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Micro/mesoporous Zn2GeO4with crystalline pore-walls was successfully synthesized viaa simple ion exchange method at room temperature. This structure showed enhanced activity in photoreduction of CO2in comparison with Zn2GeO4prepared by a solid state reaction. [ABSTRACT FROM AUTHOR]

Exploring nonmetallic plasmonic materials is desirable yet challenging. For a long time, free‐plasmonic semiconductor is difficult to be used in high‐sensitive surface‐enhanced Raman spectrum (SERS) due to poor enhanced factor and high‐fluorescent background. Herein, it is reported that a nonmetallic plasmonic SERS chip, constructed with a highly ordered sub 1 nm WO3−x nanowire‐based superstructure, shows multicomponent detection capability. The densely arranged nanowires enable a strong localized surface plasmon resonance due to the high charge carriers' density induced by oxygen vacancies in the nanowires. In addition to the usual charge‐transfer enhancement, such nonmetallic WO3−x displays a unusual dramatic plasmon‐enhanced SERS sensing performance with a detection limit of 10−10m and a maximum Raman enhanced factor of 8.3 × 107. The substrate fluorescence signals are efficiently quenched, making the SERS spectra more distinguishable. More importantly, the prepared WO3−x SERS chip through micro–nano printing realizes the separation and detection of multicomponents simultaneously. [ABSTRACT FROM AUTHOR]

Glutathione serves as a common biomarkers in tumor diagnosis and treatment. The levels of its intracellular concentration permit detailed investigation of the tumor microenvironment. However, low polarization and weak Raman scattering cross-section make direct and indirect Raman detection challenging. This study designs an amorphous-crystalline urchin-like TiO 2 (AC-UL-TiO 2 ) for the accurate identification of GSH and GSSG. By synergistically regulating the crystalline core and amorphous shell, the bandgap structure is optimized, thereby enhancing charge transfer efficiency. AC-UL-TiO 2 demonstrates excellent SERS performance in detecting dye molecules with good selectivity for mixed analytes. The enhancement factor (EF) for R6G is 6.89 × 10 6 , and the limit of detection (LOD) is 10 -10  M. A SERS-colorimetric dual-modality platform is developed based on the AC-UL-TiO 2 @DTNB system to accurately monitor GSH concentrations from 0 to 1000 µM, providing a robust dual-confirmation result. Importantly, combined with the principal component analysis method, the AC-UL-TiO 2 SERS platform can directly distinguish GSH and GSSG molecules. Besides, direct SERS detection LOD for GSH and GSSG are 10 -8  M, which is 100 times higher than that of indirect detection. These findings indicate that AC-UL-TiO 2 holds potential for biomarkers trace detection in tumor microenvironments., (© 2025 Wiley‐VCH GmbH.)

As a two-dimensional carbon allotrope, graphdiyne possesses a direct band gap, excellent charge carrier mobility, and uniformly distributed pores. Here, a surfactant-free growth method is developed to efficiently synthesize graphdiyne hollow microspheres at liquid‒liquid interfaces with a self-supporting structure, which avoids the influence of surfactants on product properties. We demonstrate that pristine graphdiyne hollow microspheres, without any additional functionalization, show a strong surface-enhanced Raman scattering effect with an enhancement factor of 3.7 × 10 7 and a detection limit of 1 × 10 -12 M for rhodamine 6 G, which is approximately 1000 times that of graphene. Experimental measurements and first-principles density functional theory simulations confirm the hypothesis that the surface-enhanced Raman scattering activity can be attributed to an efficiency interfacial charge transfer within the graphdiyne-molecule system., (© 2023. Springer Nature Limited.)

Surface-enhanced Raman scattering (SERS) is regarded as the most direct and powerful tool to identify chemical fingerprints. However, current SERS substrate materials still face some critical challenges, including low molecular utilization efficiency and low selectivity. Herein, a novel oxygen vacancy heteropolyacid─H 10 Fe 3 Mo 21 O 51 (HFMO)─is developed as a high-performance volume-enhanced Raman scattering (VERS)-active platform. Due to its merit of water solubility, HFMO forms a special coordination bond with the probe molecule at the molecular level, which allows its enhancing ability to be comparable to that of noble metals. An enhancement factor of 1.26 × 10 9 and a very low detection limit of 10 -13 M for rhodamine 6G were obtained. A robust O-N coordination bond was formed between the anion of HFMO and the probe molecule, resulting in a special electron transfer path (Mo-O-N) with high selectivity, which is verified using X-ray photoelectron spectroscopy analysis and density functional theory calculations. That is to say, the proposed HFMO platform has excellent VERS enhancing effect, specifically for the molecules containing the imino group (e.g., methyl blue, detection limit: 10 -11 M), offering the merits of high reproducibility and uniformity, high-temperature resistance, long-time laser irradiation, and strong acid resistance. Such an initial effort on the ionic type VERS platform may enable the further development of highly sensitive, highly selective, and water-soluble VERS technology.

