Maximizing the Potential of Electrically Conductive MOFs.

ConspectusElectrically conductive metal-organic frameworks (EC-MOFs) have emerged as a compelling class of materials, drawing increasing attention due to their unique properties facilitating charge transport within porous structures. The synergy between electrical conductivity and porosity has opened a wide range of applications, including electrocatalysis, energy storage, chemiresistive sensing, and electronic devices that have been underexplored for their insulating counterparts. Despite these promising prospects, a prevalent challenge arises from the predominant adoption of two-dimensional (2D) structures by most EC-MOFs. These 2D frameworks often show modest surface areas and short interlayer distances, hindering molecular accessibility, which deviates from the inherent characteristics of conventional MOFs. Furthermore, the quest for efficient charge transport imposes design constraints, leading to a restricted selection of functional building blocks. Additionally, there is a lack of established functionalization methods within EC-MOFs, limiting their functional diversity. Thus, these challenges have impeded EC-MOFs from reaching their full potential.In this Account, we summarize and discuss our group's efforts aimed at enhancing molecular accessibility and deploying the functional diversity of EC-MOFs. Our focus on enhancing molecular accessibility involves several strategies. First, we employed macrocyclic ligands with intrinsic pockets as the building blocks for EC-MOFs. The integrated intrinsic pockets in the frameworks supplement surface areas and additional pores to enhance molecular accessibility. The resulting macrocyclic ligand-based EC-MOFs exhibit exceptionally high surface areas and confer advantages in electrochemical performances. Second, our efforts extend to addressing the structural limitations, frequently associated with EC-MOFs' 2D structures. Through the pillar insertion strategy, we transformed a 2D EC-MOF platform into a three-dimensional (3D) structure, thereby achieving higher porosity and enhanced molecular accessibility. In pursuing functional diversity, we have delved into molecular-level tuning of EC-MOF building blocks. We demonstrated that electron-rich alkyne-based pockets in the macrocyclic ligands can host transition metals and alkali ions, enabling ion selectivity and showcasing diverse use of EC-MOFs. We utilized a postsynthetic approach to further functionalize metal nodes on the molecular level within an EC-MOF framework, introducing a proton-conducting pathway while preserving its electrical conductivity.We aspire for this Account to provide practical insights and strategies to surmount structural and functional diversity limitations in the realm of EC-MOFs. By integrating enhanced molecular accessibility and diverse functionality, our endeavor to propel the utility of these materials will inspire further rational development for future EC-MOFs and unlock their full potential.

Photocatalytic Hydrogen Peroxide Production through Functionalized Semiconductive Metal-Organic Frameworks.

Hydrogen peroxide (H2O2) holds significance as a vital chemical with the potential to serve as an energy carrier. Compared with the conventional anthraquinone process, photocatalytic H2O2 production has emerged as an appealing alternative because of its energy efficiency and environmental sustainability. However, the existing photocatalysts suffer from low catalytic efficiency, limited tunability of optical properties, and reliance on sacrificial agents due to high energy loss caused by inefficient charge separation. Therefore, developing catalysts with tunable optical properties and efficient charge separation is desirable. In this work, we introduce postsynthetic functionalization into an electrically conductive metal-organic framework, namely, DPT-MOF. Leveraging DPT (3,6-di(4-pyridyl)-1,2,4,5-tetrazine) as a pillar ligand, we exploited click-type chemistry to manipulate band position and charge separation efficiency, allowing for photocatalytic nonsacrificial H2O2 production. Notably, the fluorine-functionalized MOF exhibited the highest H2O2 production rate of 1676 µmol g-1 h-1 under visible light in O2-saturated water among our other samples. This high production rate is attributed to the tuned electronic structure and prolonged charge lifetime facilitated by the fluorine groups. This work highlights the effectiveness of postsynthetic methodology in tuning optical properties, opening a promising avenue for advancing the field of semiconductive MOF-based photocatalysis.

Exposure to bisphenol A and fiber-type microplastics induce oxidative stress and cell damage in disk abalone Haliotis discus hannai: Bioaccumulation and toxicity.

