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Chilling causes a significant decline in photosynthesis in tomato plants. Tomato tryptophan decarboxylase gene 1 (SlTDC1) is the first rate-limiting gene for melatonin (MT) biosynthesis and is involved in the regulation of photosynthesis under various abiotic stresses. However, it is not clear whether SlTDC1 participates in the photosynthesis of tomato under chilling stress. Here, we obtained SlTDC1 overexpression transgenic tomato seedlings, which showed higher SlTDC1 mRNA abundance and MT content compared with the wild type (WT). The results showed that the overexpression of SlTDC1 obviously alleviated the chilling damage to seedlings in terms of the lower electrolyte leakage rate and hydrogen peroxide content, compared with the WT after 2 d of chilling stress. Moreover, the overexpression of SlTDC1 notably increased photosynthesis under chilling stress, which was related to the higher chlorophyll content, normal chloroplast structure, and higher mRNA abundance and protein level of Rubisco and RCA, as well as the higher carbon metabolic capacity, compared to the WT. In addition, we found that SlTDC1-overexpressing seedlings showed higher Wk (damage degree of OEC on the PSII donor side), φEo (quantum yield for electron transport in the PSII reaction center), and PIABS (photosynthetic performance index) than WT seedlings after low-temperature stress, implying that the overexpression of SlTDC1 decreased the damage to the reaction center and donor-side and receptor-side electron transport of PSII and promoted PSI activity, as well as energy absorption and distribution, to relieve the photoinhibition induced by chilling stress. Our results support the notion that SlTDC1 plays a vital role in the regulation of photosynthesis under chilling stress.

Due to the great potential of surface-enhanced Raman scattering (SERS) as local vibrational probe of lipid-nanostructure interaction in lipid bilayers, it is important to characterize these interactions in detail. The interpretation of SERS data of lipids in living cells requires an understanding of how the molecules interact with gold nanostructures and how intermolecular interactions influence the proximity and contact between lipids and nanoparticles. Ceramide, a sphingolipid that acts as important structural component and regulator of biological function, therefore of interest to probing, lacks a phosphocholine head group that is common to many lipids used in liposome models. SERS spectra of liposomes of a mixture of ceramide, phosphatidic acid, and phosphatidylcholine, as well as of pure ceramide and of the phospholipid mixture are reported. Distinct groups of SERS spectra represent varied contributions of the choline, sphingosine, and phosphate head groups and the structures of the acyl chains. Spectral bands related to the state of order of the membrane and moreover to the amide function of the sphingosine head groups indicate that the gold nanoparticles interact with molecules involved in different intermolecular relations. While cryogenic electron microscopy shows the formation of bilayer liposomes in all preparations, pure ceramide was found to also form supramolecular, concentric stacked and densely packed lamellar, nonliposomal structures. That the formation of such supramolecular assemblies supports the intermolecular interactions of ceramide is indicated by the SERS data. The unique spectral features that are assigned to the ceramide-containing lipid model systems here enable an identification of these molecules in biological systems and allow us to obtain information on their structure and interaction by SERS.

Immune-oncology therapies targeting adaptive immunity have transformed cancer therapy. In contrast, therapies targeting the innate immune response have received less attention. Here we describe an antibody drug conjugate (ADC) capable of engaging neutrophils in targeted cell killing. These initial ADCs, which we term bactabodies, consist of a targeting antibody conjugated to formyl-Met peptides via a short polyethylene glycol linker to activate formyl peptide receptor-1 (FPR-1) on neutrophils. A trastuzumab (Tmab) bactabody stimulated human neutrophil migration, degranulation and reactive oxygen production. Her2+ tumor cells opsonized with Tmab bactabody were rapidly killed by primary human neutrophils and antibody targeted killing was more effective than FPR-1-mediated bystander killing. In vivo, Tmab bactabody activated intratumor neutrophils and reduced tumor growth in a mouse xenotransplant model. Molecular design elements required for translation to humans and mice are described. Our results establish a modular strategy for engineering novel ADCs to engage neutrophils in targeted cell killing.

With an improved charge separation efficiency, the heterojunction catalysts are widely used to enhance photocatalytic activity. However, the transfer mechanism of photoexcited charge carriers remains unclear and the researches about...

