Integrated CO2 Capture and Dry Reforming of CH4 to Syngas: A Review.

Integrating carbon capture with dry reforming of methane offers a promising approach to addressing greenhouse gas emissions while producing valuable syngas. This review examines the complexities and progress made in this integrated process, wherein catalysts play a critical role in adsorbing carbon dioxide and facilitating the conversion of methane to syngas. The chemical process entails the concurrent capture of CO2 emissions and their usage in dry reforming, a reaction in which CH4 interacts with CO2 to generate syngas, an essential precursor for various industrial applications. The dual-functional materials can adsorb carbon dioxide and actively reform to an end-use application. The much-studied Ca-based sorbents exhibit a theoretical carbon capture capacity of 17.8 mmol g-1. However, during practical exploration of these materials as a dual-functional catalyst for integrated carbon capture and the dry reforming of methane, the uptake reduces to ∼13 mmol g-1 carbon capacity with 96.5 and 96% conversions of CO2 and CH4, respectively. Therefore, a thorough analysis of the complex relationship between CO2 capture and CH4 reforming catalysis is attempted herein based on various reported materials. Design concepts, structural optimization, and performance evaluation analysis of the dual-functional materials reveal their importance in carbon capture and reformation technology. Additionally, this review covers the field difficulties, future perspectives, and attractive commercial implementation predictions. This scrutiny illustrates the significance of dual-functional materials for sustainable energy production and environmental protection.

Discerning toxic nerve gas agents via a distinguishable 'turn-on' fluorescence response: multi-stimuli responsive quinoline derivatives in action.

We have successfully synthesized quinoline derivatives that exhibit easy scalability and responsiveness to multiple stimuli. These derivatives are capable of forming self-assembled nanoscopic aggregates in an aqueous medium. Consequently, when placed in an aqueous environment, we observe dual fluorescence originating from both twisted intramolecular charge transfer and aggregation-induced emission. The introduction of nerve gas agents, such as diethyl chlorophosphate (DClP) or diethylcyanophosphate (DCNP), to the probe molecules facilitates the charge-transfer process, resulting in a red-shift in absorption maxima. Notably, when operating in fluorescence mode, both of these analytes produce distinct output signals, making them easily distinguishable. DCNP generates a blue fluorescence, while the addition of DClP yields cyan fluorescence. Our mechanistic investigation reveals that the initial step involves phosphorylation of the quinoline nitrogen end. However, in the case of DCNP, the released cyanide ion subsequently attacks the carbonyl carbon centre, forming a cyanohydrin derivative. The response to these target analytes appears to be influenced by the nucleophilicity of the quinoline nitrogen end and the electrophilic nature of the carbonyl unit.

Electro-Oxidation Reaction of Methanol over La2-xSrxNi1-y(Mn/Fe/Co)yO4+δ Ruddlesden-Popper Oxides.

Solution combustion-synthesized Ruddlesden-Popper oxides La1.4Sr0.6Ni0.9(Mn/Fe/Co)0.1O4+δ were explored for the methanol electro-oxidation reaction. With optimal doping of Sr2+ in the A site and Co2+ in the B site, Ni3+ with t2g6 dx2-y21 configuration in La1.4Sr0.6Ni0.9Co0.1O4+δ exhibited a tetragonal distortion with compression in axial bonds and elongation in equatorial bonds. This structural modification fostered an augmented overlap of dz2 orbitals with axial O 2p orbitals, leading to a heightened density of states at the Fermi level. Consequently, this facilitated not only elevated electrical conductivity but also a noteworthy reduction in the charge transfer resistance. These effects collectively contributed to the exceptional methanol oxidation activity of La1.4Sr0.6Ni0.9Co0.1O4+δ, as evidenced by an impressive current density of 21.4 mA cm-2 and retention of 95% of initial current density even after 10 h of prolonged reaction. The presence of Ni3+ further played a pivotal role in the creation of NiOOH, a crucial intermediate species, facilitated by the presence of surface oxygen vacancies. These factors synergistically enabled efficient methanol oxidation. In summary, our present study not only yields substantial insights but also paves the way for a novel avenue to fine-tune the activity of Ruddlesden-Popper oxides for the successful electro-oxidation of methanol.