Along with environmental pollution caused by rapid economic development and industrialization, plastic waste is emerging as a global concern in relation to marine ecosystems and human health. Among the microplastics, fiber-type microfibers (MF) and bisphenol A (BPA), which are widely used as plasticizers, do not decompose well in the ocean, and tend to accumulate in organisms, generating an increased oxidative stress response. This study investigated the abalones' antioxidant and cell death responses following exposure to the environmental pollutants MF and BPA. Levels of malondialdehyde (MDA) and DNA damage increased over time, demonstrating the degree of lipid peroxidation and DNA damage in abalones exposed to individual and combined environmental conditions of MF and BPA. Compared to the single MF and BPA exposure groups, the combined exposure group showed a higher expression of antioxidant enzymes. A similar pattern was seen in the expression of the apoptosis enzyme caspase-3. Both MF and BPA caused oxidative stress and antioxidant enzymes were expressed to alleviate it, but it is believed that cell damage occurred because the stress level exceeded the allowed range.

Linker-Based Bandgap Tuning in Conductive MOF Solid Solutions.

Herein, the synthesis of Cu3 (HAB)x (TATHB)2-x (HAB: hexaaminobenzene, TATHB: triaminotrihydroxybenzene) is reported. Synthetic improvement of Cu3 (TATHB)2 leads to a more crystalline framework with higher electrical conductivity value than previously reported. The improved crystallinity and analogous structure between TATHB and HAB enable the synthesis of Cu3 (HAB)x (TATHB)2-x with ligand compositions precisely controlled by precursor ratios. The electrical conductivity is tuned from 4.2 × 10-8 to 2.9 × 10-5  S cm-1 by simply increasing the nitrogen content in the crystal lattice. Furthermore, computational calculation supports that the solid solution facilitates the band structure tuning. It is envisioned that the findings not only shed light on the ligand-dependent structure-property relationship but create new prospects in synthesizing multicomponent electrically conductive metal-organic frameworks (MOFs) for tailoring optoelectronic device applications.

Carbazolylene-Ethynylene Macrocycle based Conductive Covalent Organic Frameworks.

Two covalent organic frameworks consisting of carbazolylene-ethynylene shape-persistent macrocycles with azine (MC-COF-1) or imine (MC-COF-2) linkages were synthesized via imine condensation. The obtained 2D frameworks are fully conjugated which imparts semiconducting properties. In addition, the frameworks showed high porosity with aligned accessible porous channels along the z axis, serving as an ideal platform for post-synthetic incorporation of I2 into the channels to enable electrical conductivity. The resulting MC-COF-1 showed an electrical conductivity up to 7.8×10-4  S cm-1 at room temperature upon I2 doping with the activation energy as low as 0.09 eV. Furthermore, we demonstrated that the electrical properties of both MC-COFs are switchable between electron-conducting and insulating states by simply implementing doping-regenerating cycles. The knowledge gained in this study opens new possibilities for the future development of tunable conductive 2D organic materials.

Imparting Functionality and Enhanced Surface Area to a 2D Electrically Conductive MOF via Macrocyclic Linker.

The development of 2D electrically conductive metal-organic frameworks (EC-MOFs) has significantly expanded the scope of MOFs' applications into energy storage, electrocatalysis, and sensors. Despite growing interest in EC-MOFs, they often show low surface area and lack functionality due to the limited ligand motifs available. Herein we present a new EC-MOF using 2,3,8,9,14,15-hexahydroxyltribenzocyclyne (HHTC) linker and Cu nodes, featuring a large surface area. The MOF exhibits an electrical conductivity up to 3.02 × 10-3 S/cm and a surface area up to 1196 m2/g, unprecedentedly high for 2D EC-MOFs. We also demonstrate the utilization of alkyne functionality in the framework by postsynthetically hosting heterometal ions (e.g., Ni2+, Co2+). Additionally, we investigated particle size tunability, facilitating the study of size-property relationships. We believe that these results not only contribute to expanding the library of EC-MOFs but shed light on the new opportunities to explore electronic applications.

Insight into the molecular structure and function of peptidoglycan recognition protein SC2 (PGRP-SC2) from Amphiprion clarkii: Investigating the role in innate immunity.