Grafting is widely applied to enhance the tolerance of some vegetables to biotic and abiotic stress. Salicylic acid (SA) is known to be involved in grafting-induced chilling tolerance in cucumber. Here, we revealed that grafting with pumpkin (Cucurbita moschata, Cm) as a rootstock improved chilling tolerance and increased the accumulation of SA, abscisic acid (ABA) and hydrogen peroxide (H2O2) in grafted cucumber (Cucumis sativus/Cucurbita moschata, Cs/Cm) leaves. Exogenous SA improved the chilling tolerance and increased the accumulation of ABA and H2O2 and the mRNA abundances of CBF1, COR47, NCED, and RBOH1. However, 2-aminoindan-2-phosphonic acid (AIP) and L-a-aminooxy-b-phenylpropionic acid (AOPP) (biosynthesis inhibitors of SA) reduced grafting-induced chilling tolerance, as well as the synthesis of ABA and H2O2, in cucumber leaves. ABA significantly increased endogenous H2O2 production and the resistance to chilling stress, as proven by the lower electrolyte leakage (EL) and chilling injury index (CI). However, application of the ABA biosynthesis inhibitors sodium tungstate (Na2WO4) and fluridone (Flu) abolished grafting or SA-induced H2O2 accumulation and chilling tolerance. SA-induced plant response to chilling stress was also eliminated by N,N′-dimethylthiourea (DMTU, an H2O2 scavenger). In addition, ABA-induced chilling tolerance was attenuated by DMTU and diphenyleneiodonium (DPI, an H2O2 inhibitor) chloride, but AIP and AOPP had little effect on the ABA-induced mitigation of chilling stress. Na2WO4 and Flu diminished grafting- or SA-induced H2O2 biosynthesis, but DMTU and DPI did not affect ABA production induced by SA under chilling stress. These results suggest that SA participated in grafting-induced chilling tolerance by stimulating the biosynthesis of ABA and H2O2. H2O2, as a downstream signaler of ABA, mediates SA-induced chilling tolerance in grafted cucumber plants.

Monolayer-ordered gold nanoring arrays were prepared by ion-sputtering method and used as surface enhanced Raman spectroscopy (SERS) substrates to test the individual atmospheric aerosols particle. Compared to other methods used for testing atmospheric aerosols particles, the collection and subsequent detection in our work is performed directly on the gold nanoring SERS substrate without any treatment of the analyte. The SERS performance can be tuned by changing the depth of the gold nanoring cavity as originating from coupling of dipolar modes at the inner and outer surfaces of the nanorings. The electric field exhibits uniform enhancement and polarization in the ordered Au nanoring substrate, which can improve the accuracy for detecting atmospheric aerosol particles. Combined with Raman mapping, the information about chemical composition of individual atmospheric aerosols particle and distribution of specific components can be presented visually. The results show the potential of SERS in enabling improved analysis of aerosol particle chemical composition, mixing state, and other related physicochemical properties.

Water-soluble organic carbon (WSOC), which is closely related to biogenic emissions, is of great importance in the atmosphere for its ubiquitous existence and rich abundance. Levoglucosan, a typical WSOC, is usually considered to be stable and thus used as a tracer of biomass burning. However, we found that levoglucosan can be photo-oxidized on mineral dust, with formic acid, oxalic acid, glyoxylic acid, 2,3-dioxopropanoic acid, dicarbonic acid, performic acid, mesoxalaldehyde, 2-hydroxymalonaldehyde, carbonic formic anhydride, and 1,3-dioxolane-2,4-dione detected as main products. Further, we observed the heterogeneous uptake of NH3 promoted by the carboxylic acids stemming from the photocatalytic oxidation (PCO) of levoglucosan. The mineral-dust-initiated PCO of levoglucosan and enhanced heterogeneous uptake of NH3, which are highly influenced by irradiation and moisture conditions, were for the first time revealed. The reaction mechanisms and pathways were studied in detail by diffuse reflection infrared Fourier transform spectroscopy (DRIFTS), high-pressure photon ionization time-of-flight mass spectrometry (HPPI-ToF-MS) and flow reactor systems. Diverse WSOC constituents were studied as well, and the reactivity toward NH3 is related to the number of hydroxyl groups of the WSOC molecules. This work reveals a new precursor of secondary organic aerosols and provides experimental evidence of the existence of organic ammonium salts in atmospheric particles.

