0.25, 0.5), FA0.75Cs0.25Pb0.5Sn0.5I3, etc. We substitute PbI2 with SnI2 in Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3 material for the first time, through changing the ratio of Pb and Sn, which can regulate the size of grains. By optimizing the ratio of PbI2 and SnI2 to achieve the best energy band matching, a power conversion efficiency of 16.10% is achieved by using Cs0.05FA0.79(Pb0.6Sn0.4)0.84I2.5MA0.16Pb0.16Br0.5 as perovskite light absorption layers. With bandgap changing, the hysteresis of the PSCs showed regular variation. Under the optimal bandgap matching, the planar heterojunction PSCs exhibit J-V curves with negligible hysteresis. Figure 1. a)-f) The reverse and forward voltage scans of Cs0.05FA0.79(Pb1-xSnx)0.84I2.5MA0.16Pb0.16Br0.5 (x=0, x=0.1, x=0.2, x=0.3, x=0.4, x=0.5) perovskite solar cells. Figure 1

In-situ construction of direct Z-scheme Bi2WO6/g-C3N4 composites with remarkably promoted solar-driven photocatalytic activity

As metal-free visible light-driven semiconductor, graphitic carbon nitride (g-C3N4) has attracted increasing attention owing to its excellent properties. However, the photocatalytic performance of the bare g-C3N4 has been significantly hampered by its inherent drawbacks. Herein, to further boost the photocatalytic performance of g-C3N4, Bi2WO6 was in-situ successfully anchored onto g-C3N4 via a routine hydrothermal method. The as-prepared Bi2WO6/g-C3N4 heterojuctions display highly efficient photocatalytic activity toward decay of rhodamine B (RhB) and phenol aqueous solution under simulated sunlight irradiation. When the molar ratio of Bi:g-C3N4 was 4%, the Bi2WO6/g-C3N4 sample prepared exhibits highest photocatalytic activity. The highest photocatalytic performance of the 4% sample can be definitely attributed to the highest separation rate of the photogenerated electron-hole pairs, supported by the results of surface photovoltage spectroscopy (SPS). The cycling experiments show that Bi2WO6/g-C3N4 composites display excellent stability. The photoinduced electron-hole separation and transfer of the Bi2WO6/g-C3N4 composites obey a direct Z-scheme mechanism based on the matched energy band, the analysis of main active species and the enhanced separation rate of photogenerated electron-hole pairs.

Incorporation of CoO nanoparticles in 3D marigold flower-like hierarchical architecture MnCo2O4 for highly boosting solar light photo-oxidation and reduction ability

Most previous reported photocatalysts designs show that, either photocatalytic oxidation (PCO) or reduction (PCR) is inhibited due to the insufficient govern of the photo-excited h+ and e−. To overcome this problem, we consider that both PCO and PCR could be improved simultaneously by employing suitable photocatalyst. Herein, the novel 3D marigold flower-like hierarchical architecture CoO@MnCo2O4 was successfully synthesized by anchoring CoO nanoparticles (NPs) on MnCo2O4 flower using a facile solvothermal method followed thermal annealing treatment under N2 atmosphere for the first time. This strategy relies on the formation of a p-n heterostructure with matching energy band gaps, in which CoO NPs tightly adhere to the surface of hierarchical MnCo2O4 microflowers, and the flower-like MnCo2O4 act as scaffold to disperse CoO NPs. The as-fabricated CoO@MnCo2O4 hybrid not only presented remarkable performance for PCO of tetracycline (TC) but also exhibited excellent PCR of hexavalent chromium (Cr (VI)) under visible light irradiation. Meanwhile, the photocatalyst also can be used for treatment a mixture of them and exhibited promoted photocatalytic efficiency. That's the primary reason that h+ and e- can play their own roles to accomplish PCO and PCR, respectively. Moreover, the unique 3D hierarchical microflowers structure not only provide a higher specific surface area, sufficient active sites and enhanced light harvesting, but also significantly decrease the aggregation of CoO particles. The appearance photocatalytic mechanism of the p-n heterostructure system was also discussed in detail. The facile synthesis strategy and outstanding photocatalytic performance make the 3D hierarchical architecture CoO@MnCo2O4 a promising candidate as a visible light photocatalyst.