Peptidoglycan recognition proteins (PGRPs) belong to the pattern recognition receptor (PRR) family and are conserved from insects to mammals. PGRPs show specific binding abilities to peptidoglycans (PGNs) in various microbes. In this study, molecular and functional analyses of PGRP-SC2 from Amphiprion clarkii (AcPGRP-SC2) were conducted. The 492 bp ORF of AcPGRP-SC2 encoded a protein of 164 amino acids with a molecular weight of 17.58 kDa and pI of 8.9. The PGRP superfamily domain was identified from the protein sequence of AcPGRP-SC2 and sequence similarities were observed with homologous proteins. Quantitative polymerase chain reaction (qPCR) analysis revealed that AcPGRP-SC2 transcripts were ubiquitously expressed in all tested tissues, with high levels in the skin, and transcript expression was significantly modulated by immune stimulation with lipopolysaccharide (LPS), Polyinosinic:polycytidylic acid (poly I:C), and Vibrio harveyi post-immune challenge. Recombinant AcPGRP-SC2 with the maltose-binding protein fusion (rAcPGRP-SC2) was used to evaluate LPS-, PGN-, and bacterial-binding activities and to conduct bacterial agglutination assays, and the results demonstrated that AcPGRP-SC2 exhibited bacterial recognition, binding, and colonization abilities to a range of Gram-positive and Gram-negative bacterial strains. Moreover, rAcPGRP-SC2-pre-treated Fat Head Minnow (FHM) cells exhibited significant upregulation in NF-ĸB1, NF-ĸB2, and stat3 expression upon treatment with killed bacteria. Taken together, our findings suggest that AcPGRP-SC2 plays an important role in the immune response against microbial pathogens in A. clarkii.

Gonadotropin-releasing hormone-independent effects of recombinant vertebrate ancient long opsin in the goldfish Carassius auratus reveal alternative reproduction pathways.

Vertebrate ancient long (VAL)-opsin is a green-sensitive photoreceptor that shows high sequence similarity to vertebrate ancient opsin, which is considered to play a role in sexual maturation via gonadotropin-releasing hormone (GnRH); however, the role of VAL-opsin in vertebrate sexual maturity remains unclear. Therefore, we investigated the possible role of VAL-opsin in reproduction in the goldfish Carassius auratus under a state of GnRH inhibition. Goldfish were injected with recombinant VAL-opsin protein (0.5 µg/g body mass) and/or the GnRH antagonist cetrorelix (0.5 µg/fish), and changes in the mRNA expression levels of genes associated with goldfish reproduction were measured by quantitative polymerase chain reaction, including those involved in the hypothalamus-pituitary-gonad (HPG) axis, VAL-opsin, GnRH, the gonadotropins (GTHs) luteinizing hormone and follicle-stimulating hormone, and estrogen receptor (ER). Moreover, the fish were irradiated with a green light-emitting diode (520 nm) to observe the synergistic effect on the HPG axis with VAL-opsin. Green LED exposure significantly and slightly increased the VAL-opsin and GnRH levels, respectively; however, these effects were blocked in groups injected with cetrorelix at all time points. Cetrorelix significantly decreased the mRNA levels of GTHs and ER, whereas these hormones recovered by co-treatment with VAL-opsin. These results indicate that green LED is an effective light source to promote the expression of sex hormones in fish. Moreover, VAL-opsin not only affects activity of the HPG axis but also appears to act on the pituitary gland directly to stimulate a new sexual maturation pathway that promotes the secretion of GTHs independent of GnRH.

Apolipoprotein B binds to enolase-1 and aggravates inflammation in rheumatoid arthritis.

OBJECTIVE: Immune cells from patients with rheumatoid arthritis (RA) express more enolase-1 (ENO1) on their surface than those from healthy subjects, and they elicit an enhanced inflammatory response. This study is aimed to identify the ligands of ENO1 that could promote inflammatory loops in vitro and enhance the arthritis severity in vivo. METHODS: ENO1-binding proteins in RA synovial fluid were identified by mass spectromety, and affinity to ENO1 was evaluated by means of a ligand blotting and binding assay, surface plasmon resonance and confocal microscopy. Proinflammatory response by the interaction between ENO1 and apolipoprotein B (apoB) was tested in vitro and in vivo using peripheral blood mononuclear cells and a K/BxN serum transfer arthritis model and low-density lipoproteins receptor (LDLR) knockout mice. RESULTS: ApoB in the synovid fluid of patients with RA was identified as a specific ligand to ENO1 with a higher affinity than plasminogen, a known ENO1 ligand. ApoB binding to ENO1 on monocytes elicited the production of tumour necrosis factor-α, interleukins (IL)-1ß and IL-6 through both p38 mitogen-activated protein kinase and NF-κB pathways. In the K/BxN serum transfer arthritis model, administration of apoB increased the production of proinflammatory cytokines and exaggerated arthritis severity. The severity of K/BxN serum transfer arthritis in LDLR knockout mice was comparable with wild-type mice. CONCLUSIONS: A key component of atherogenic lipids, apoB, aggravated arthritis by potentiating the inflammatory response via its interaction with ENO1 expressed on the surface of immune cells. This suggests a novel mechanism by which lipid metabolism regulates chronic inflammation in RA.