Objective. The objective is to explore the surgical index, postoperative complications, recovery speed, and prognosis of Stanford type A aortic dissection (AD) compared with traditional ’Sun’s operation. Methods. One hundred patients with Stanford type A AD treated from February 2018 to February 2021 were enrolled in our hospital. Patients were randomly divided into control and research group. The former group underwent traditional Sun’s surgery, and the latter group underwent combined debranching surgery. The general data, surgical indexes, total amount of blood transfusion, renal function 72 hours after operation, postoperative indexes during hospitalization, and follow-up results after discharge were compared between the two groups. Results. The CPB time, ACC time, operation time, and postoperative total drainage volume of the study group were all lower than those of the control group, and the intraoperative urine volume of the study group was higher than that of the control group ( P < 0.05 ). The total amount of RBC infused in the study group was higher than that in the control group, while the total amount of PLT, cryoprecipitate, and plasma infusion in the study group was lower than that in the control group ( P < 0.05 ). At 72 hours after operation, BUN, Scr, and UA in the study group were significantly lower than those in the control group ( P < 0.05 ). The number of the secondary intubation, hemodialysis, neurological complications, and deaths in the study group was significantly lower than that in the control group ( P < 0.05 ). Conclusion. Both Sun’s operation and branch removal are more effective treatment methods, and the two different surgical methods have different indications, advantages, and disadvantages, so different surgical methods can be chosen according to different conditions for Stanford AD. The possible postoperative complications should be comprehensively analyzed in the clinical work in order to reduce the occurrence of postoperative complications and improve the cure rate.

Among the possible products of CO2 electrochemical reduction, CO plays a unique and vital role, which can be an ideal feedstock for further reduction to C2+ products, and also the important component of syngas that can be used as feedstock for value-added chemicals and fuels. However, it is still a challenge to tune the CO selectivity on Cu electrode. Here we newly construct an ultrasound-assisted electrochemical method for CO2 reduction, which can tune the selectivity of CO2 to CO from less than 10% to greater than 80% at -1.18 V versus (vs.) reversible hydrogen electrode (RHE). The partial current density of CO production is significantly improved by 15 times. By in-situ Raman study, the dominating factor for the improved CO production is attributed to the accelerated desorption of *CO intermediate. This work provides a facile method to tune the product selectivity in CO2 electrochemical reduction.

Detecting atmospheric bioaerosols in a quantitative way is highly desirable for public health and safety. This work demonstrates that surface-enhanced Raman spectroscopy (SERS) is a simple and rapid analytical technique for the detection of atmospheric bioaerosols, on a Klarite substrate. For both simulated and ambient bioaerosols, this detection assay results in an increase in the enhancement factor of the Raman signal. We report a strong SERS signal generated by bioaerosols containing living Escherichia coli deposited on Klarite. Furthermore, we demonstrate that SERS mapping can be used to estimate the percentage of airborne, living Escherichia coli. Moreover, Klarite provides differently distinct SERS spectra at different bacterial growth phases, indicating its potential to identify changes occurring in the bacterial envelope. Finally, we applied SERS for the rapid detection of Escherichia coli in ambient bioaerosols without using time-consuming and laborious culture processes. Our results represent rapid, culture-free and label-free detection of airborne bacteria in the real-world environment.

Although still poorly understood, electrolytes can play a key role in obtaining the desired product from the electrochemical reduction of CO2. To address this issue, it is of great significance to better understand the relationship between the selectivity and the activity of the reaction and the electrode structure and the electrolyte. Herein, the influence of electrolytes, especially those that contain halide ions, on the CO2 reduction performance was studied using Cu-based electrodes with various surface components, including Cu0, Cu+ and a mixed state of Cu0, Cu+ and Cu2+. The results show that Cl− and Br− improved the CH4 selectivity for all tested Cu-based electrodes, while the effect of I− was very sensitive to the surface state of Cu. On the one hand, I− could corrode Cu2O and form CuI, which could stabilize Cu+, resulting in a higher faradaic efficiency for C2H4. On the other hand, I− had a negative effect on C2H4 selectivity in the presence of Cu0 and Cu2+. When Cu+ was present on the electrode surface, the ratio of C2H4/CH4 was significantly changed from 19.3 (in KHCO3 electrolyte) to 372.1 (in KHCO3 + KI electrolyte). Our findings improve the understanding of the cooperation between the catalyst and halide electrolytes to produce the desired product and, in particular, the C2 product.