Due to the intrinsic layered structure, graphdiyne (GDY) strongly tends to form 2D materials, therefore, most of the current research are based on GDY 2D structures. Up to now, the synthesis of its ultrathin nanowires with a high aspect ratio has not been reported. Here, the ultrathin GDY nanowires with diameters below 3 nm are reported for the first time by a two-phase interface synthesis method, which has excellent crystallinity and an aspect ratio of more than 2500. Evidence shows that the GDY ultrathin nanowires are formed by the oriented-attachment mechanism of nanoparticles. The GDY ultrathin nanowires exhibit a significant quantum confinement effect, enhanced photoelectric effect, and promising applications in surface-enhanced Raman sensing., (© 2023 Wiley-VCH GmbH.)

Controlling the structure of graphdiyne (GDY) is crucial for the discovery of new properties and the development of new applications. Herein, the microemulsion synthesis of GDY hollow spheres (HSs) and multiwalled nanotubes composed of ultrathin nanosheets is reported for the first time. The formation of an oil-in-water (O/W) microemulsion is found to be a key factor controlling the growth of GDY. These GDY HSs have fully exposed surfaces because of the avoidance of overlapping between nanosheets, thereby showing an ultrahigh specific surface area of 1246 m 2 g -1 and potential applications in the fields of water purification and Raman sensing.

Polymeric carbon nitride (pCN) has attracted increasing interest as a metal-free photocatalyst because of its high efficiency in reactive oxygen species (ROS) generation. However, due to poor solubility, compounding pCN at the molecular level into more advanced nanocomposites remains a challenge. Herein, we report the dissolution of pCN in polyphosphoric acid (PPA) for the first time and fluid-phase assembly with carbon nanotubes (CNTs) into a flexible free-standing membrane. Mechanism and generality studies disclosed that the coordination of the acidity, viscosity, and adsorption energy of the solvents led to the successful dissolution of pCN. Interestingly, the pCN/CNTs molecular composite membrane exhibited not only superior mechanical properties and cycling performance as a result of strengthened π-π interfacial interaction, but also outstanding inactivation of E. coli and S. aureus in sterilization and wound healing for laboratory mice via photogenerated oxygen radicals. It would open a new era of pCN for biomedical applications in molecular composite membranes, beyond the traditional solar fuel applications in powders., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The construction of open hot-spot structures that facilitate the entry of analytes is crucial for surface-enhanced Raman spectroscopy. Here, metallic niobium nitride (NbN) three-dimensional (3D) hierarchical networks with open nanocavity structure are first found to exhibit a strong visible-light localized surface plasmon resonance (LSPR) effect and extraordinary surface-enhanced Raman scattering (SERS) performance. The unique nanocavity structure allows easy entry of molecules, promoting the utilization of electromagnetic hot spots. The NbN substrate has a lowest detection limit of 1.0 × 10 -12 M and a Raman enhancement factor (EF) of 1.4 × 10 8 for contaminants. Furthermore, the NbN hierarchical networks possess outstanding environmental durability, high signal reproducibility, and detection universality. The remarkable SERS sensitivity of the NbN substrate can be attributed to the joint effect of LSPR and interfacial charge transport (CT).

It is of great significance for practical applications to directly convert readily available biomass carbon into three-dimensional (3D) porous carbon microspheres with a self-supporting structure. Herein, we report the convenient conversion of biomass carbon microspheres to hierarchical porous carbon microspheres (HP-CMSs) with a robust self-supporting framework structure. A general SiO 2 -induced etching mechanism is proposed for the formation of the HP-CMSs. Benefiting from this robust 3D self-supporting frame structure, these HP-CMSs have outstanding mechanical, chemical, and thermal stability. As a metal-free surface-enhanced Raman scattering (SERS) substrate with an ultrahigh specific surface area (4216 m 2 g -1 ) and a high density of active sites, the HP-CMSs exhibit high sensitivity with a detection limit of 10 -10 M and a Raman enhancement factor of 3.5 × 10 6 . By integrating the enrichment and sensing functions of the HP-CMSs in a microfluidic channel, online high-throughput SERS detection of 20 samples within 5 min is achieved in a single channel, and the relative standard deviation of the signals between samples is only 5.1%. The current work develops a convenient preparation method that converts sustainable biomass carbon to 3D hierarchical porous carbon and provides a potential material for sensing, energy, catalysis, and other fields.