Engineering Reaction Kinetics by Tailoring the Metal Tips of Metal-Semiconductor Nanodumbbells.

Semiconductor-metal hybrid nanostructures are one of the best model catalysts for understanding photocatalytic hydrogen generation. To investigate the optimal structure of metal cocatalysts, metal-CdSe-metal nanodumbbells were synthesized with three distinct sets of metal tips, Pt-CdSe-Pt, Au-CdSe-Au, and Au-CdSe-Pt. Photoelectrochemical responses and transient absorption spectra showed that the competition between the charge recombination at the metal-CdSe interface and the water reduction on the metal surface is a detrimental factor for the apparent hydrogen evolution rate. For instance, a large recombination rate (krec) at the Pt-CdSe interface limits the quantum yield of hydrogen generation despite a superior water reduction rate (kWR) on the Pt surface. To suppress the recombination process, Pt was selectively deposited onto the Au tips of Au-CdSe-Au nanodumbbells in which the krec was diminished at the Au-CdSe interface, and the large kWR was maintained on the Pt surface. As a result, the optimal structure of the Pt-coated Au-CdSe-Au nanodumbbells reached a quantum yield of 4.84%. These findings successfully demonstrate that the rational design of a metal cocatalyst and metal-semiconductor interface can additionally enhance the catalytic performance of the photochemical hydrogen generation reactions.

Effects of recombinant vertebrate ancient long opsin on reproduction in goldfish, Carassius auratus: profiling green-wavelength light.

This study was conducted to identify the possible effect of recombinant vertebrate ancient long (VAL) opsin as a non-visual "photoreceptor" in the deep brain of goldfish, Carassius auratus. In addition, we investigated the effects of green-wavelength light on the predictable reproductive function of VAL-opsin as a green-sensitive pigment in the deep brain. To determine this, we quantified changes in gonadotropin hormone (GTH) [GTHα, follicle stimulating hormone (FSH) and luteinizing hormone (LH)] and estrogen receptor (ER; ERα and ERß) mRNA expression levels associated with goldfish reproduction as well as changes in plasma FSH, LH, and 17ß-estradiol (E2) activities after injection of recombinant VAL-opsin protein in two concentrations (0.1 or 0.5 µg/g body mass) for 4 weeks (injection once weekly) and examined the possible impact of green-wavelength light (500, 520, and 540 nm) on the function of VAL-opsin. As a result, all parameters associated with reproduction significantly increased with time and light-emitting diode (LED) exposure. Based on these results, we suggested that VAL-opsin in the deep brain is involved in goldfish maturation, and it is possible that green-wavelength light improves the ability of VAL-opsin to promote maturation by increasing VAL-opsin expression.

Effects of light-emitting diode spectra on the vertebrate ancient long opsin and gonadotropin hormone in the goldfish Carassius auratus.

We determined the molecular mechanism underlying the environmental (photoperiodic) regulation of sexual maturation in fish, we examined the expression of sexual maturation-related hormones and vertebrate ancient long opsin (VAL-opsin) in goldfish (Carassius auratus) exposed to different light spectra (red and green light-emitting diodes). We further evaluated the effect of exogenous gonadotropin hormone (GTH) on the expression of VAL-opsin under different light conditions. Our results demonstrated that the expression of GTHs was higher in the fish exposed to green light, and VAL-opsin levels were increased in the fish receiving GTH injection. Therefore, we have uncovered a molecular mechanism underlying the environmental (light)-induced trigger for sexual maturation: VAL-opsin is activated by green light and GTH, which promotes the expression of sexual maturation genes.

Effects of melatonin injection or green-wavelength LED light on the antioxidant system in goldfish (Carassius auratus) during thermal stress.

We tested the mitigating effects of melatonin injections or irradiation from green-wavelength light-emitting diodes (LEDs) on goldfish (Carassius auratus) exposed to thermal stress (high water temperature, 30 °C). The effects of the two treatments were assessed by measuring the expression and activity levels of the antioxidant enzymes, superoxide dismutase and catalase, plasma hydrogen peroxide, lipid hydroperoxide, and lysozyme. In addition, a comet assay was conducted to confirm that high water temperature damaged nuclear DNA. The expression and activity of the antioxidant enzymes, plasma hydrogen peroxide, and lipid hydroperoxide were significantly higher after exposure to high temperature and were significantly lower in fish that received melatonin or LED light than in those that received no mitigating treatment. Plasma lysozyme was significantly lower after exposure to high temperature and was significantly higher after exposure to melatonin or LED light. The comet assay revealed that thermal stress caused a great deal of damage to nuclear DNA; however, treatment with melatonin or green-wavelength LED light prevented a significant portion of this damage from occurring. These results indicate that, although high temperatures induce oxidative stress and reduce immune system strength in goldfish, both melatonin and green-wavelength LED light inhibit oxidative stress and boost the immune system. LED treatment increased the antioxidant and immune system activity more significantly than did melatonin treatment.

