Green synthesized AgNPs decorated on Ketjen black for enhanced catalytic dye degradation

Green synthesized Zn-based mono and bi-metallic nanoparticles for improved micronutrient delivery: A futuristic study in hydroponic crop culture system

Hydroponic farming is gaining importance due to the rapid expansion of cities worldwide. However, the significance of nano-enabled nutrient delivery in hydroponic crop culture is still poorly understood. Therefore, ZnO monometallic and Zn-Cu bimetallic nanoparticles (MNP and BNP) were innovatively synthesized through green routes using alcoholic leaf extract (ALE) 1-10 % (w/v) of Chrysalidocarpus lutescens due to its enriched phytochemical profile, prolific radical scavenging efficiency, and reasonably high IC50 values. The structural uniformity and batch-wise yield of MNP and BNP were optimized following response surface methodology. The uniqueness of C. lutescens-derived phytochemicals facilitated the production of anisotropic and crystalline MNP and BNP. It was revealed that structural uniformity and yields were most significant at pH 9 with 3 % ALE for both MNP (Yield/batch -20.54 ± 0.15 g) and BNP (Yield/batch - 18.37 ± 0.30 g). Both nanoparticles were hexagonal 30-85 nm nanocrystals, stable at alkaline pH (∼9) with uniform pore volume, surface area, and surface charge. The hydroponic compatibility of the MNP and BNP were compared with non-nanoscale Zn and Cu by cultivating Cicer arietinum with different doses of MNP, BNP, and other treatments. Among all doses, 250 and 500 mg L-1 doses of MNP and BNP significantly augmented C. arietinum germination by ∼40-45 % and plumule growth by ∼18-22 % and enhanced chlorophyll stability while reducing oxidative stress in the seedlings. The MNP and BNP were ecologically safe for microorganisms (Rhizobium sp. and Salmonella typhi) and were viable within 250 mg L-1 to 2000 mg L-1 of MNP and BNP doses. Overall, the study reveals that the green synthetic routes using C. lutescens phytoextract led to significant yield of productive, biocompatible, and organically rich Zn and Cu-based MNP and BNP that can be easily pursued and sustainably applied in hydroponics or other agriculture platforms.

Morphology regulation during mechanochemistry synthesis activating nanostructured aluminum lithium storage behavior

Aluminum (Al) is a potential anode material for lithium-ion batteries due to its high theoretical capacity and low volume expansibility. However, scalable fabrication of nanostructured Al still faces a great challenge. In addition, the lithium storage performance of Al anode materials always encounters a severe strike within a dozen discharge/charge cycles, and such an abnormal behavior of the Al anode material remains enigmatic. Herein, a mechanochemistry method without using any solvent is developed to achieve scalable production of Al nanoparticles and the morphology of the obtained Al nanoparticles could be regulated using Ketjen black (KB). KB with a chain-like structure could regulate the Al crystal growth process and the aggregation of Al nanoparticles during the solid-phase reaction, shortening the electron transfer path among Al crystals, ultimately activating the lithium storage behavior of nanostructured Al. Initial discharge/charge capacities of 630.6 and 402.0 mA h g-1 were achieved at 50 mA g-1; unfortunately, the nanostructured Al still suffered from rapid deterioration of lithium storage performance. Comprehensive analysis demonstrated that the raised energy barrier of LiAl formation and the slow lithium diffusion kinetics in the Al matrix may be the main factors destroying the lithium storage performance of the Al anode material. This work provided more evidence for illustrating the lithium storage behavior of the Al anode.

Boosting Antibacterial Photodynamic Therapy in a Nanosized Zr MOF by the Combination of Ag NP Encapsulation and Porphyrin Doping

Antibacterial photodynamic therapy (aPDT) is regarded as one of the most promising antibacterial therapies due to its nonresistance, noninvasion, and rapid sterilization. However, the development of antibacterial materials with high aPDT efficacy is still a long-standing challenge. Herein, we develop an effective antibacterial photodynamic composite UiO-66-(SH)2@TCPP@AgNPs by Ag encapsulation and 4,4',4″,4‴-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) (TCPP) dopant. Through a mix-and-match strategy in the self-assembly process, 2,5-dimercaptoterephthalic acid containing -SH groups and TCPP were uniformly decorated into the UiO-66-type framework to form UiO-66-(SH)2@TCPP. After Ag(I) impregnation and in situ UV light reduction, Ag NPs were formed and encapsulated into UiO-66-(SH)2@TCPP to get UiO-66-(SH)2@TCPP@AgNPs. In the resulting composite, both Ag NPs and TCPP can effectively enhance the visible light absorption, largely boosting the generation efficiency of reactive oxygen species. Notably, the nanoscale size enables it to effectively contact and be endocytosed into bacteria. Consequently, UiO-66-(SH)2@TCPP@AgNPs show a very high aPDT efficacy against Gram-negative and Gram-positive bacteria as well as drug-resistant bacteria (MRSA). Furthermore, the Ag NPs were firmly anchored at the framework by the high density of -SH moieties, avoiding the cytotoxicity caused by the leakage of Ag NPs. By in vitro experiments, UiO-66-(SH)2@TCPP@AgNPs show a very high antibacterial activity and good biocompatibility as well as the potentiality to promote cell proliferation.

Nickel-Based Metal-Organic Frameworks as Electrocatalysts for the Oxygen Evolution Reaction (OER)

The exploration of earth-abundant electrocatalysts with high performance for the oxygen evolution reaction (OER) is eminently desirable and remains a significant challenge. The composite of the metal-organic framework (MOF) Ni₁₀Co-BTC (BTC = 1,3,5-benzenetricarboxylate) and the highly conductive carbon material ketjenblack (KB) could be easily obtained from the MOF synthesis in the presence of KB in a one-step solvothermal reaction. The composite and the pristine MOF perform better than commercially available Ni/NiO nanoparticles under the same conditions for the OER. Activation of the nickel-cobalt clusters from the MOF can be seen under the applied anodic potential, which steadily boosts the OER performance. Ni₁₀Co-BTC and Ni₁₀Co-BTC/KB are used as sacrificial agents and undergo structural changes during electrochemical measurements, the stabilized materials show good OER performances.