Colorimetric sensors have been widely used for centuries across diverse fields, thanks to their easy operation and uncompromisingly high sensitivity with no need for electricity. However, it is still a great challenge for conventional chromogenic systems to perform multiple measurements meanwhile maintaining high robustness. Here, we reported that carbon nitrides (CNs), the raw materials that are abundant, structure-tunable, and stable semiconductors with photoelectron storage capability, can be developed as a chromogenic system for colorimetric sensors. Beyond conventional metal oxides that only demonstrated a single blue-color switch after photoelectron storage, CN exhibited a multicolor switch under identical conditions owing to the unusual multiple photoelectron storage pathways. Mechanism studies revealed cyano and carbonyl groups in CN crucially elongated the centroid distance of electrons/holes, which exclusively stabilized the specific excited states that have different light absorption; meanwhile, the counter cations strengthened these processes. As a result, O 2 , a proof-of-concept analyte, was quantitatively detected by the CN-derived colorimetric sensor, showing high reversibility in hundreds of cycles and adaptable sensitivity/detection range, outperforming most reported and commercial oxygen sensors. These intriguing features of CN are highly envisioned for the next generation of colorimetric sensors, especially in developing countries or fieldworks, to improve the detection reliability and lower the sensing cost.

It is a major challenge to synthesize crystalline transition-metal nitride (TMN) ultrathin nanocrystals due to their harsh reaction conditions. Herein, we report that highly crystalline tungsten nitride (W 2 N, WN, W 3 N 4 , W 2 N 3 ) nanocrystals with small size and excellent dispersibility are prepared by a mild and general in situ surface restraint-induced growth method. These ultrafine tungsten nitride nanocrystals are immobilized in ultrathin carbon layers, forming an interesting hybrid nanobelt structure. The hybrid WN/C nanobelts exhibit a strong localized surface plasmon resonance (LSPR) effect and surface-enhanced Raman scattering (SERS) effect, including a lowest detection limit of 1 × 10 -12 M and a Raman enhancement factor of 6.5 × 10 8 comparable to noble metals, which may be one of the best records for non-noble metal SERS substrates. Moreover, they even can maintain the SERS performance in a variety of harsh environments, showing outstanding corrosion resistance, radiation resistance, and oxidation resistance, which is not available on traditional noble metal and semiconductor SERS substrates. A synergistic Raman enhancement mechanism of LSPR and interface charge transfer is found in the carbon-coated tungsten nitride substrate. A microfluidic SERS channel integrating the enrichment and detection of trace substances is constructed with the WN/C nanobelt, which realizes high-throughput dynamic SERS analysis.

In surface-enhanced Raman spectroscopy (SERS) detection, the structure of the Raman-scattering substrate is critical to the sensitivity and stability of the detector. Herein, molybdenum nitride (MoN) porous structures with a well-defined hexagonal prism shape were synthesized via a precursor nitriding route. As a typical metallic transition-metal nitride (TMN), these molybdenum nitride porous hexagonal prisms exhibit a rare strong SPR effect in the visible region, with a resonance peak centered at 534 nm. Benefiting from the strong SPR effect and their huge surface area and porosity, these MoN porous hexagonal prisms exhibit surface-enhanced Raman scattering effects comparable to those of noble metals, with a Raman enhancement factor of 5.5 × 10 6 . More importantly, these MoN SERS substrates exhibit ultrahigh chemical stabilities that noble metal and semiconductor substrates do not possess, which can prevent corrosion by strong acids, alkalis, and high-temperature oxidation.

The development of online surface-enhanced Raman spectroscopy (SERS) detection methods is crucial to achieving high-throughput efficiency. Herein, a non-noble-metal moving substrate that integrates the functions of enrichment and sensing is developed for the microfluidic online-high-throughput detection of pollutants. The lowest limit of detection of 1 × 10 -12 M and a Raman enhancement factor of 6.3 × 10 8 are obtained on the nanospheres. In a single detection channel, the analysis of 20 samples is achieved within 5 min, and the relative standard deviation of the signals is less than 6.8%. Compared with static SERS detection of fixed substrates, this dynamic SERS detection method greatly reduces the contamination memory effect of the analyte residue, enabling it to perform the sequential quantitative detection of samples with large concentration differences. Moreover, the current online SERS platform realizes the rapid quantitative detection of multicomponent samples.