High activity in the dry reforming of methane using a thermally switchable double perovskite and in situ generated molecular level nanocomposite.

This work emphasizes the dry reforming of methane (DRM) reaction on citrate sol-gel-synthesized double perovskite oxides. Phase pure La2NiMnO6 shows very impressive DRM activity with H2/CO = 0.9, hence revealing a high prospect of next-generation catalysts. Although the starting double perovskite phase gets degraded into mostly binary oxide phases after a few hours of DRM activity, the activity continues up to 100 h. The regeneration of the original double perovskite out of decomposed phases by annealing at near synthesis temperature, followed by the spectacular retention of activity, is rather interesting and hitherto unreported. This result unravels unique reversible thermal switching between the original double perovskite phase and decomposed phases during DRM without compromising the activity and raises challenge to understand the role of decomposed phases evolved during DRM. We have addressed this unique feature of the catalyst via structure-property relationship using the in situ generated molecular level nanocomposite.

Dnajb11-Kidney Disease Develops from Reduced Polycystin-1 Dosage but not Unfolded Protein Response in Mice.

SIGNIFICANCE STATEMENT: Heterozygous DNAJB11 mutation carriers manifest with small cystic kidneys and renal failure in adulthood. Recessive cases with prenatal cystic kidney dysplasia were recently described. Our in vitro and mouse model studies investigate the proposed disease mechanism as an overlap of autosomal-dominant polycystic kidney disease and autosomal-dominant tubulointerstitial kidney disease pathogenesis. We find that DNAJB11 loss impairs cleavage and maturation of the autosomal-dominant polycystic kidney disease protein polycystin-1 (PC1) and results in dosage-dependent cyst formation in mice. We find that Dnajb11 loss does not activate the unfolded protein response, drawing a fundamental contrast with the pathogenesis of autosomal-dominant tubulointerstitial kidney disease. We instead propose that fibrosis in DNAJB11 -kidney disease may represent an exaggerated response to polycystin-dependent cysts. BACKGROUND: Patients with heterozygous inactivating mutations in DNAJB11 manifest with cystic but not enlarged kidneys and renal failure in adulthood. Pathogenesis is proposed to resemble an overlap of autosomal-dominant polycystic kidney disease (ADPKD) and autosomal-dominant tubulointerstitial kidney disease (ADTKD), but this phenotype has never been modeled in vivo . DNAJB11 encodes an Hsp40 cochaperone in the endoplasmic reticulum: the site of maturation of the ADPKD polycystin-1 (PC1) protein and of unfolded protein response (UPR) activation in ADTKD. We hypothesized that investigation of DNAJB11 would shed light on mechanisms for both diseases. METHODS: We used germline and conditional alleles to model Dnajb11 -kidney disease in mice. In complementary experiments, we generated two novel Dnajb11-/- cell lines that allow assessment of PC1 C-terminal fragment and its ratio to the immature full-length protein. RESULTS: Dnajb11 loss results in a profound defect in PC1 cleavage but with no effect on other cystoproteins assayed. Dnajb11-/- mice are live-born at below the expected Mendelian ratio and die at a weaning age with cystic kidneys. Conditional loss of Dnajb11 in renal tubular epithelium results in PC1 dosage-dependent kidney cysts, thus defining a shared mechanism with ADPKD. Dnajb11 mouse models show no evidence of UPR activation or cyst-independent fibrosis, which is a fundamental distinction from typical ADTKD pathogenesis. CONCLUSIONS: DNAJB11 -kidney disease is on the spectrum of ADPKD phenotypes with a PC1-dependent pathomechanism. The absence of UPR across multiple models suggests that alternative mechanisms, which may be cyst-dependent, explain the renal failure in the absence of kidney enlargement.

Zika virus triggers autophagy to exploit host lipid metabolism and drive viral replication.