Rapid degradation of naproxen by AgBr-α-NiMoO4 composite photocatalyst in visible light: Mechanism and pathways

A novel strategy for fabrication of visible light driven AgBr-α-NiMoO4 composite photocatalyst has been developed, including microwave hydrothermal and precipitation-deposition method. The fabrication of heterojunction photocatalyst was proved by XRD, FESEM mapping, HRTEM, SAED, EDS, and XPS techniques. The composite photocatalyst degraded naproxen drug around 84% within 20 min under visible light irradiation. The active species trapping experiment confirmed that OH, O2−, and h+ play a crucial role for naproxen degradation. Due to efficient charge separation, well matched energy band of AgBr and α-NiMoO4 as well as surface plasmon resonance of silver particles, the composite revealed the high photocatalytic performance with excellent stability up to fifth cycle. In addition, the composite is photochemical stable. Furthermore, the five degradation pathways were proposed on the basis of retention time and theoretical/observed molecular masses of 19 degraded organic fragments that was confirmed by high-performance liquid chromatography-photodiode array (HPLC-PDA) and high resolution-quadruple time of flight electrospray ionization mass spectroscopy (HR-QTOF ESI/MS) techniques. The different reactions (methylation, demethylation, decarboxylation, hydroxylation, oxidation, and coupling) were observed during NPX degradation by photocatalyst. TOC (total organic carbon) analysis revealed that naproxen drug was completely mineralized by composite photocatalyst within 100 min. So, this work represents the fabrication of visible light induced novel composite photocatalyst for rapid degradation of pharmaceutical pollutant with detailed mechanism and pathways.

A sensitive signal-on photoelectrochemical sensor for tetracycline determination using visible-light-driven flower-like CN/BiOBr composites

As a broad-spectrum antibiotic, tetracycline (TC) is widely used in agricultural purposes and human therapy. More attention is paid to TC as a serious threat to human health, including the fast spreading of antibiotic resistance gene and the serious toxicity to aquatic organisms. Therefore, the timely and accurate determination of TC residues is an urgent task to protect the safety of human. Herein, an effective and facile photoelectrochemical sensor platform based on carbon nitride/bismuth oxyhalide (CN/BiOBr) composites can be constructed for monitoring TC. The flower-like CN/BiOBr composites are prepared via a simple one-pot ethylene glycol-assisted solvothermal process with the addition of ionic liquid 1-hexadecyl-3-methylimidazolium bromide ([C16mim]Br). In view of matched energy band positions of CN and BiOBr, the addition of CN can reduce the recombination of photogenerated electron-hole pairs and improve the efficiency of visible light utilization, leading to enhancing photoelectrochemical response of BiOBr. Under light excitation, the photocurrent of CN/BiOBr composites is drastically improved, which is 6 times as much as that of pure BiOBr. Considering the superior photoelectrochemical performance, a photoelectrochemical sensor for monitoring TC has been developed, displaying linearly enhanced photocurrent with increasing the TC concentration. Two linear relationships received are from 8.0 to 4.0 × 102 ng mL−1, and 4.0 × 102 to 5.2 × 103 ng mL−1, respectively. The detection limit is 3.8 ng mL−1. The photoelectrochemical sensor exhibits a series of benefits including excellent stability, a wide linear range, a low detection limit and good anti-interference ability. Therefore, this work may offer great promises in providing a universal and efficient photoelectrochemical sensor for the tetracycline detection, and pave the way of constructing more materials used in photoelectrochemical detection field.