Looking for high-performance substrates is an important goal of current surface enhanced Raman scattering (SERS) research. Herein, ultrathin multilayer rhenium (Re) nanosheets as a rare-earth metal substrate are found to have extraordinary SERS performance. These Re nanosheets are prepared through a convenient low-temperature molten salt strategy, and their total thickness is ∼5 nm, including 3-4 layers of ultrathin nanosheets with a thickness of only ∼1 nm. The viscosity of molten salt plays a key role in the formation of these ultrathin layered nanosheets. These nanosheets exhibit a strong and well-defined localized surface plasmon resonance (SPR) effect in the visible light region. The plasmonic Re nanosheets show excellent SERS performance with high sensitivity, chemical stability, and signal repeatability. The lowest detection limit for toxic compounds is 10 -12 mol, and the corresponding Raman enhancement factor is 9.1 × 10 8 . A composite enhancement mechanism caused by localized-SPR and charge transport has played an important role in the rare-earth-SERS. High-throughput multiassay analysis is performed on the flexible membrane assembled from the Re nanosheets, which highlights that our system is capable of rapid separation and identification of the samples containing various analytes.

The synthesis of metallic transition metal nitrides (TMNs) has traditionally been performed under harsh conditions, which makes it difficult to prepare TMNs with high surface area and porosity due to the grain sintering. Herein, we report a general and rapid (30 s) microwave synthesis method for preparing TMNs with high specific surface area (122.6-141.7 m 2 g -1 ) and porosity (0.29-0.34 cm 3 g -1 ). Novel single-crystal porous WN, Mo 2 N, and V 2 N are first prepared by this method, which exhibits strong surface plasmon resonance, photothermal conversion, and surface-enhanced Raman scattering effects. Different from the conventional low-temperature microwave absorbing media such as water and polymers, as new concept absorbing media, hydrated metal oxides and metallic metal oxides are found to have a remarkable high-temperature microwave heating effect and play key roles in the formation of TMNs. The current research results provide a new-concept microwave method for preparing high lattice energy compounds with high specific surface.

The development of low-cost, biocompatible, and durable high-performance substrates is an urgent issue in the field of surface-enhanced Raman scattering (SERS). Herein, by reducing and exfoliating the TiO 2 -layered nanoplates in the gas phase, nitrogen-doped titanium monoxide (N-TiO) ultrathin nanosheets composed of 2-3 single layers with a thickness of only ∼1.2 nm are synthesized. Compared with pure TiO, the oxidation resistance of N-TiO is greatly improved, in which the oxidation threshold is significantly increased from 187.5 to 415.6 °C. The N-TiO ultrathin nanosheets are found to have strong surface plasmon resonance in the visible region. These ultrathin N-TiO nanosheets can be easily assembled into a large-scale flexible membrane and exhibit remarkable SERS effects. Moreover, this low-cost flexible SERS substrate combines the high durability of noble-metal substrates and the high biocompatibility of semiconductor substrates.

Facing the complex environment of on-site detection, the development of active substrates with wide-spectrum surface-enhanced Raman scattering (SERS) activity is essential. Herein, we report on the low temperature and reproducible synthesis of plasmonic δ-MoN yolk microspheres by in situ-nitriding amorphous MoO 2 microspheres at 500 °C and 1 atm. The yolk-structured δ-MoN exhibits strong and wide-spectrum surface plasmon resonance and SERS effects and can perform highly selective detection for probes with different absorption wavelengths under excitation of 532, 633, and 785 nm lasers, with a limitation of 10 -11 M and an enhanced factor of 3.6 × 10 7 . Moreover, the plasmonic δ-MoN yolk microspheres have high environmental durability, which can maintain high sensitivity in strong acid and alkaline solutions.

γ-Mo 2 N and δ-MoN are the two most important molybdenum nitrides, but controllable preparation of them with high surface area has not been achieved. Herein, we achieved selective preparation of γ-Mo 2 N and δ-MoN. The key factor for the selective preparation of γ-Mo 2 N and δ-MoN is to control the crystal phase of the precursor MoO 3 . In H 2 O and NH 3 mixed gas, the α-MoO 3 nanoribbons are nitridated to obtain γ-Mo 2 N single-crystal porous nanobelts, while the h-MoO 3 prisms are nitrided to obtain δ-MoN hierarchical porous columns. The corrosion effect of H 2 O plays a key role in the formation of single-crystal porous structure. The γ-Mo 2 N flexible membrane composed of the single-crystal porous nanobelts exhibits strong localized surface plasmon resonance and surface enhanced Raman scattering effect, which show highly sensitive response to polychlorinated phenol.