BACKGROUND: Zika virus (ZIKV), an arbovirus of global concern, has been associated with neurological complications including microcephaly in newborns and Guillain-Barré syndrome in adults. Like other flaviviruses, ZIKV depends on cholesterol to facilitate its replication; thus, cholesterol has been proposed as a therapeutic target to treat the infection using FDA-approved statins. Cholesterol is stored in intracellular lipid droplets (LD) in the form of cholesterol esters and can be regulated by autophagy. We hypothesize that the virus hijacks autophagy machinery as an early step to increase the formation of LD and viral replication, and that interference with this pathway will limit reproduction of virus. METHODS: We pretreated MDCK cells with atorvastatin or other inhibitors of autophagy prior to infection with ZIKV. We measured viral expression by qPCR for NS1 RNA and immunofluorescence for Zika E protein. RESULTS: Autophagy increases in virus-infected cells as early as 6 h post infection (hpi). In the presence of atorvastatin, LD are decreased, and cholesterol is reduced, targeting key steps in viral replication, resulting in suppression of replication of ZIKV is suppressed. Other both early- and late-acting autophagy inhibitors decrease both the number of LD and viral replication. Bafilomycin renders cholesterol is inaccessible to ZIKV. We also confirm previous reports of a bystander effect, in which neighboring uninfected cells have higher LD counts compared to infected cells. CONCLUSIONS: We conclude that atorvastatin and inhibitors of autophagy lead to lower availability of LD, decreasing viral replication. We conclude that bafilomycin A1 inhibits viral expression by blocking cholesterol esterification to form LD. Video Abstract.

Rags to Riches: Meliorating the Electrocatalytic Reduction of Nitrate to Ammonia over Cu-Based Nanoalloys.

The selective electrocatalytic reduction of nitrate pollutants into valuable ammonia products has gained significant momentum thanks to the emerging circular economy model. However, this technology suffers from poor selectivity, low Faradic efficiency, and a competing parallel hydrogen evolution reaction. In this regard, the use of nanoalloys offers a promising approach to fine-tune the electronic structure by shifting the position of the d-band center and modulating the interaction with nitrate and other reaction intermediates and thus enhance the selectivity of desirable products, which may not be accessible over a pristine single metallic active site. Herein, we have systematically doped Cu (d9s2) by Ni (d8s2) and Zn (d10s2) to produce Cu0.85Ni0.15/C and Cu0.85Zn0.15/C, respectively, from the corresponding bimetallic metal-organic framework materials. A thorough investigation of electrocatalytic nitrate reduction over the as-synthesized nanomaterials was done by studying the product yield, selectivity, Faradic efficiency, reaction order, rate, and activation energy. The synthesized carbon-supported nanoalloy of Cu0.85Zn0.15/C outperformed both Cu0.85Ni0.15/C and Cu/C, and the superiority was rationalized by the first-principles calculation, which unveiled the significance of the modulation of the d-bands in influencing the interaction of nitrate and other reaction intermediates with the surface, thereby enhancing the selectivity and catalytic efficacy.

Photo- and Electrocatalytic Reduction of CO2 over Metal-Organic Frameworks and Their Derived Oxides: A Correlation of the Reaction Mechanism with the Electronic Structure.

A Ce/Ti-based bimetallic 2-aminoterephthalate metal-organic framework (MOF) was synthesized and evaluated for photocatalytic reduction of CO2 in comparison with an isoreticular pristine monometallic Ce-terephthalate MOF. Owing to highly selective CO2 adsorption capability, optimized band gaps, higher flux of photogenerated electron-hole pairs, and a lower rate of recombination, this material exhibited better photocatalytic reduction of CO2 and lower hydrogen evolution compared to Ce-terephthalate. Thorough probing of the surface and electronic structure inferred that the reducibility of Ce4+ to Ce3+ was due to the introduction of an amine functional group into the linker, and low-lying Ti(3d) orbitals in Ce/Ti-2-aminoterephthalate facilitated the photoreduction reaction. Both the MOFs were calcined to their respective oxides of Ce1-xTixO2 and CeO2, and the electrocatalytic reduction of CO2 was performed over the oxidic materials. In contrast to the photocatalytic reaction mechanism, the lattice substitution of Ti in the CeO2 fluorite cubic structure showed a better hydrogen evolution reaction and consequently, poorer electroreduction of CO2 compared to pristine CeO2. Density functional theory calculations of the competitive hydrogen evolution reaction on the MOF and the oxide surfaces corroborated the experimental findings.

