This study presents a novel approach that integrates ozone-driven chemical oxidation to convert NO into soluble NO2, followed by the simultaneous absorption of NO2 and SO2 into a CaCO3-based slurry using the redox catalyst potassium iodide (KI). Using cyclic voltammetry, we demonstrate the redox properties of the I2/2I- couple, which facilitates NO2 reduction into soluble NO2- and catalyst regeneration through sulfite (SO32-)-driven reduction, thus establishing a closed catalytic cycle within the components of flue gas. In lab-scale wet-scrubbing tests, we explore the effect of various operational parameters (i.e., KI concentration, pH, and SO2 concentration), with a 15 h stability test demonstrating >60% NOx and >99% SO2 removal efficiency when the pH is controlled between 7.5 and 8.5. A successful pilot-scale implementation conducted at an inlet flow rate of 1000 m3 h-1 further confirmed the reproducibility of the proposed redox-catalytic cycle. Our study offers a cost-effective, sustainable, and scalable solution for effectively mitigating NOx and SO2 emissions at low temperatures.

In the contemporary context, executing light-oxidant- and reductant-driven reactions in solution-phase processes remains challenging mainly due to the lack of general tools for understanding the reactive potential of nano-functional catalysts. In this study, dual-active nanometals (Au and Cu doped with Au) capped within soy lecithin (SL), were developed and characterized, combining flexibility with the catalytic advantages and stability of liquid-phase catalysts. The as-synthesized SL-Au (LG) and SL-Au-Cu (LGC) catalysts were efficiently degraded rhodamine B (RB, 100%) in the presence of H2O2 under light irradiation (350 W lamp) at wide pH range (3-7) within 4.5 h and p-nitrophenol (p-NP, >90% degradation at pH 7) in the presence of NaBH4 under normal stirring with slower kinetics (∼72 h). RB degradation followed a pseudo-second-order kinetic model with a higher r2, and p-NP degradation followed first-order kinetics. The active sites embedded within the structural order of SL arrangement displayed elevated catalytic activity, which was further enhanced by the movement of intermediate/excited states and charged elements within the metal suspended in the phospholipid (LG and LGC). The self-regulating tunability of the physicochemical characteristics of these catalysts provides a convenient and generalizable platform for the transformation of modern dual-active (redox) catalysts into dynamic homogeneous equivalents.

Organic electrosynthesis has been widely used as an environmentally conscious alternative to conventional methods for redox reactions because it utilizes electric current as a traceless redox agent instead of chemical redox agents. Indirect electrolysis employing a redox catalyst has received tremendous attention, since it provides various advantages compared to direct electrolysis. With indirect electrolysis, overpotential of electron transfer can be avoided, which is inherently milder, thus wide functional group tolerance can be achieved. Additionally, chemoselectivity, regioselectivity, and stereoselectivity can be tuned by the redox catalysts used in indirect electrolysis. Furthermore, electrode passivation can be avoided by preventing the formation of polymer films on the electrode surface. Common redox catalysts include N-oxyl radicals, hypervalent iodine species, halides, amines, benzoquinones (such as DDQ and tetrachlorobenzoquinone), and transition metals. In recent years, great progress has been made in the field of indirect organic electrosynthesis using transition metals as redox catalysts for reaction classes including C-H functionalization, radical cyclization, and cross-coupling of aryl halides-each owing to the diverse reactivity and accessible oxidation states of transition metals. Although various reviews of organic electrosynthesis are available, there is a lack of articles that focus on recent research progress in the area of indirect electrolysis using transition metals, which is the impetus for this review.

Sorghum (Sorghum bicolor (L.) Moench) produces a range of defense phytochemicals containing a quinone core structure: sorgoleone allelochemical, flavonoid phytoalexins, and a broad spectrum of polyphenols. Those phytochemicals react with the components of cellular and agroecosystems to form stable semiquinone radicals engaging in different proton-coupled electron transfer reactions. This unique redox reactivity of plant phenolics could be used to develop bioactive food ingredients and green pesticides. To achieve those application goals, chemical phenotyping methods sensitive to quinone-semiquinone-dihydroxybenzene redox cycles (e.g., electrochemical conversion with fluorescence detection) are in demand. Chemometrics-based fingerprinting tools could facilitate on-farm screening of target traits for breeding innovations.

A microplate method is described for the quantification of p-nitrophenol (p-NPh) in urine samples where it can be found after exposure to certain insecticides such as methyl parathion or paraoxon. The assay is based on the use of a polydopamine (PDA) film doped with gold nanoparticles (AuNPs). The latter exerts a catalytic effect on the reduction of nitrophenols by NaBH4. PDA has adhesive properties and can be used to fix the AuNPs on several solid substrates, here ELISA polystyrene microwells. The optical and catalytic properties of different populations of AuNPs spontaneously grown on PDA films were investigated, mainly in terms of the relationship between AuNPs@PDA nanocomposite preparation and its catalytic activity and stability. The reduction of o-, m-, and p-nitrophenols by NaBH4 in aqueous solution was exploited as model study. The approach demonstrates that useful kinetic information on the catalytic effect can be obtained on 96-wells simultaneously by a conventional ELISA reader at a fixed wavelength of 415 nm. The method was successfully applied to the quantification of p-NPh in (spiked) urine samples and gave high reproducibility (RSD = 3.5%) and a 6.30 μM (836 μg/L) detection limit. Graphical abstract Schematic presentation of 96-wells preparation for optical quantification on ELISA reader of p-nitrophenol (p-NPh) catalytic reduction to p-aminophenol (p-APh), as model study, by NaBH4 and different population gold nanoparticles (AuNPs) grown on polydopamine (PDA) films attached onto polystyrene (PS) wells.

An efficient electrocatalytic functionalization of N-arylglycine esters is reported. The protocol proceeds in an undivided cell under constant current conditions employing the simple, cheap and readily available n-Bu4NI as the mediator. In addition, it is demonstrated that the mediated process is superior to the direct electrochemical functionalization.