Structure and size control are always considered to be effective routes to enhance the sensitivity of materials. Herein, rough VO2 (D) nanostars and nanospheres with highly dense and rough surfaces were synthesized. Accompanied by the properties inherited from the rough VO2 nanospheres, i.e., high adsorption and strong plasma resonance, these VO2 (D) nanospheres exhibit highly sensitive activity as a surface enhanced Raman spectrum substrate. The detection limit of Rhodamine 6G on this semiconductor SERS substrate is as low as 10-9 M.

Transition metal nitrides have been widely studied due to their high electrical conductivity and excellent chemical stability. However, their preparation traditionally requires harsh conditions because of the ultrahigh activation energy barrier they need to cross in nucleation. Herein, we report three-dimensional porous VN, MoN, WN, and TiN with high surface area and porosity that are prepared by a general and mild molten-salt route. Trace water is found to be a key factor for the formation of these porous transition metal nitrides. The porous transition metal nitrides show hydrophobic surface and can adsorb a series of organic compounds with high capacity. Among them, the porous VN shows strong surface plasmon resonance, high conductivity, and a remarkable photothermal conversion efficiency. As a new type of corrosion- and radiation-resistant surface-enhanced Raman scattering substrate, the porous VN exhibits an ultrasensitive detection limit of 10 -11  M for polychlorophenol.

Although mesocrystals with ordered building units have great potential in many fields because of the large amount of organic molecules used as structure-directing agents during their synthesis process, severe matrix interference makes their surface-enhanced Raman scattering (SERS) properties rarely understood. Herein, a rapid (20 s) and green microwave synthetic route is developed for the 100 g scale preparation of plasmonic W 18 O 49 mesocrystals with no additives. The ultrathin (1.5 nm) and oxygen vacancy-rich W 18 O 49 nanowires as a building unit greatly improve the interface charge transfer, while the periodic mesocrystal structure significantly enhances the localized surface plasmon resonance effect and creates high-density electromagnetic hot spots among the nanowires. An outstanding enhancement factor of 1.2 × 10 7 and an ultralow detectable limit of 10 -11 M are achieved, and the single-molecule imaging is also realized on this mesocrystal-based SERS substrate. Moreover, the relative standard deviation of the fabricated large-area (2.2 cm 2 ) SERS substrate is only 6.8%.

MoN and Mo 2 C are important functional materials; however, due to the high activation energy barrier in their nucleation, their synthesis generally requires harsh conditions such as high temperature (>1000 °C) and high pressure (several GPa). The extreme conditions also hinder the acquisition of their ultrafine nanostructures. Herein, we report that MoN and Mo 2 C hollow spheres with large surface area (108.7-125.6 m 2 g -1 ) and ultrafine nanoparticles (2-5 nm) are prepared by a quasi-metal-based microwave route under mild conditions. MoO 2 hollow spheres are used as a quasi-metallic microwave absorbing medium as well as a molybdenum source and template simultaneously. The MoN and Mo 2 C ultrafine nanocrystalline hollow spheres exhibit strong localized surface plasmon resonance, high photothermal conversion efficiency, and strong surface-enhanced Raman scattering effects. Highly crystalline MoS 2 nanosheet hollow spheres can also be obtained by this method, indicating its universality. The present work provides an effective strategy for the rapid and mild preparation of ultrafine nanocrystalline transition metal nitrides and carbides with ultrahigh activation energy.

Molybdenum nitride (δ-MoN) is an important functional material due to its impressive catalytic, energy storage, and superconducting properties. However, the synthesis of δ-MoN usually requires extremely harsh conditions; thus, the insight into δ-MoN is far behind that of oxides and sulfides of molybdenum. Herein, we report that ultrathin δ-MoN nanosheets are prepared at 270 °C and 12 atm. WN, VN, and TiN nanosheets are also synthesized by this method. The δ-MoN nanosheets show strong surface plasmon resonance, high conductivity, excellent thermal and chemical stability as well as a high photothermal conversion efficiency of 61.1%. As a promising surface enhanced Raman scattering substrate, the δ-MoN nanosheets exhibit a 8.16 × 10 6 enhanced factor and a 10 -10 level detection limit for polychlorophenol.