Clinical and Genetic Features of Korean Patients with Recurrent Fever and Multi-System Inflammation without Infectious or Autoimmune Evidence.

Autoinflammatory disease (AID) is a newly proposed category of disorders characterized by unprovoked episodes of inflammation without any infectious or autoimmune evidence. We aimed to characterize the clinical and genetic features of patients who had recurrent fever and multi-system inflammation but remain unclassified for any established AIDs. Medical records of 1,777 patients who visited our Rheumatology Clinic between March 2009 and December 2010 were reviewed to identify those who met the following criteria; 1) presence of fever, 2) inflammation in two or more organ systems, 3) recurrent nature of fever or inflammation, 4) no evidence of infection or malignancy, 5) absence of high titer autoantibodies, and 6) failure to satisfy any classification criteria for known AIDs. Genotyping was performed for common missense variants in MEFV, NOD2/CARD15, and TNFRSF1A. A small number of patients (17/1,777, 0.95%) were identified to meet the above criteria. Muco-cutaneous and musculoskeletal features were most common, but there was a considerable heterogeneity in symptom combination. Although they did not satisfy any established classification criteria for AIDs, substantial overlap was observed between the clinical spectrum of these patients and known AIDs. According to the newly proposed Eurofever criteria for periodic fevers, eleven of them were classified as TNF receptor-associated periodic syndrome and two as mevalonate kinase deficiency. However, no examined genetic variants including those in TNFRSF1A were found in these patients. A new set of classification criteria needs to be developed and validated for Asian patients with unclassified AIDs.

Effects of melatonin and green-wavelength LED light on the physiological stress and immunity of goldfish, Carassius auratus, exposed to high water temperature.

This study investigated the effects of increasing water temperature (22-30 °C) on the physiological stress response and immunity of goldfish, Carassius auratus, and the ability of green light-emitting diode (LED) irradiation or melatonin injections to mitigate this temperature-induced stress. To evaluate the effects of either green-wavelength LED light or melatonin on stress in goldfish, we measured plasma triiodothyronine (T3), thyroxine (T4), and thyroid hormone receptor (TR) mRNA expression; plasma cortisol and glucose; and immunoglobulin M (IgM) and lysozyme mRNA expression. The thyroid hormone activities, TR mRNA expression, and plasma cortisol and glucose were higher in goldfish exposed to high-temperature water, but were lower after exposure to melatonin or green-wavelength LED light. Lysozyme mRNA expression and plasma IgM activity and protein expression were lower after exposure to high water temperatures and higher after melatonin or green-wavelength LED light treatments. Therefore, high water temperature induced stress and decreased immunity; however, green-wavelength LED light and melatonin treatments mitigated the effects of stress and enhanced immunity. The benefits of melatonin decreased with time, whereas those of green-wavelength LED treatment did not.

Single nucleotide polymorphisms in IL-10-mediated signalling pathways in Korean patients with Behçet's disease.

OBJECTIVES: Previous genome-wide association studies have demonstrated an association between the IL-10 region and Behçet's disease (BD) in Turkish and Japanese populations. Our aim was to fully examine the relationship between IL-10 and BD, the associations between BD and single nucleotide polymorphisms (SNPs) in IL-10-mediated signalling pathways (JAK1, TYK2, and STAT3) were examined in Korean patients with BD. METHODS: DNA samples were obtained from 223 patients who met the international study group criteria for BD and from 222 age- and sex-matched healthy controls. Twenty-four tag SNPs in JAK1, STAT3, and TYK2 were selected for genotyping based on the Japanese panel of international HapMap data with a minor allele frequency >5% and r2 >0.8. RESULTS: The allele-based analysis showed that the T allele of rs310245 in JAK1 was associated with BD (odds ratio [95% confidence interval] = 1.34 [1.03-1.76], p=0.031), which lost statistical significance after permutation-based correction for multiple testing. In the genotype-based analysis, the JAK1 rs310245 TT homozygote (1.79 [1.14-2.82], p=0.012) and the STAT3 rs2293152 GG homozygote (2.01 [1.16-3.47], p=0.011) showed associations with BD. However, these associations did not achieve significance after correction for multiple testing. We did not observe any genetic interaction between the JAK1 rs310245 TT homozygote and the STAT3 rs2293152 GG homozygote. In the haplotype analysis, GT haplotype at rs17127024 and rs310245 (1.34 [1.03-1.74], p=0.032), and the AA haplotype at rs2256298 and rs3818753 (1.41 [1.03-1.92], p=0.034) in JAK1 were associated with BD, but lost statistical significance after correction for multiple testing. CONCLUSIONS: There was no significant association between BD and SNPs in IL-10-mediated intracellular signalling in Korean patients.

