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Atomic‐level tailoring of active sites is an efficient strategy for designing high‐performance photocatalysts for clean energy. Asymmetric atomic sites (AAS) like MSA‐Ov‐M2 created through hetero‐metal single atoms (MSA) doping on defect‐rich metal oxides (M2‐Ov‐M2) are favored for better activation of targeted molecules. However, creating AAS typically demands high energy input, hindering their widespread use in photocatalytic H2 production. Furthermore, precise control over surface defects to create AAS remains challenging. Here, CuSA‐Ov‐Ti3c highly asymmetric atomic sites catalyst (HAASC) is constructed by strategically trapping Cu single atoms on high‐index (111) faceted TiO2. This material combines single‐atom catalysis and facet engineering, achieving unprecedented H2 production rates (8.3 mmol h−1 g−1 in pure water and 784.5 mmol h−1 g−1 in water/methanol mixture). Experimental and theoretical analyses reveal CuSA substituting five‐coordinated Ti atoms (Ti5c) next to three‐coordinated (Ti3c) ones, forming CuSA‐Ov‐Ti3c HAAS. HAAS plays multiple roles in i) improving light harvesting, charge‐transfer dynamics, and redox capability of photoexcited electrons; ii) enhanced adsorption and polarization of H2O molecules; iii) facilitating electron transfer from CuSA‐Ov‐Ti3c to H2O molecules, and iv) raising d‐band center toward Fermi level resulting in ≈250‐fold enhanced H2 production than Ti5c‐O‐Ti3c AASC. This work opens new avenues for future structural designs in heterogeneous catalysis for energy‐related applications. [ABSTRACT FROM AUTHOR]

In this study, three different solvent systems have been employed to investigate the effect of reaction parameters on the synthesis of four alkaline earth metal-based MOFs namely [Ca(0.5 1,4-phenyl diacetic acid)2(H2O)DMF]∞ (Ca-MOF-1), [Ca(1,4-naphthalene dicarboxylate)DMF]∞ (Ca-MOF-2), [Ca2(0.5 1,2,4,5-benzene tetracarboxylate)2(H2O)3DMF]∞ (Ca-MOF-3) and [Ca2(2,6-naphthalene dicarboxylate)2(H2O)6]∞ (Ca-MOF-4). The crystal structures of these four MOFs have been resolved through single crystal X-ray analysis and the bulk phase purity of these MOFs was assessed using PXRD and FT-IR analysis. To check the stability of these MOFs, thermogravimetric analysis (TGA) was carried out. To analyze the robustness of these MOFs, the PXRD of the samples was also collected at different pH levels. These MOFs were further explored as Lewis acid catalysts for the alcoholysis of epoxides and the activity of these catalysts depend on the open metal sites present in the MOFs. The catalytic activity follows the order: Ca-MOF-2 > Ca-MOF-4 > Ca-MOF-1 > Ca-MOF-3. The activity was also checked with various epoxide substrates using Ca-MOF-2. Density functional theory (DFT) calculations also support this trend with the help of the thermodynamic feasibility of epoxide binding, considering model MOF structures. The weak interaction between the epoxide oxygen and the metal centre of the most stable MOF structure has also been clarified by computational studies. [ABSTRACT FROM AUTHOR]

A simple and reliable method based on a composite of Nafion (Naf), multiwalled carbon nanotubes (MWCNTs), and mesoporous silica (SBA-15) modified glassy carbon electrode (GCE) is reported for individual and simultaneous determination of indigo carmine (IC, dye) and carbendazim (CBZ, pesticide). SBA-15 was synthesized and characterized and used to design a GCE/Naf/MWCNTs/SBA-15 sensor, which was characterized by electrochemical techniques and used for the determination of IC and CBZ. Using the optimum conditions for differential pulse voltammetry (DPV), the peak currents were linear from 1.0 µM to 11.0 µM. The limits of detection for individual measurements were 0.50 µM and 0.57 µM for IC and CBZ, respectively, while those for simultaneous detection were 0.28 µM and 0.30 µM. The interferences studies show that GCE/Naf/MWCNTs/SBA-15 exhibited excellent selectivity. The developed procedure was successfully applied to determine IC and CBZ in spring, tap, and lake water. [ABSTRACT FROM AUTHOR]