In this paper, the gas-sensing properties of copper oxide porous nanosheets in amorphous and highly crystalline states were comparatively investigated on the premise of almost the same specific surface area, morphology and size. Unexpectedly, the results show that amorphous copper oxide porous nanosheets have much better gas sensing properties than highly crystalline copper oxide to a serious of volatile organic compounds, and the lowest detection limit (LOD) of the amorphous copper oxide porous nanosheets to methanal is even up to 10 ppb. By contrast, the LOD of the highly crystalline copper oxide porous nanosheets to methanal is 95 ppb. Experiments prove that the oxygen vacancies contained in the amorphous copper oxide porous nanosheets play a key role in improving gas sensitivity, which greatly improve the chemical activity of the materials, especially for the adsorption of molecules containing oxygen-groups such as methanal and oxygen., (©2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

γ-Ti 3 O 5 is one kind of prominent non-stoichiometric metal oxide due to its intriguing ability in electric and electrochemical behaviors. This work reports another attractive property of γ-Ti 3 O 5 hierarchical porous microspheres, the extremely effective photothermal property with a high photothermal conversion efficiency. Theory and experimental results indicate that γ-Ti 3 O 5 hierarchical porous microspheres possess metallic features and display very strong localized surface plasma resonance effects over the visible and near-infrared region. Under simulated sunlight or near infrared light, the metallic γ-Ti 3 O 5 exhibits a photothermal conversion efficiency of up to 65.29%. Under irradiation by a near-infrared laser with a wavelength of 808 nm, the γ-Ti 3 O 5 hierarchical porous microspheres can significantly inhibit cancer cell viability in vitro and disrupt tumor tissue growth in vivo in a short period. In vitro and in vivo toxicity experiments demonstrate that it has good biocompatibility. The ultrahigh photothermal conversion efficiency and biocompatibility make the γ-Ti 3 O 5 very attractive for technological uses in photothermal therapy, solar energy utilization, and infrared light detection and so on., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Compared with the noble-metal surface-enhanced Raman scattering (SERS) substrates activated by the surface plasmon resonance (SPR)-induced electromagnetic mechanism (EM), the relative low sensitivity and stability of the chemical mechanism (CM)-based substrates are the biggest obstacles to their applications. Herein, we report that quasi-metallic VO 2 nanosheet arrays can be used as a sensitive and stable SERS substrate. The lowest detectable limit of analyte adsorbed on the VO 2 nanosheets achieves 10 -10 M and the maximum Raman enhancement factor (EF) reaches 6.7 × 10 7 , which is comparable with that of the noble metals. The experimental and theoretical results demonstrate that the SERS performance of the VO 2 nanosheets comes from the strong interfacial interactions based on charge transfer and the vigorous SPR effects. Our research results demonstrate that quasi-metals are very promising SERS detection platforms and reveal that CM, like EM, contributes significantly to the SERS activity of quasi-metals., (Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.)

Structure and size control are always considered as effective routes to enhance sensitive performance. Different from common polycrystalline porous nanosheets, herein, the general synthesis of monocrystalline ultrathin porous nanosheets (MUPNSs) by a facile decompressing decomposition (DPD) route is reported. Accompanied with the properties inherited from MUPNSs, i.e., high adsorption and strong plasma resonance, these MoO2 MUPNSs presented high sensitive activity as a surface enhanced Raman spectrum (SERS) substrate. The SERS sensitivity of MoO2 MUPNSs was about 1000 times higher than MoO2 polycrystalline ultrathin porous nanosheets (PUPNSs).

Compared with noble metals, improving the sensitivity of semiconducting surface-enhanced Raman scattering (SERS) substrates is of great significance to their fundamental research and practical application of Raman spectroscopy. In this paper, it is found that the SERS sensitivity is increased by 10 000 times by reducing the semiconducting TiO 2 microspheres to quasi-metallic Ti 3 O 5 microspheres. Its lowest detectable limit is up to 10 -10 M, which may be the best among the non-noble metal substrates and even reaches or exceeds certain Au/Ag nanostructures to the best of our knowledge. This new type of non-noble metal SERS substrate breaks through the bottleneck of poor stability of conventional semiconductor substrate and can withstand high temperature oxidation at 200 °C and strong acid-base corrosion without performance degradation. Benefiting from its excellent ability of visible-light photocatalytic degradation of organic molecules, the substrate can be reused. Moreover, the new material also exhibits excellent photothermal conversion properties.

