Latest ArticlesThe Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) layered cathodes endow Li-ion batteries (LIBs) with high energy density. However, they usually suffer from limited ion-diffusion and structural instability during cycling. Although doping strategy can effectively alleviate these issues, the coupling effects of multi-element doping and the corresponding performance enhancement mechanism have been yet unclear. Here, we report a Zr/Ti dual-doped NCM811 cathode material (ZT-NCM811), in which Zr-ion is doped into both transition metal (TM) layers and lithium layers and Ti-ion is only distributed in TM layers. The dual-doping can effectively enhance crystal structure stability via inhibiting the lattice collapse along c-axis and decreasing the Li/Ni disorder. Meantime, the lattice oxygen escape is also greatly reduced due to the presence of stronger Zr-O and Ti-O bonds, further mitigating the crystal surface parasitic reactions with electrolyte. The resultant ZT-NCM811 exhibits high specific capacity of 124 mAh/g at even 10 C, much higher than undoped and single-doped NCM811, and a retention of 98.8% at 1 C after 100 cycles. The assembled ZT-NCM811/graphite full cell also delivers superior battery performances and durability.
Various phototheranostics have recently been developed for phototherapy. Through proper molecular design, the photochemical and photophysical properties of these phototheranostics can be promoted. Herein, an acceptor-donor-acceptor (A-D-A)-structured dye, BTP-4F-DMO, was synthesized and prepared into water-soluble nanoparticles (NPs). The obtained BTP-4F-DMO NPs had strong absorption from 650 nm to 850 nm and a fluorescence emission peak at ~900 nm that tailed to ~1100 nm. The NPs showed a superhigh photothermal conversion efficiency of 90.5% ± 5% and could simultaneously generate •OH and 1O2 with a 1O2 generation quantum yield of 4.6% under 808 nm laser irradiation. Due to these advanced properties, BTP-4F-DMO NPs can switch the role of autophagy from pro-survival to pro-death, thereby further promoting cancer cell death. These features make BTP-4F-DMO NPs a promising multifunctional phototheranostic agent for NIR-Ⅱ fluorescence/photoacoustic dual-mode imaging-guided synergetic photodynamic/photothermal therapy. In general, this work provides a strategy for expanding the biomedical applications of organic A-D-A-structured phototheranostics.
Glioma is a malignant primary brain tumor that is extremely harmful to human beings. Therefore, studying the invasiveness of glioma cells is of great significance for the diagnosis and treatment of glioma. In this work, TiO2/Nb2C was prepared as a SERS substrate and combined with microfluidic chip to construct an invasion model capable of monitoring glioma invasion in real time. Both experimental data and density function theory (DFT) calculations showed that the significant SERS-enhancing effect of TiO2/Nb2C on methylene blue (MB) originated from the chemical magnification (CM) mechanism when MB was used as the adsorbed molecule. Based on this, we achieved a highly sensitive and targeted detection of vascular endothelial growth factor (VEGF), a biomarker for glioma with a low detection limit of 3.7 pg/mL, then quantified the invasive process in real time by detecting VEGF. Meanwhile, the depletion of reactive oxygen species (ROS) by TiO2/Nb2C can inhibit the invasion of glioma cells. For the first time, the invasion model combines SERS technology with microfluidic technology, while monitoring the cell invasion process in real time, the invasion process can be quantified by detecting the VEGF secreted by glioma cells during the invasion process, realizing the integration of diagnosis and treatment, and establish a new model for the biomedical analysis, clinical diagnosis and treatment of glioma.
Due to the serious imbalance between demand and supply of lithium, lithium extraction from brine has become a research hotspot. With the demand for power lithium-ion batteries (LIBs) increased rapidly, a large number of spent LiFePO4 power batteries have been scrapped and entered the recycling stage. Herein, a novel and efficient strategy is proposed to extract lithium from brine by directly reusing spent LiFePO4 powder without any treatment. Various electrochemical test results show that spent LiFePO4 electrode has appropriate lithium capacity (14.62 mgLi/gLiFePO4), excellent separation performance (αLi-Na = 210.5) and low energy consumption (0.768 Wh/gLi) in electrochemical lithium extraction from simulated brine. This work not only provides a novel idea for lithium extraction from brine, but also develops an effective strategy for recycling spent LIBs. The concept of from waste to wealth is of great significance to the development of recycling the spent batteries.
Diketopyrrolopyrrole (DPP) and related derivatives have drawn great attention due to their applications in organic optical /electronic materials. Progress in these materials is associated with developments in the syntheses of the DPP family. Chemical modification of DPP at nitrogen atom, including N-alkylation and N-arylation, is an effective strategy to improve its physical and chemical properties, such as solubility, optical and semiconducting properties. However, N-arylation of DPPs remains challenging compared to the easily accessible N-alkylation. Herein, the synthesis of N-aryl DPP derivatives and correlated π-expanded DPPs are summarized, and their optical/electronic properties are introduced. The future perspectives of N-aryl DPP derivatives are also discussed.