Optimization of prostate cancer cell detection using multiplex tyramide signal amplification.

Approximately 29 000 men die of prostate cancer (PCa) each year in the United States, and 90% to 100% of them are due to incurable bone metastasis. It is difficult to determine (1) when PCa disseminates in the natural history of the disease; (2) where cancer cell disseminates before becoming overt metastatic lesions; and (3) which tumors are aggressive and which are indolent. Tumor tissue and liquid (blood and bone marrow) biopsies provide important information to answer these questions, but significant limitations exist for immunostaining strategies that assess protein expression in these tissues. Classic immunohistochemistry (IHC) assays can typically assess expression of one or two proteins per tissue section. We have developed a novel immunofluorescence staining protocol to detect a panel of seven proteins on PCa tissue from primary tumor biopsies and metastatic lesion autopsy tissue, as well as cancer cells from liquid biopsies. We used a tyramide-based system to amplify the true signal and optimized the protocol to reduce background signal, thereby boosting the signal-to-noise ratio. Any protein-specific antibody in this protocol can be exchanged for a different validated antibody. This protocol therefore, represents a highly informative and flexible assay that can be used to provide important information about cancer tissue for the purpose of improving detection, diagnosis, and treatment.

Zeolite-Based Sorbent for CO2 Capture: Preparation and Performance Evaluation.

In this work, zeolite-based sorbents were developed from gasified rice husk. CO2 capture capacity of the sorbents was examined at various temperatures and pressures employing a fixed-bed flow reactor and simulated flue gas. Various physicochemical properties such as thermal stability, pore size distribution, morphology, chemical composition, etc. of the in-house-developed materials were characterized in detail and were also compared with two commercially available zeolites. Tetra-ethylenepentamine was impregnated in the in-house-developed zeolite supports to investigate its suitability to improve the CO2 adsorption capacity. The effects of reactor pressure, temperature, Si/Al ratio, and amine loading on CO2 uptake capacity were examined. A declining trend in CO2 adsorption capacity was observed with the increase in adsorption temperature and amine loading. At 30 °C, zeolite-Y (designated as Z-Y-3, silica to alumina ratio of 2.25) sample exhibited maximum adsorption capacity, and the obtained values were around 114 and 190 mg CO2/g sorbent under atmospheric and 5 bar pressure, respectively. It was also observed that the presence of alkali metal ions influenced the adsorption capacity of the zeolites. The study inferred that the adsorbent was efficient and promising for multiple adsorption-desorption cycles without much deterioration of the capture capacity.

Determination of band edges and their influences on photocatalytic reduction of nitrobenzene by bulk and exfoliated g-C3N4.

Thermally and chemically exfoliated metal-free semiconducting g-C3N4 are synthesized from bulk g-C3N4. Thorough characterization of the synthesized materials is performed with the help of XRD, FTIR, FE-SEM, PL, surface area analysis and DRS to probe differences in structural, morphological and optical properties between thermally and chemically exfoliated g-C3N4. The synthesized materials are exposed to light for photocatalytic reduction of nitrobenzene. The complete reduction reaction mechanism and product selectivity over the synthesized catalysts are studied in this report. The rate of reduction of nitrobenzene is found to be higher with thermally exfoliated g-C3N4, and the selectivity of aniline is found to be higher in the case of chemical exfoliated g-C3N4. The differences in the reactivity are explained in terms of structure, surface morphologies and band edge positions.