We demonstrate for the first time that metallic carbide nanoparticles with a strong localized surface plasmon resonance (LSPR) effect could be used as SERS substrates to detect trace substances. They achieve a noble metal-comparable enhancement factor of 6.4 × 107.

The photothermal effect of dextran coated Fe 3 O 4 nanoparticles for cancer therapy is investigated in this work. The dextran/Fe 3 O 4 nanoparticles were prepared by coprecipitation method. Results demonstrated that the dextran not only isolated the interior Fe 3 O 4 nanoparticles from oxygen and water to enhance the photothermal stability, but also enhanced the biocompatibility of Fe 3 O 4 nanoparticles. In vitro experiments indicated that dextran/Fe 3 O 4 nanoparticles showed low toxicity to cells without any irradation. After near-infrared (NIR) laser irradiation, however, the viabilities of tumor cells were effectively suppressed. Further in vivo experimental studies found that mice tumor growth was significantly inhibited by the photothermal effect of dextran/Fe 3 O 4 nanoparticles. After 28 days the tumor was completely cleared. These dextran/Fe 3 O 4 nanoparticles have biosecurity and high photothermal efficiency at the same time, thus promising high clinical potential., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Increasing the sensitivity of non-noble metal surface-enhanced Raman spectroscopy (SERS) is an urgent issue that needs to be solved at present. Herein, metallic W 18 O 49 nanowires with a strong localized surface plasmon resonance (LSPR) effect are prepared. Interestingly, the LSPR peaks of these nanowires would undergo a strong blue shift from near-infrared (NIR) to visible light regions as the aggregation degree of the nanowires increases. By narrowing the gap between the LSPR absorption peak and the Raman excitation wavelength (532 nm), the oriented W 18 O 49 bundles with a LSPR peak centered at 561 nm have greatly improved SERS sensitivity compared with that of the dispersed nanowires with a LSPR peak centered at 1025 nm. Enhancement mechanism investigation shows that the high sensitivity can be attributed to the synergistic effect of LSPR coupling among the oriented ultrathin nanowires and oxygen vacancy (V o )-assisted charge transfer.

Photothermal therapy (PTT) is one of promising cancer therapy with high efficiency and minimal invasiveness. Exploiting of perfect PTT agent is vital to improve the therapy. In this study, a new type of bow tie-like molybdenum dioxide (MoO 2 ) nanoparticles was successfully synthesized. These nanobow-ties had strong localized surface plasmon resonance (SPR) effect from visible to near infrared regions, and exhibited ultrahigh chemical stability. They could not only withstand high temperature heating without oxidation, but also resist the corrosion of strong acid and alkali. Meanwhile, the MoO 2 nanoparticles were highly stable in protein-containing biological medium, though they partly degraded in PBS solution. Both in vivo and in vitro experiments indicated that they exhibited inappreciable toxicity. Under illumination of near infrared laser, they showed excellent PTT effect, as revealed by significant inhibition of cancer cell viability in vitro and efficient destruction in tumor tissue growth in vivo. These MoO 2 nanoparticles possessed highly chemical stability and low toxicity with high PTT efficiency, thus promising them high potential as nanoagent in cancer treatment., (Copyright © 2018. Published by Elsevier Ltd.)

Rapid, on-site analysis was achieved through significantly simplified operation procedures for a wide variety of toy samples (crayon, temporary tattoo sticker, finger paint, modeling clay, and bubble solution) using a miniature mass spectrometry system with ambient ionization capability. The labor-intensive analytical protocols involving sample workup and chemical separation, traditionally required for MS-based analysis, were replaced by direct sampling analysis using ambient ionization methods. A Mini β ion trap miniature mass spectrometer was coupled with versatile ambient ionization methods, e.g. paper spray, extraction spray and slug-flow microextraction nanoESI for direct identification of prohibited colorants, carcinogenic primary aromatic amines, allergenic fragrances, preservatives and plasticizers from raw toy samples. The use of paper substrates coated with Co 3 O 4 nanoparticles allowed a great increase in sensitivity for paper spray. Limits of detection as low as 5μgkg -1 were obtained for target analytes. The methods being developed based on the integration of ambient ionization with miniature mass spectrometer represent alternatives to current in-lab MS analysis operation, and would enable fast, outside-the-lab screening of toy products to ensure children's safety and health., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Semiconductor-based surface-enhanced Raman spectroscopy is getting more and more attention because of its great price advantage. One of the biggest obstacles to the large-scale application of it is the poor stability. Here, we report that plasmonic MoO 2 nanospheres can be used as a highly sensitive and stable semiconducting-substrate material for surface-enhanced Raman scattering (SERS). By using the MoO 2 nanospheres as Raman substrates, a series of typical compounds with high attention can be accurately detected. This new non-noble metal substrate material shows a very high detection limit of 10 -8 M, and exhibits great near-field enhancement with one of the highest enhancement factor of 4.8 × 10 6 reported to date. More importantly, the oxide with intermediate valence displays unexpected ultrahigh stability, which can withstand the corrosion of strong acid and strong alkali as well as 150 °C high temperature oxidation in air. Moreover, the accurate detection of multicomponent samples was also successful on this substrate. These results show that some simple metal oxides with intermediate valence may become sensitive and stable SERS substrate materials due to their abundant free electrons and structure that easily causes hot spots.