Synthesis and catalytic application of polymeric-based nanocomposites are important subjects among researchers due to their high lipophilicity as well as high chemical and mechanical stability. In the present work, a novel nanocomposite material involving ionic liquid and high-density polyethylene supported tungstate (PE/IL-WO4=) is synthesized, characterized and its catalytic application is investigated. The coacervation method was used to incorporate 1-methyl-3-octylimidazolium bromide ([MOIm] [Br]) ionic liquid in high-density polyethylene, resulting in a PE/IL composite. Subsequently, tungstate was anchored on PE/IL to give PE/IL-WO4= catalyst. The PXRD, FTIR, EDX, TGA, and SEM analyses were used to characterize the PE/IL-WO4= composite. This material demonstrated high catalytic efficiency in the synthesis of bioactive tetrahydrobenzo[a]xanthen-11-ones under green conditions. The recoverability and leching tests were performed to investigate the stability and durability of the designed PE/IL-WO4= catalyst under applied conditions. [ABSTRACT FROM AUTHOR]

Chemical fixation of CO2 for the synthesis of valuable chemicals is very demanding in the context of green and sustainable chemistry. Herein, we report highly efficient silver‐loaded porous organic polymer catalysts for the exclusive N‐formylation and N‐methylation of amines under ambient reaction conditions using CO2 as a green C1 source. By adjusting the solvent and temperature of the reaction, the successful production of formamides and methylamines could be accomplished with high levels of selectivity and efficiency. POP‐based materials Ag@TTP‐1 and Ag@PAN‐T are utilized as low‐cost catalysts for both the N‐methylation and N‐formylation of primary and secondary amines and the product yields up to 98 % could be achieved. Ag@TTP‐1 demonstrated superior catalytic efficiency compared to Ag@PAN‐T in the N‐methylation and N‐formylation reactions. This result suggests that the grafting of Ag nanoparticles onto POP surface with a high surface area plays a crucial role in these CO2 fixation reactions. The above‐mentioned catalysts (Ag@TTP‐1 and Ag@PAN‐T) are characterized through powder XRD, FT IR spectroscopy, FE‐SEM, TEM, thermogravimetric techniques, N2 sorption and XPS analysis. Ag‐nanocatalysts demonstrated heterogeneous nature and high recycling efficiency for several cycles in this CO2 fixation reaction. [ABSTRACT FROM AUTHOR]

Mitochondrial topisomerase 1 (Top1mt) is critical for mtDNA replication, transcription, and energy production. Here, we investigate the carrier-mediated targeted delivery of the anticancer drug irinotecan into the mitochondria to selectively trap Top1mt covalent complexes (Top1mtcc) and its role in anticancer therapeutics. We have designed a biocompatible mesoporous metal–organic framework (MOF) material, namely MIL-101(Fe), as the drug delivery carrier that selectively localizes inside mitochondria. In contrast to the traditional way of synthesising MOFs, here we have employed a vapour-assisted solvothermal method for the synthesis of MIL-101(Fe) using terephthalic acid as the organic linker and Fe(III) as the metal source. The advantage of this method is that it recycles the excess solvent (DMF) and reduces the amount of washing solvent. We demonstrate that MIL-101(Fe)-encapsulated irinotecan (MIL-Iri) was selectively targeted towards the mitochondria to poison Top1mtcc in a dose-dependent manner and was achieved at a low nanomolar drug concentration. We provide evidence that Top1mtcc generated by MIL-Iri leads to mtDNA damage in human colon and breast cancer cells and plays a significant role in cellular toxicity. Altogether, this study provides evidence for a new and effective strategy in anticancer chemotherapy. [ABSTRACT FROM AUTHOR]