An Overview of the Unfolded Protein Response (UPR) and Autophagy Pathways in Human Viral Oncogenesis.

Autophagy and Unfolded Protein Response (UPR) can be regarded as the safe keepers of cells exposed to intense stress. Autophagy maintains cellular homeostasis, ensuring the removal of foreign particles and misfolded macromolecules from the cytoplasm and facilitating the return of the building blocks into the system. On the other hand, UPR serves as a shock response to prolonged stress, especially Endoplasmic Reticulum Stress (ERS), which also includes the accumulation of misfolded proteins in the ER. Since one of the many effects of viral infection on the host cell machinery is the hijacking of the host translational system, which leaves in its wake a plethora of misfolded proteins in the ER, it is perhaps not surprising that UPR and autophagy are common occurrences in infected cells, tissues, and patient samples. In this book chapter, we try to emphasize how UPR, and autophagy are significant in infections caused by six major oncolytic viruses-Epstein-Barr (EBV), Human Papilloma Virus (HPV), Human Immunodeficiency Virus (HIV), Human Herpesvirus-8 (HHV-8), Human T-cell Lymphotropic Virus (HTLV-1), and Hepatitis B Virus (HBV). Here, we document how whole-virus infection or overexpression of individual viral proteins in vitro and in vivo models can regulate the different branches of UPR and the various stages of macro autophagy. As is true with other viral infections, the relationship is complicated because the same virus (or the viral protein) exerts different effects on UPR and Autophagy. The nature of this response is determined by the cell types, or in some cases, the presence of diverse extracellular stimuli. The vice versa is equally valid, i.e., UPR and autophagy exhibit both anti-tumor and pro-tumor properties based on the cell type and other factors like concentrations of different metabolites. Thus, we have tried to coherently summarize the existing knowledge, the crux of which can hopefully be harnessed to design vaccines and therapies targeted at viral carcinogenesis.

The role of reducibility vis-à-vis oxygen vacancies of doped Co3O4/CeO2 in the oxygen evolution reaction.

Electrochemical water splitting, which is a highly promising and environmentally friendly technology for H2 fuel production, faces significant hurdles due to the sluggish kinetics of the oxygen evolution reaction. Co -based oxides have garnered significant attention as alternative catalysts for the oxygen evolution reaction owing to the Co2+/Co3+ redox couple. Enhancing the challenging Co2+ → Co3+ oxidation process can further improve the catalytic oxygen evolution reaction. The aim of our work was to design a Co3O4-based catalyst to enhance reactivity by increasing the number of Co3+ active sites, serving as an excellent platform for facilitating the oxygen evolution reaction. To drive the effectiveness of the catalyst, in this study, we synthesized Co3O4 anchored on CeO2 (Co3O4/CeO2). The kinetics and efficacy of the oxygen evolution reaction catalysed by Co3O4/CeO2 was significantly improved by aliovalent doping of Sr into Ce sites and Cu into Co sites. The reducible nature of Ce stimulates the formation of Co3+ ions, resulting in an increased production of intermediate -OOH species, thus expediting the reaction. The transformation of Co2+ to Co3+ consequently leads to an increase in anion vacancies, which, in turn, promotes the adsorption of more intermediate species at the active site. The Sr- and Cu-doped Co3O4/CeO2 catalyst exhibited a high current density of 200 mA cm-2 at 580 mV and a low overpotential of 297 mV at 10 mA cm-2. The study functions as a key indicator to establish a connection between oxygen vacancies and metal oxidation states in order to investigate the mechanistic aspects of the oxygen evolution reaction on mixed metal oxides. Moreover, this study is expected to pave the way for the development of innovative oxygen evolution reaction catalysts with reducible supports, thus offering a new pathway for their design.

Prolonged administration of intrathecal baclofen in a patient with generalized grade 4 tetanus.