It is still poorly understood how the first intermediates of CO2 reduction are formed and converted to multi-carbon products over Cu-based electrodes. Herein, Ag is used to decorate dendritic Cu and a high Faradaic efficiency (FE) for C2 H4 (25 %) is obtained on a CuAg electrode, which is about five times higher than dendritic Cu. The intermediates including *CO2 - , OH groups, Cu-CO, C-O rotation, and CHx species are investigated by in situ Raman spectroscopy. This work provides spectroscopic evidence that the first intermediate of CO2 reduction on Ag-decorated Cu is carboxylate anion *CO2 - bonded with the catalyst surface through the C and O atom. The formation and evolution process of the *CO2 - intermediate over the applied potential are investigated in depth as well. This research contributes to a better understanding of the mechanism of CO2 reduction and multi-carbon product formation pathways over Ag-decorated Cu.

Surface enhanced Raman spectroscopy (SERS) shows great promise in studying individual atmospheric aerosol. However, the lack of efficient, stable, uniform, large-array, and low-cost SERS substrates constitutes a major roadblock. Herein, a new SERS substrate is proposed for detecting individual atmospheric aerosol particles. It is based on the sphere segment void (SSV) structure of copper and silver (Cu/Ag) alloy. The SSV structure is prepared by an electrodeposition method and presents a uniform distribution, over large 2 cm 2 arrays and at low cost. The substrate offers a high SERS enhancement factor (due to Ag) combined with lasting stability (due to Cu). The SSV structure of the arrays generates a high density of SERS hotspots (1.3 × 10 14/cm 2), making it an excellent substrate for atmospheric aerosol detection. For stimulated sulfate aerosols, the Raman signal is greatly enhanced (>50 times), an order of magnitude more than previously reported substrates for the same purpose. For ambient particles, collected and studied on a heavy haze day, the enhanced Raman signal allows ready observation of morphology and identification of chemical components, such as nitrates and sulfates. This work provides an efficient strategy for developing SERS substrate for detecting individual atmospheric aerosol.

Salicylic acid (SA) has been proven to be a multifunctional signaling molecule that participates in the response of plants to abiotic stresses. In this study, we used cold-sensitive cucumber and cold-tolerant pumpkin as experimental materials to examine the roles of SA in root–shoot communication responses to aerial or/and root-zone chilling stress in own-root and hetero-root grafted cucumber and pumpkin plants. The results showed that pumpkin (Cm) rootstock enhanced the chilling tolerance of grafted cucumber, as evidenced by the observed lower levels of electrolyte leakage (EL), malondialdehyde (MDA), and higher photosynthetic rate (Pn) and gene expression of Rubisco activase (RCA). However, cucumber (Cs) rootstock decreased the chilling tolerance of grafted pumpkins. Cs/Cm plants showed an increase in the mRNA expression of C-repeat-binding factor (CBF1), an inducer of CBF expression (ICE1), and cold-responsive (COR47) genes and CBF1 protein levels in leaves under 5/25 and 5/5°C stresses, or in roots under 25/5 and 5/5°C stresses, respectively, compared with the Cs/Cs. Chilling stress increased the endogenous SA content and the activity of phenylalanine ammonia-lyase (PAL), and the increase in SA content and activity of PAL in Cs/Cm plants was much higher than in Cs/Cs plants. Transcription profiling analysis revealed the key genes of SA biosynthesis, PAL, ICS, and SABP2 were upregulated, while SAMT, the key gene of SA degradation, was downregulated in Cs/Cm leaves, compared with Cs/Cs leaves under chilling stress. The accumulation of SA in the Cs/Cm leaves was mainly attributed to an increase in SA biosynthesis in leaves and that in transport from roots under aerial and root-zone chilling stress, respectively. In addition, exogenous SA significantly upregulated the expression level of cold-responsive (COR) genes, enhanced actual photochemical efficiency (ΦPSII), maximum photochemical efficiency (Fv/Fm), and Pn, while decreased EL, MDA, and CI in grafted cucumber. These results suggest that SA is involved in rootstock–scion communication and grafting-induced chilling tolerance by upregulating the expression of COR genes in cucumber plants under chilling stress.