The emergence of non‐precious metal‐based robust and economic bifunctional oxygen electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial for the rational design of commercial rechargeable Zn‐air batteries (RZAB) with safe energy conversion and storage systems. Herein, a facile strategy to fabricate a cost‐efficient, bifunctional oxygen electrocatalyst Fe3C/Fe decorated N doped carbon (FeC‐700, the catalyst prepared at carbinization temperature of 700 °C) with a unique structure has been developed by carbonization of a single source precursor, tetrabutylammonium tetrachloroferrate(III) complex. The ORR and OER activity revealed excellent performance (ΔE=0.77 V) of the FeC‐700 electrocatalyst, comparable to commercial Pt/C and RuO2, respectively. The designed temperature‐tuneable structure provided sufficiently accessible active sites for the continuous passage of electrons by shortening the mass transfer pathway, leading to extremely durable electrocatalysts with high ECSA and amazing charge transfer performance. Remarkably, the assembled Zn‐air batteries with the FeC‐700 catalyst as the bifunctional air electrode delivers gratifying charging‐discharging ability with an impressive power density of 134 mW cm−2 with a long lifespan, demonstrating prodigious possibilities for practical application. [ABSTRACT FROM AUTHOR]

Hydrogen production via water splitting is instrumental in harvesting zero-carbon green energy. Hydrazine oxidation reaction (HzOR) is recognized as a replacement for the slothful anodic oxygen evolution reaction. However, agonizingly, HzOR gets hampered due to its high working potential in contrast to its low theoretical value and the usage of high-cost precious metal-based electrocatalysts to lower the overpotential. Additionally, the slow nature of the cathodic oxygen reduction reaction (ORR) is experienced by noble metal (Pt)-based catalysts, which have the shortcomings of being uneconomical and suffer from the methanol crossover effect. Thus, developing nonprecious metal-based economic bifunctional electrocatalysts catalyzing HzOR and ORR is imperative. Herein, we designed a simple strategy to synthesize manganese oxide nanorods loaded in mesoporous carbon (CKT) as a bifunctional electrocatalyst for boosting the anodic HzOR and cathodic ORR in alkaline media. The as-synthesized MnO2/CKT nanocomposite shows excellent response toward HzOR with a low onset potential of 0.7 V vs RHE and achieved a current density of 10 mA cm–2 at a potential of 0.88 V vs RHE. MnO2/CKT nanocomposite also displayed a Tafel slope (105 mV decade–1) and a maximum current density of 25.6 mA cm–2 at a potential of 1.4 V vs RHE in the presence of 50 mM hydrazine hydrate in 1 M KOH. Furthermore, the MnO2/CKT electrocatalyst can also reduce molecular oxygen with similar efficiency to the state-of-the-art Pt/C catalyst through an efficient 4-electron pathway with an improved onset potential of 0.95 V vs RHE and a current density of −4.5 mA cm–2 in O2-saturated 0.1 M KOH. The electrochemical impedance spectroscopy and chronoamperometric (i–t) responses of the electrocatalyst showed the feasibility of rapid electron transfer and high stability at the interface. The promising bifunctional electrocatalytic efficiency of the unique MnO2/CKT nanocomposite initiates from the synergetic physicochemical characteristics of MnO2 and CKT, enabling smooth analyte diffusion with low charge transfer resistance and offering a superior quantity of active sites for the catalytic reactions. [ABSTRACT FROM AUTHOR]