INTRODUCTION: This case report presents the management of a 62-year-old woman with generalized grade 4 tetanus, focusing on the innovative use of intrathecal baclofen (ITB) therapy. The patient initially presented with a laceration and subsequently developed severe tetanic spasms, necessitating interventions beyond standard tetanus immunoglobulin and antibiotics due to the condition's progressive and life-threatening nature. The preference for ITB over oral baclofen is highlighted, considering ITB's enhanced bioavailability in the central nervous system and its efficacy in reducing spinal cord reflexes, which is critical for managing severe spasticity.On her return to the emergency department with symptoms of tetanus, the patient received ITB following the failure of oral baclofen to control the spasms. ITB administration necessitated a lumbar drain, which was later substituted with a tunneled intrathecal catheter due to the extended requirement for baclofen infusion and the unavailability of suitable infusion pumps. This scenario represented a significant application of a CADD-Solis external pump for continuous ITB infusion.Transitioning the patient from ITB to oral baclofen was a crucial management step to facilitate discharge and recovery, underscoring the importance of a careful approach to prevent withdrawal symptoms and maintain care continuity. Despite initial complications, including an infection signaled by leucocytosis and confirmed through cerebrospinal fluid culture, the patient was effectively treated and discharged. CONCLUSION: This report contributes to the sparse literature on prolonged ITB use for generalized grade 4 tetanus treatment, underlining the need for interdisciplinary collaboration for the best patient outcomes. It showcases the potential of ITB in spasticity management, in reducing the need for sedation, and in shortening the duration of mechanical ventilation, advocating for a tailored approach that utilizes a full spectrum of pharmacological and supportive therapies.

Reconstitution of human microglia and resident T cells in the brain of humanized DRAGA mice.

Humanized mouse models are valuable tools for investigating the human immune system in response to infection and injury. We have previously described the human immune system (HIS)-DRAGA mice (HLA-A2.HLA-DR4.Rag1KO.IL-2RgKO.NOD) generated by infusion of Human Leukocyte Antigen (HLA)-matched, human hematopoietic stem cells from umbilical cord blood. By reconstituting human cells, the HIS-DRAGA mouse model has been utilized as a "surrogate in vivo human model" for infectious diseases such as Human Immunodeficiency Virus (HIV), Influenza, Coronavirus Disease 2019 (COVID-19), scrub typhus, and malaria. This humanized mouse model bypasses ethical concerns about the use of fetal tissues for the humanization of laboratory animals. Here in, we demonstrate the presence of human microglia and T cells in the brain of HIS-DRAGA mice. Microglia are brain-resident macrophages that play pivotal roles against pathogens and cerebral damage, whereas the brain-resident T cells provide surveillance and defense against infections. Our findings suggest that the HIS-DRAGA mouse model offers unique advantages for studying the functions of human microglia and T cells in the brain during infections, degenerative disorders, tumors, and trauma, as well as for testing therapeutics in these pathological conditions.

Morphologically tuned CuO-ZnO-CeO2 catalyst for CO2 hydrogenation to methanol.

Morphologically modified composite CuO-ZnO-CeO2 catalysts were synthesized using a single-step hydrothermal technique. The study highlights the influence of solvent on the structural and physico-chemical properties of the catalysts. Various techniques, such as XRD, FE-SEM, BET, XPS, and H2-TPR, were used to analyze the catalyst properties. Among the synthesized materials, the catalyst, prepared with a N,N-dimethyl formamide (DMF)-to-metal nitrates ratio of 20 (named as CZC-1), showed enhanced active sites in the form of surface features such as nanowire-like morphology, large surface area, low crystallite size, increased oxygen vacancies, and high CuO dispersion. A bench-scale fixed-bed flow reactor was used to examine the catalytic performance of the catalysts. At 225 °C reactor temperature, 30 bar reactor pressure, and with a space velocity of 6000 cm3 gcat-1 h-1, the CZC-1 catalyst showed 13.6% CO2 conversion and 74.1% methanol selectivity. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis confirmed the carbonate-formate-methoxy reaction pathway for methanol formation using the CZC-1 catalyst.

Electro-oxidation Reaction of Methanol over Reducible Ce1-x-yNixSryO2-δ: A Mechanistic Probe of Participation of Lattice Oxygen.