Enhanced charge separation and transfer by Bi2MoO6@Bi2Mo2O9 compound using SILAR for photoelectrochemical water oxidation

The successive ionic layer absorption and reaction (SILAR) method has been successfully used for the thin film preparation of metal oxides. In this work, we firstly fabricate the hybrid Bi2MoO6@Bi2Mo2O9 photoanode by a one-step SILAR method. The optimized Bi2MoO6@Bi2Mo2O9 demonstrates a photocurrent about 0.160 mA cm−2 at 1.23 V vs. RHE, which is 3.6 and 8.0 times enhancement compared with pristine Bi2MoO6 and Bi2Mo2O9 for water oxidation. The enhanced efficiencies of charge separation and oxidation kinetics by Bi2MoO6@Bi2Mo2O9 are 20.5% and 54.6% at 1.23 V vs. RHE, which is higher than Bi2Mo2O9 (9.2% and 15.4%) and Bi2MoO6 (10.7% and 29.2%). Moreover, the electron transport time of Bi2MoO6@Bi2Mo2O9 is 0.038 ms at 300 W m−2 through the controlled intensity modulated photocurrent spectrometer analysis, which is lower than Bi2Mo2O9 (0.087 ms) and Bi2MoO6 (0.052 ms). The enhanced photoelectrochemical activities of Bi2MoO6@Bi2Mo2O9 can be attributed to the matched energy band between Bi2Mo2O9 and Bi2MoO6, which could not only improve the charge separation, but also accelerate the charge migration. Therefore, our research indicates an effective technique for fabricating Bi2MoO6@Bi2Mo2O9 by one step process, and thus may provide a new idea for the preparation of other hybrid ternary metal oxides.

Construction of 2D/2D layered g-C3N4/Bi12O17Cl2 hybrid material with matched energy band structure and its improved photocatalytic performance.

A series of visible-light-induced 2D/2D layered g-C3N4/Bi12O17Cl2 composite photocatalysts were successfully synthesized by a one step chemical precipitation method with g-C3N4, BiCl3 and NaOH as the precursors at room temperature and characterized through XRD, FTIR, XPS, TEM, BET and UV-vis DRS measurements. The results of XRD, FTIR and XPS indicated that g-C3N4 has been introduced in the Bi12O17Cl2 system. The TEM image demonstrated that there was strong surface-to-surface contact between 2D g-C3N4 layers and Bi12O17Cl2 nanosheets, which contributed to a fast transfer of the interfacial electrons, leading to a high separation rate of photoinduced charge carriers in the g-C3N4/Bi12O17Cl2 system. Rhodamine B was considered as the model pollutant to investigate the photocatalytic activity of the resultant samples. The g-C3N4/Bi12O17Cl2 composite showed a clearly improved photocatalytic degradation capacity compared to bare g-C3N4 and Bi12O17Cl2, which was ascribed to the interfacial contact between the 2D g-C3N4 layers and Bi12O17Cl2 sheet with a matched energy band structure, promoting the photoinduced charges' efficient separation. Finally, combined with the results of the trapping experiment, ESR measurements and the band energy analysis, a reasonable photocatalytic mechanism over the 2D/2D layered g-C3N4/Bi12O17Cl2 composite was proposed.

A green approach for the synthesis of novel Ag3PO4/SnO2/porcine bone and its exploitation as a catalyst in the photodegradation of lignosulfonate into alkyl acids.

A novel Ag3PO4/SnO2/porcine bone composite photocatalyst was successfully prepared via an ion exchange method, which can convert lignin derivatives into small molecular acids upon exposure to visible light at room temperature at ambient pressure. The composition characterization, optical absorption properties and photocatalytic activities of the Ag3PO4/SnO2/porcine bone composites were thoroughly investigated. The certain role of each component of the composites in the degradation reaction was discussed: Ag3PO4 acted as the major active component, while SnO2 and porcine bone as cocatalyst contributed to improve the photocatalytic activity and stability of Ag3PO4. The enhanced activity of the Ag3PO4/SnO2/porcine bone composite may be attributed to the synergistic effect including the matched energy band structures of Ag3PO4 and SnO2 for the decrease in the probability of electron–hole recombination and improved performance in the presence of hierarchical porous porcine bone (hydroxyapatite). This paper also analyzed the change of the molecular weight and structure of sodium lignin sulfonate in the photocatalytic reaction and discussed the possible photocatalytic mechanism of the photocatalyst composite, indicating that the benzene rings of guaiacol were oxidized into different alkyl acids (maleic acid, oxalic acid, formic acid and methoxy acetic acid).