Genome-wide association study identifies GIMAP as a novel susceptibility locus for Behcet's disease.

OBJECTIVES: To identify non-major histocompatibility complex susceptible genes that might contribute to Behçet's disease (BD). METHODS: We performed a genome-wide association study using DNA samples from a Korean population consisting of 379 BD patients and 800 controls. A replication study was performed in a Japanese population (363 BD patients and 272 controls). To evaluate the functional implication of the target single nucleotide polymorphisms (SNP), gene expression levels in peripheral T cells, allele-specific modulation of promoter activity and biological effect of mRNA knockdown were investigated. RESULTS: We found a novel association of BD to the GIMAP locus, mapped to chromosome 7q36.1 (rs1608157, p=6.01×10(-8) in a minor allele dominant model; rs11769828, allele based p=1.60×10(-6)). A fine mapping study identified an association with four additional SNP: rs1522596 (OR=1.45, p=7.70×10(-6)) in GIMAP4; rs10266069 (OR=1.32, p=2.67×10(-4)) and rs10256482 (OR=1.27, p=5.27×10(-4)) in GIMAP2; and rs2286900 (OR=1.61, p=3.53×10(-5)) in GIMAP1 areas. Replication study using DNA samples from the Japanese population validated the significant association between BD and the GIMAP locus. The GIMAP4 promoter construct plasmid with the minor allele of rs1608157 displayed significantly lower activity than one with the major allele. Moreover, CD4 T cells from BD patients showed a lower level of GIMAP4 mRNA, and GIMAP4 knockdown was protective against Fas-mediated apoptosis. CONCLUSIONS: These results suggest that a GIMAP cluster is a novel susceptibility locus for BD, which is involved in T-cell survival, and T-cell aberration can contribute to the development of BD.

Particulate matter in school buildings: Influence of influx control of outdoor PM particles and building renovation in summer.

The hazardous effects of air pollution on the human body are of grave concern, particularly the rising levels of 2.5 µm-particulate matter. Children are more susceptible to the lethal effects of particulate matter (PM) than adults. In this study, a case study of architectural renovation (ARCH-R) and facility renovation (FAC-R) was conducted in a school by focusing on the exit and entrance gates. In addition, the PM influx rate was evaluated. To evaluate the influx rate of PM, opening/closing recognition equipment and particle sensors were utilized. Following the renovation, the result was evaluated. During the daytime, the air curtain led to a reduction in the influx rate of PM of approximately 8% when the door was open. During the nighttime, it was confirmed that the fine dust influx rate was reduced through reinforcement of the door. However, regarding using these two measures in combination, it was confirmed that the concentration of PM increased in the corridor when the air curtain was operated while the door was closed. It was confirmed that both ARCH-R and FAC-R are necessary for controlling the influx of fine dust from the outdoor air. Appropriate operating guidelines should be provided for school operators.

Pt cocatalyst morphology on semiconductor nanorod photocatalysts enhances charge trapping and water reduction.

In photocatalysis, metal-semiconductor hybrid structures have been proposed for ideal photocatalytic systems. In this study, we investigate the effect of morphology and surface nature of Pt cocatalysts on photocatalytic hydrogen evolution activity in Pt-tipped CdSe nanorods. Three distinct morphologies of Pt cocatalysts were synthesized and employed as visible light photocatalysts. The rough tips exhibit the highest activity, followed by the round and cubic tips. Kinetic investigations using transient absorption spectroscopy reveal that the cubic tips exhibit lower charge-separated states feasible for reacting with water and water reduction rates due to their defectless surface facets. In contrast, the rough tips show a similar charge-separation value but a two-fold higher surface reaction rate than the round tips, resulting in a significant enhancement of hydrogen evolution. These findings highlight the importance of rational design on metal cocatalysts in addition to the main semiconductor bodies for maximizing photocatalytic activities.