Compared with noble metals, semiconductors with surface plasmon resonance effect are another type of SERS substrate materials. The main obstacles so far are that the semiconducting materials are often unstable and easy to be further oxidized or decomposed by laser irradiating or contacting with corrosive substances. Here, we report that metallic MoO 2 can be used as a SERS substrate to detect trace amounts of highly risk chemicals including bisphenol A (BPA), dichloropheno (DCP), pentachlorophenol (PCP) and so on. The minimum detectable concentration was 10 -7  M and the maximum enhancement factor is up to 3.75 × 10 6 . To the best of our knowledge, it may be the best among the metal oxides and even reaches or approaches to Au/Ag. The MoO 2 shows an unexpected high oxidation resistance, which can even withstand 300 °C in air without further oxidation. The MoO 2 material also can resist long etching of strong acid and alkali.

We report a general route for the direct growth of metal particles on TiO2 nanosheets with (001) exposed facets by an oxygen-vacancy-driven self-redox reaction. As there is no need for thermal treatment to remove stabilizing agents, the structure of the nanoparticles can be retained, preserving the active sites associated with high activity., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A facile solvothermal epitaxial growth combined with a mild oxidation route has been developed for the fabrication of a magnetically recyclable Fe(3)O(4)/WO(3) core-shell visible-light photocatalyst. In this core-shell structured photocatalyst, visible-light-active WO(3) nanoplates (the shells) with high surface area are used as a medium to harvest absorbed photons and convert them to photogenerated charges, while conductive Fe(3)O(4) microspheres (the cores) are used as charge collectors to transport the photogenerated charges. This is a new role for magnetite. The Fe(3)O(4)/WO(3) core-shell structured photocatalysts possess large surface-exposure area, high visible-light-absorption efficiency, stable recyclability, and efficient charge-separation properties, the combination of which has rarely been reported in other visible-light-active photocatalysts. Photoelectrochemical investigations verify that the core-shell structured Fe(3)O(4)/WO(3) has a more effective photoconversion capability than pure WO(3) or Fe(3)O(4). At the same time, the visible-light photocatalytic ability of the Fe(3)O(4)/WO(3) photocatalyst has significantly enhanced activity in the photodegradation of organic-dye materials. The results presented herein provide new insights into core-shell materials as high-performance visible-light photocatalysts and their potential use in environmental protection., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A hierarchical macro-/mesoporous Ce(0.49)Zr(0.37)Bi(0.14)O(1.93) solid-solution network has been synthesized on a large scale by means of a simple and general polymerization-carbonization-oxidation synthetic route. The as-prepared product has been characterized by SEM, XRD, TEM, BET surface area measurement, UV/Vis diffuse-reflectance spectroscopy, energy-dispersive X-ray spectroscopy (EDS), and photoelectrochemistry measurements. The photocatalytic activity of the product has been demonstrated through the photocatalytic degradation of methyl orange. Structural characterization has indicated that the hierarchical macro-/mesoporous solid-solution network not only contains numerous macropores, but also possesses an interior mesoporous structure. The mesopore size and BET surface area of the network have been measured as 2-25 nm and 140.5 m(2) g(-1), respectively. The hierarchical macro-/mesoporous solid-solution network with open and accessible pores was found to be well-preserved after calcination at 800 degrees C, indicating especially high thermal stability. Due to its high specific surface area, the synergistic effect of the coupling of macropores and mesopores, and its high crystallinity, the Ce(0.49)Zr(0.37)Bi(0.14)O(1.93) solid-solution material shows a strong structure-induced enhancement of visible-light harvest and exhibits significantly improved visible-light photocatalytic activity in the photodegradation of methyl orange compared with those of its other forms, such as mesoporous hollow spheres and bulk particles.