Methanol oxidation reaction crucially depends on the formation of -OOH species over the catalyst's surface. Ni-based catalysts are by far the choice of materials, where the redox couple of Ni2+/Ni3+ facilitates the formation of -OOH species by surface reconstructions. However, it is challenging to oxidize Ni2+ as it generates charge-transfer orbitals near the Fermi energy level. One possible solution is to substitute Ni2+ with a reducible oxide support, which will not only facilitate the Ni2+ → Ni3+ oxidation but also adsorb oxygenated species like -OOH at a lower potential owing to its oxophilicity. This work shows with the help of structural and surface studies that the reducible CeO2 support in Ni and Sr co-doped Ce1-x-yNixSryO2-δ solid solution can easily facilitate Ni2+ → Ni3+ oxidation as well as evolution of lattice oxygen during the methanol oxidation reaction. While the Ni3+ species helped in formation of -OOH surface intermediates, the evolved lattice oxygen eased the CO oxidation process in order to bring out the better CO-tolerant methanol oxidation activity over Ce1-x-yNixSryO2-δ. The study shows the unique importance of the electronic interactions between the active site and support and involvement of lattice oxygen in the methanol oxidation reaction.

Technological solutions for NOx, SOx, and VOC abatement: recent breakthroughs and future directions.

NOx, SOx, and carbonaceous volatile organic compounds (VOCs) are extremely harmful to the environment, and their concentrations must be within the limits prescribed by the region-specific pollution control boards. Thus, NOx, SOx, and VOC abatement is essential to safeguard the environment. Considering the importance of NOx, SOx, and VOC abatement, the discussion on selective catalytic reduction, oxidation, redox methods, and adsorption using noble metal and non-noble metal-based catalytic approaches were elaborated. This article covers different thermal treatment techniques, category of materials as catalysts, and its structure-property insights along with the advanced oxidation processes and adsorption. The defect engineered catalysts with lattice oxygen vacancies, bi- and tri-metallic noble metal catalysts and non-noble metal catalysts, modified metal organic frameworks, mixed-metal oxide supports, and their mechanisms have been thoroughly reviewed. The main hurdles and potential achievements in developing novel simultaneous NOx, SOx, and VOC removal technologies are critically discussed to envisage the future directions. This review highlights the removal of NOx, SOx, and VOC through material selection, properties, and mechanisms to further improve the existing abatement methods in an efficient way.

Synthesis of dihydropyrimidinones via multicomponent reaction route over acid functionalized Metal-Organic framework catalysts.

Multi component reactions over heterogeneous solid acid catalysts are extremely important owing to easy separation, amenable recycling, and prospective scaling up of the process. Here, we are reporting the synthesis of biologically important dihydropyrimidinones over postsynthetic modified Cr-based metal-organic framework materials as heterogeneous catalysts containing the bifunctional Lewis and Brønsted acid sites. Cr-based metal-organic frameworks contained coordinatively unsaturated metal sites as inherent Lewis acid sites, whereas postsynthetic modifications introduced the Brønsted acid sites in the framework. A direct one pot synthesis route was employed to produce the pristine MOF in pure aqueous medium without using any additives. The bulk structure, morphology, surface and bonding properties of the synthesized materials were thoroughly characterized with powder XRD, FTIR, XPS, FE-SEM, TGA, and N2 sorption isotherms. A qualitative evolution of acid strength was carried out over the functionalized MOFs. Among the post synthetic functionalized materials, carboxylic acid functionalized framework exhibited a very high yield of dihydropyrimidinones under solvent less moderate reaction conditions. The catalyst also demonstrated a robust recyclability and wide substrate scope. Comparative study showed a very high catalytic activity of the postsynthetic modified MOFs in comparison to the reported literature. The reaction condition was optimized by varying parameters like solvent, temperature, reaction duration and catalyst loadings. The mechanistic studies indicated the involvement of both the Lewis and Brønsted sites acid sites of the catalysts in the multicomponent reaction.