Melatonin (MT) and nitric oxide (NO) are two multifunctional signaling molecules that are involved in the response of plants to abiotic stresses. However, how MT and NO synergize in response to cold stress affecting plants is still not clear. In this study, we found that endogenous MT accumulation under cold stress was positively correlated with cold tolerance in different varieties of cucumber seedlings. The data presented here also provide evidence that endogenous NO is involved in the response to cold stress. About 100 μM MT significantly increased the nitrate reductase (NR) activity,NR-relative messenger RNA (mRNA) expression, and endogenous NO accumulation in cucumber seedlings. However, 75 μM sodium nitroprusside (SNP, a NO donor) showed no significant effect on the relative mRNA expression of tryptophan decarboxylase (TDC), tryptamine-5-hydroxylase (T5H), serotonin-N-acetyltransferase (SNAT), or acetylserotonin O-methyltransferase (ASMT), the key genes for MT synthesis and endogenous MT levels. Compared with H2O treatment, both MT and SNP decreased electrolyte leakage (EL), malondialdehyde (MDA), and reactive oxygen species (ROS) accumulation by activating the antioxidant system and consequently mitigated cold damage in cucumber seedlings. MT and SNP also enhanced photosynthetic carbon assimilation, which was mainly attributed to an increase in the activity and mRNA expression of the key enzymes in the Calvin–Benson cycle. Simultaneously, MT- and SNP-induced photoprotection for both photosystem II (PSII) and photosystem I (PSI) in cucumber seedlings, by stimulating the PsbA (D1) protein repair pathway and ferredoxin-mediated NADP+photoreduction, respectively. Moreover, exogenous MT and SNP markedly upregulated the expression of chilling response genes, such as inducer ofCBFexpression (ICE1), C-repeat-binding factor (CBF1), and cold-responsive (COR47). MT-induced cold tolerance was suppressed by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO, a specific scavenger of NO). However, p-chlorophenylalanine (p-CPA, a MT synthesis inhibitor) did not affect NO-induced cold tolerance. Thus, novel results suggest that NO acts as a downstream signal in the MT-induced plant tolerance to cold stress.

Micro- and nanoplastics are considered one of the top pollutants that threaten the environment, aquatic life and mammalian (including human) health. Unfortunately, the development of uncomplicated but reliable analytical methods that are sensitive to individual microplastic particles, with sizes smaller than 1 μm, remains incomplete. Here, we demonstrate the detection and identification of (single) micro- and nanoplastics, by using surface-enhanced Raman spectroscopy (SERS), with Klarite substrates. Klarite is an exceptional SERS substrate; it is shaped as a dense grid of inverted pyramidal cavities, made of gold. Numerical simulations demonstrate that these cavities (or pits) strongly focus incident light into intense hotspots. We show that Klarite has the potential to facilitate the detection and identification of synthesized and atmospheric/aquatic microplastic (single) particles, with sizes down to 360 nm. We find enhancement factors of up to two orders of magnitude for polystyrene analytes. In addition, we detect and identify microplastics with sizes down to 450 nm on Klarite, with samples extracted from ambient, airborne particles. Moreover, we demonstrate Raman mapping as a fast detection technique for sub-micron microplastic particles. The results show that SERS with Klarite is a facile technique that has the potential to detect and systematically measure nanoplastics in the environment. This research is an important step towards detecting nanoscale plastic particles that may cause toxic effects to mammalian and aquatic life when present in high concentrations.

Graphical abstract Ultrasound significantly accelerate the desorption of *CO resulting in high CO selectivity., Among the possible products of CO2 electrochemical reduction, CO plays a unique and vital role, which can be an ideal feedstock for further reduction to C2+ products, and also the important component of syngas that can be used as feedstock for value-added chemicals and fuels. However, it is still a challenge to tune the CO selectivity on Cu electrode. Here we newly construct an ultrasound-assisted electrochemical method for CO2 reduction, which can tune the selectivity of CO2 to CO from less than 10% to >80% at −1.18 V versus (vs.) reversible hydrogen electrode (RHE). The partial current density of CO production is significantly improved by 15 times. By in-situ Raman study, the dominating factor for the improved CO production is attributed to the accelerated desorption of *CO intermediate. This work provides a facile method to tune the product selectivity in CO2 electrochemical reduction.