Atomically precise metal nanoclusters (NCs) have been deemed as an emerging class of metal nanomaterials owing to fascinating size-dependent physicochemical properties, discrete energy band structure, and quantum confinement effect, which are distinct from conventional metal nanoparticles (NPs). Nevertheless, metal NCs suffer from photoinduced self-oxidative aggregation accompanied by in-situ transformation to metal NPs, markedly reducing the photosensitization of metal NCs. Herein, maneuvering the generic instability of metal NCs, we perform the charge transport impetus comparison between atomically precise metal NCs and plasmonic metal NPs counterpart obtained from in-situ self-transformation of metal NCs in photoelectrochemical (PEC) water splitting reaction. For conceptual demonstration, we proposed two quintessential heterostructures, which include TNTAs-Au25 heterostructure fabricated by electrostatically depositing glutathione (GSH)-protected Au25(GSH)18 NCs on the TiO2 nanotube arrays (TNTAs) substrate, and TNTAs-Au heterostructure constructed by triggering self-transformation of Au25(GSH)18 NCs to plasmonic Au NPs in TNTAs-Au25 via calcination. The results indicate that photoelectrons produced over Au25 NCs are superior to hot electrons of plasmonic Au NPs in stimulating the interracial charge transport toward solar water oxidation. This is mainly ascribed to the significantly accelerated carrier transport kinetics, prolonged carrier lifespan, and substantial photosensitization effect of Au25 NCs compared with plasmonic Au NPs, resulting in the considerably enhanced PEC water splitting performance of TNTAs-Au25 relative to plasmonic TNTAs-Au counterpart under visible light irradiation. Our work would provide important implications for rationally designing atomically precise metal NCs-based photosystems toward solar energy conversion.
Over the last 50 years, the explosive adoption of modern agricultural practices has led to an enormous increase in the emission of non-biodegradable and highly biotoxic ions into the hydrosphere. Excess intake of such ions, even essential trace elements such as Cu2+ and F−, can have serious consequences on human health. Therefore, to ensure safe drinking water and regulate wastewater discharge, photoelectrochemical (PEC) online sensors were developed, with advantages such as low energy consumption, inherent miniaturization, simple instrumentation, and fast response. However, there is no publicly available systematic review of the recent advances in PEC ion sensors available in the literature since January 2017. Thus, this review covers the various strategies that have been used to enhance the sensitivity, selectivity, and limit of detection for PEC ion sensors. The photoelectrochemically active materials, conductive substrates, electronic transfer, and performance of various PEC sensors are discussed in detail and divided into sections based on the measurement principle and detected ion species. We conclude this review by highlighting the challenges and potential future avenues of research associated with the development of novel high-performance PEC sensors.
The application of metal-organic frameworks (MOFs) nanozymes in biosensing has been extensively investigated, however, till now there is still no report on photoelectrochemical (PEC) sensing based on enzyme memetic properties of MOFs. To further expand the utilization of MOFs nanozymes in biosensing, we developed a label-free homogenous PEC aptasensor for the detection of VEGF165, an important cancer biomarker, based on the DNA-regulated peroxidase-mimetic activity of Fe-MIL-88, a type of MOFs. In this strategy, the peroxidase-mimetic property of MOFs is integrated with the label-free homogeneous PEC sensing approach, and highly sensitive detection of VEGF165 is obtained with a detection limit down to 33 fg/mL, superior or comparable to the previously reported values. Moreover, this approach displays outstanding specificity, and has been successfully used to detect VEGF165 added in diluted serum samples. As far as we know, it is the first example to employ the peroxidase-like activity of MOFs in PEC biosensing, which may find potential application in bioanalysis and early disease diagnosis.
Nitrate (NO3−) is widely found in wastewater, which is harmful to human health and water environmental. Electrochemical reduction can convert NO3− to high value-added ammonia (NH3)/ammonium (NH4+) for pollutant removal and resource recovery. Currently, electrochemical nitrate reduction to produce ammonia (ENRA) is mostly focused on the preparation of high-performance catalysts, while ignoring the prerequisite for industrial application as the stable operation and optimal regulation of the process. Therefore, the review focused on wastewater treatment, based on the mechanism of electrochemical nitrate reduction for ammonia production and reactor construction (reactor, power supply system), then summarized the operation control strategies (such as reduction potential, nitrate concentration, inorganic ions, pH) that should be noted for ENRA. Finally, the challenges (system structure, economy) and prospects (ammonia recovery process, construction of large-scale ENRA system, application of real wastewater) of the field as it moves towards commercialization were discussed. It is hoped that this review will facilitate the scaling up of ENRA in the wastewater treatment field.
DNAzyme amplifiers have been extensively explored as a useful sensing platform, but single DNAzyme amplifier is limited in biosensing applications by its low sensitivity. Herein, a cascade DNAzyme amplifier was designed by exploiting concurrent amplification cycle principles of toehold-mediated strand displacement reaction (TSDR) and Zn2+-assisted DNAzyme cycle with lower cost and simpler procedures. Compared with single DNAzyme amplifier, the proposed TSDR-propelled cascade DNAzyme amplifier exhibited higher sensitivity by releasing more DNAzyme through TSDR to cleave substrate strand during the DNAzyme cycle. Base on this, let-7a could be sensitively detected in the range of 5–50 nmol/L with a detection limit of 64 pmol/L. Furthermore, the dual signal amplification strategy of the cascade DNAzyme amplifier exhibited excellent selectivity to distinguish single-base mismatched DNA strands, which has been successfully applied to the determination of let-7a in blood serum, showing high promise in early cancer diagnosis.