Selective electrochemical oxidation of alcohols to their corresponding aldehydes or acids utilizing water as the oxygen source is not only considered a green and sustainable approach to synthesize value added chemicals but also economically demanding as the overall process is coupled with green H2 production. However, restricted production due to low current density and the use of expensive noble-metal-based electrocatalysts has limited its industrial viability. On the other hand microwave-assisted synthesis enables a rapid, economical and effective way to fabricate various advanced porous materials. In this regard, herein we report microwave assisted rapid synthesis of a metal–organic framework materials ZIF-9 nanocrystals and ZIF-9@xGO composites by varying the wt% of graphene oxide (GO). Remarkably, upon GO loading the current density increases significantly from 75 mA cm−2 to 204 mA cm−2 at 1.6 V vs. RHE in an alkaline solution with 0.1 M benzyl alcohol, thereby imparting direct impact towards benzoic acid yield (∼84%) and faradaic efficiency (∼88%) of the process. Moreover, the optimised electrocatalyst (i.e. ZIF-9@10GO) exhibits a H2 evolution rate of 273 mmol g−1 h−1 in the presence of benzyl alcohol. Our results indicate that in situ generated Co(OH)2/CoOOH hybrid species over the ZIF-9 surface plays an active role in this electrocatalysis. Additionally, this electrocatalytic system shows good functional group tolerance, exhibiting wide scope for different substrates with high faradaic efficiency. [ABSTRACT FROM AUTHOR]

The selective electrocatalytic oxidative upgradation of 5-hydroxymethylfurfural (HMF) is a promising approach to synthesize 2,5-furandicarboxylic acid (FDCA), an alternative bio-based precursor for the production of polymers. Coupling the anodic upgradation reaction with industrially important cathodic reactions such as hydrogen generation would increase the energy efficiency in electrochemical water splitting. Herein, we demonstrate the synthesis of a ternary heterostructure based on NixSy, MoS2, and MoC supported on onion-like carbon for anodic HMF valorization. The heterostructured electrocatalyst efficiently catalyzes the selective oxidation of HMF to FDCA with 100% faradaic efficiency (FE) and yield. The complete conversion of HMF to FDCA is achieved in 65 min. The catalytic activity is evaluated in terms of FE and rate of production of FDCA (0.463 mmolFDCA mmolHMF−1 h−1 cm−2). The anodic valorization is achieved at 190 mV less positive potential with respect to the oxygen evolution reaction, supporting the strong electrocatalytic effect of the heterostructured catalyst. The availability of a large number of active sites due to abundant heterojunctions favors the facile electron transfer kinetics at a favorable potential. The catalyst is highly stable and reusable to deliver 100% yield even after 8 consecutive cycles without any compromise in the FE. The anodic oxidation of HMF is paired with the cathodic hydrogen evolution reaction using a cathode electrocatalyst. An observable negative shift (180 mV) in the cell voltage with respect to the oxygen evolution reaction is achieved with the paired electrocatalytic system, demonstrating the excellent activity of the catalyst. [ABSTRACT FROM AUTHOR]

Porous organic polymers (POPs) have attracted substantial attentions over the years due to their exceptionally high specific surface areas, high chemical stability of the organic network and ease of surface functionalization with the desired organic groups. In this work, a triazine based POP (TrzPOP) was synthesized through Schiff base polycondensation reaction between a tetramine bearing triazine rings and phenolic–OH group rich dialdehyde. Ni nanoparticles (NiNP) synthesized independently were immobilized over TrzPOP to obtain the NiNP@TrzPOP composite catalyst. This TrzPOP possesses a high BET surface area of 1494 m2 g−1 and low band gap, which facilitates its role as visible light absorbent. NiNP@TrzPOP with N‐rich surfaces and phenolic–OH moieties displayed excellent photocatalytic activity in the CO2 photoreduction under mild reaction conditions. NiNP@TrzPOP composite selectively reduces CO2 to methanol. The turn over number (TON) for this photoreduction of CO2 under optimized reaction conditions is 270, which is considerably high comparing to other reported photocatalytic systems. Moreover, NiNP@TrzPOP composite catalytic system showed high recycling efficiency without noticeable decrease in its performance over five consecutive reaction cycles, suggesting its huge potential for large‐scale methanol synthesis from the renewable carbon source. [ABSTRACT FROM AUTHOR]