Summary Recently, the environmental impacts of microplastics have received extensive attention owing to their accumulation in the environment. However, developing efficient technology for the control and purification of microplastics is still a big challenge. Herein, we investigated the photocatalytic degradation of typical microplastics such as polystyrene (PS) microspheres and polyethylene (PE) over TiO2 nanoparticle films under UV light irradiation. TiO2 nanoparticle film made with Triton X-100 showed complete mineralization (98.40%) of 400-nm PS in 12 h, while degradation for varying sizes of PS was also studied. PE degradation experiment presented a high photodegradation rate after 36 h. CO2 was found as the main end product. The degradation mechanism and intermediates were studied by in situ DRIFTS and HPPI-TOFMS, showing the generation of hydroxyl, carbonyl, and carbon-hydrogen groups during the photodegradation of PS. This study provides a green and cost-efficient strategy for the control of microplastics contamination in the environment., Graphical Abstract, Highlights • Efficient degradation of microplastics under UV light by TiO2 film • Triton-based TiO2 film showed higher photocatalytic performance • The role of radical species during microplastics degradation was elucidated • Degradation mechanism and reaction intermediates were explored, Catalysis; Environmental Chemistry; Nanomaterials

A mispronunciation detection and diagnosis (MD&D) system typically consists of multiple stages, such as an acoustic model, a language model and a Viterbi decoder. In order to integrate these stages, we propose SED-MDD, an end-to-end model for sentence dependent mispronunciation detection and diagnosis (MD&D) . Our proposed model takes mel-spectrogram and characters as inputs and outputs the corresponding phone sequence. Our experiments prove that SED-MDD can implicitly learn the phonological rules in both acoustic and linguistic features directly from the phonological annotation and transcription in the training data. To the best of our knowledge, SED-MDD is the first model of its kind and it achieves an accuracy of 86.35% and a correctness of 88.61% on L2-ARCTIC which significantly outperforms the existing end-to-end mispronunciation detection and diagnosis (MD&D) model CNN-RNN-CTC.

SO2 and CO2 emitted from using of fossil fuels are causing serious environmental issues. Herein we put forward a promising strategy to realize CO2 reduction and SO2 removal simultaneously through a photoelectrochemical (PEC) process based on nanoelectrodes. In the present work, SO2 was oxidized to SO42− on BiVO4 photoanode after being absorbed by NaHCO3 solutions. At the same time, CO2 reduction occurred on nanoflower-like copper-indium alloy cathode. The absorption efficiency of SO2 was greater than 95%, and SO32− was oxidized to SO42− with oxidation efficiency about 50% in 3 h. Moreover, the energy of SO2 was recycled to assist the CO2 reduction on the cathode, consequently, the photocurrent densities were increased at least 3 times after introducing SO2. CO2 reduction with CO and HCOOH as main products was improved significantly when SO2 removal was conducted simultaneously. In-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments were also performed to study the adsorption and conversion of SO2 on BiVO4 nanoparticles. The proposed approach could efficiently remove SO2 and recycle the energy of it to reduce CO2 into useful chemicals. This work provides a sustainable strategy for dealing with CO2 and SO2 in the flue gas by combining desulfurization and CO2 reduction in one PEC cell using nanoelectrodes.

Sulfite is recently found to be promising in enhancing photocatalytic pollutants degradation, and it is a byproduct from flue gas desulfuration process. Herein, 4-chlorophenol (4-CP) photodegradation was systematically investigated in a sulfite mediated system with g-C3N4 as photocatalyst. The degradation efficacy was improved by about 3 times with addition of 25 mM Na2SO3. The dominant responsible reactive oxygen species for chlorophenols remediation in the presence of sulfite included O2·-, SO3·-, and SO4·- as confirmed by radical quenching experiments and electron spin resonances technology. In-situ DRIFTs results indicated the improved cleavage of C-Cl and C-H bonds with the simultaneous formation of C O and C C bonds when bisulfite was added. Degradation intermediates such as 4-chlorocatechol, hydroquinone, and muconic acid were detected by HPLC-MS. Furthermore, the photodegradation mechanisms were discussed in the presence of sulfite. Other chlorophenols (phenol, 2-CP, 2,4-DCP, and their mixture) were also efficiently removed in the system, suggesting that sulfite could be universally applied in photocatalytic wastewater purification.

Microdroplets present unique physiochemical properties, which can influence chemical reactions and atmospheric aerosol processes. The microdroplets’ pH is one of the most important factors that dictate chemical processes, such as heterogeneous and condensed reactions. However, currently, there is no well-established method for directly measuring the pH in microdroplets. Herein, we develop a straightforward method, for the first time, to directly measure the pH of size-resolved, micron-sized single droplets with Surface Enhanced Raman Scattering (SERS)-activated pH-indicator paper; realized by embedded Au nanoparticles (20, 40 and 60 nm). We establish the key parameters for optimizing the method, and demonstrate its accuracy by benchmarking various acids and solutions with different ionic strength. With the established method, we report the pH dependence on the size of microdroplets. Microdroplets of sizes down to 230 nm can be analyzed by our method. We also showcase our method’s applicability to ambient samples, establishing its promising potential beyond the laboratory environment.

Converting solar energy into valuable hydrogen and hydrocarbon fuels through photoelectrocatalytic water splitting and CO2 reduction is highly promising in addressing the growing demand for renewable and clean energy resources. However, the solar-to-fuel conversion efficiency is still very low due to limited light absorption and rapid bulk recombination of charge carriers. In this work, we present chlorophyll (Chl) and its derivative sodium copper chlorophyllin (ChlCuNa), as dye sensitizers, modified BiVO4 to improve the photoelectrochemical (PEC) performance. The photocurrent of BiVO4 is surprisingly decreased after a direct sensitization of Chl while the sensitization of ChlCuNa obviously enhances photocurrent of BiVO4 electrodes by improved surface hydrophilicity and extended light absorption. ChlCuNa-sensitized BiVO4 achieves an improved H2 evolution rate of 5.43 μmol h−1 cm−2 in water splitting and an enhanced HCOOH production rate of 2.15 μmol h−1 cm−2 in CO2 PEC reduction, which are 1.9 times and 2.4 times higher than pristine BiVO4, respectively. It is suggested that the derivative ChlCuNa is a more effective sensitizer for solar-to-fuel energy conversion and CO2 utilization than Chl.

Hexagonal boron nitride (h-BN) is an important member of two-dimensional (2D) materials with a large direct bandgap, and has attracted growing interest in ultraviolet optoelectronics and nanoelectronics. Compared with graphene and graphite, h-BN has weak Raman effect because of the far off-resonance excitation; hence, it is difficult to exploit Raman spectroscopy to characterize important properties of 2D h-BN, such as thickness, doping, and strain effects. Here, we applied stimulated Raman scattering (SRS) to enhance the sensitivity of the E2g Raman mode of h-BN. We showed that SRS microscopy achieves rapid high resolution imaging of h-BN with a pixel dwell time 4 orders of magnitude smaller than conventional spontaneous Raman microscopy. Moreover, the near-perfect linear dependence of signal intensity on h-BN thickness and isotropic polarization dependence allow convenient determination of the flake thickness with SRS imaging. Our results indicated that SRS microscopy provides a promising tool for high-speed quantification of h-BN and holds the potential for vibrational imaging of 2D materials.

It is still poorly understood how the first intermediates of CO

Despite the increased awareness of heterogeneous reaction on mineral dust, the knowledge of how the intensity of solar irradiation influences the photochemistry activity remains a crucially important part in atmospheric research. Relevant studies have not seriously discussed the photochemistry under weak sunlight during haze, and thus ignored some underlying pollution and toxicity. Here, we investigated the heterogeneous formation of nitrate and nitrite under various illumination conditions by laboratory experiments and field observations. Observed by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), water-solvated nitrate was the main surface product, followed by other species varying with illumination condition. The growth of nitrate formation rate tends to be slow after the initial fast with increasing light intensity. For example, the geometric uptake coefficient (γgeo) under 30.5 mW/cm2 (5.72 × 10−6) has exceeded the 50 % of that under 160 mW/cm2 (1.13 × 10−5). This case can be explained by the excess NO2 adsorption under weak illumination while the excess photoinduced active species under strong irradiation. Being negatively associated with nitrate (R2 = 0.748, P