Mg, Mn and Fe as environmental-friendly elements were introduced into the laminates of layered double hydroxides (LDHs) to synthesize MgMnFe-LDHs for peroxymonosulfate (PMS) activation to degrade imidacloprid (IMI). The catalytic activity of MgMnFe-LDHs was influenced by the Mn content in the LDH laminates, and Mg2Mn1Fe with Mn/Mg = 0.5 exhibited superior performance that 250 mg/L of dosage achieving 93.1 % degradation of IMI (10 mg/L) by activating PMS (0.65 mM) within 30 min. The mesoporous structure facilitated the contact between PMS and active sites, the abundant surface hydroxyl groups (-OH) provided sites for PMS complexation, and the synergism of Mn and Fe promoted PMS adsorption and electron transfer ability of Mg2Mn1Fe, thereby accelerating the production of SO4 center dot- and center dot OH. The primary active sites were identified by density functional theory calculations that H-O-I-O-II-SO3- is absorbed through the binding of OI site with -OH of Mg2Mn1Fe, and the adsorption is more likely to occur on -OH connected with Mg-Mn-Fe rather than Mg-Mg-Fe and Mg-Mg-Mn. Based on the identification of degradation products, the degradation reaction types of IMI were proposed, including the opening of imidazole ring, carbonylation, denitrification, hydroxylation, dechlorination, and N-dealkylation. This study provides new insights into the design of efficient and environmentally-friendly LDH-based catalysts for PMS activation and the interaction mechanism between PMS and hydroxyl groups in LDH laminates.

In this work, we propose an automated, real-time optical scanning approach to assessing catalyst performance in the process of nitro-to-amine reduction using well-plate readers to monitor reaction progress. This approach takes advantage of a simple on–off fluorescence probe that gives a shift in absorbance and strong fluorescent signal when the non-fluorescent nitro-moiety is reduced to the amine form. The combination of an affordable probe and a low barrier-to-entry technique provides an accessible approach to high-throughput catalyst screening. Under this paradigm, we screened 114 different catalysts and compared them in terms of reaction completion times, material abundance, price, recoverability, and safety. Using a simple scoring system, we plotted the catalysts in terms of cumulative scores, along with some intentional biases, including an emphasis on preference for catalysts with potential as green catalysts, considering environmental issues and possible geopolitical preferences.

Contaminated drinking water is a major health hazard in large urban areas as well as remote communities. Several pollutants detected in rivers and lakes are hormone disruptors that are harmful to consumers as well as aquatic life. In this contribution, we present a new material, synthesized using novel green technologies, designed for solar- or LED-driven degradation of pollutants. This material is based on a glass fiber support, loaded with black TiO2, a modified form of TiO2 with strong visible light absorption and without any toxic metal or non-metal dopants. This photocatalyst is fully compatible with flow applications. The effectiveness of the catalyst is demonstrated with crocin and 17β-estradiol, the former being a natural carotenoid used as a screening tool and the latter being a common hormonal disruptor. Our work shows that under visible light illumination, our supported black TiO2 can degrade these water contaminants with greater efficiency than conventional TiO2. We envision that our findings can contribute to the production of inexpensive, large-scale solar or LED-based water decontamination systems that could be rapidly deployed to sites in need. Operation of such systems would require minimal training and could be monitored remotely. In addition to the catalyst’s non-toxicity and inflow compatibility, the material also has a long shelf life and is easy and inexpensive to produce, making it an attractive candidate for developing water treatment devices.

The semi-hydrogenation reaction of alkynes is important in the fine chemicals and pharmaceutical industries, and it is thus important to find catalytic processes that will drive the reaction efficiently and at a low cost. The real challenge is to drive the alkyne-to-alkene reaction while avoiding over-hydrogenation to the saturated alkane moiety. The problem is more difficult when dealing with aromatic substitution at the alkyne center. Simple photocatalysts based on Palladium tend to proceed to the alkane, and stopping at the alkene with good selectivity requires very precise timing with basically no timing tolerance. We report here that the goal of high conversion with high selectivity could be achieved with TiO2-supported copper (Cu@TiO2), although with slower kinetics than for Pd@TiO2. A novel bimetallic catalyst, namely, CuPd@TiO2 (0.8% Cu and 0.05% Pd), with methanol as the hydrogen source could improve the kinetics by 50% with respect to Cu@TiO2, while achieving selectivities over 95% and with exceptional timing tolerance. Further, the low Palladium content minimizes its use, as Palladium is regarded as an element at risk of depletion.

Palladium nanostructures are interesting heterogeneous catalysts because of their high catalytic activity in a vast range of highly relevant reactions such as cross couplings, dehalogenations, and nitro-to-amine reductions. In the latter case, the catalyst Pd@GW (palladium on glass wool) shows exceptional performance and durability in reducing nitrobenzene to aniline under ambient conditions in aqueous solutions. To enhance our understanding, we use a combination of optical and electron microscopy, in-flow single molecule fluorescence, and bench chemistry combined with a fluorogenic system to develop an intimate understanding of Pd@GW in nitro-to-amine reductions. We fully characterize our catalyst in situ using advanced microscopy techniques, providing deep insights into its catalytic performance. We also explore Pd cluster migration on the surface of the support under flow conditions, providing insights into the mechanism of catalysis. We show that even under flow, Pd migration from anchoring sites seems to be minimal over 4 h, with the catalyst stability assisted by APTES anchoring.

We propose the photopolymerization of lipoic acid (LA) as an novel approach to produce a cross-linked polymeric matrix of lipoic acid monomers (PALA) which helps to control the size of plasmonic gold nanostructures when using 3,3,6,8-tetramethyl-1-tetralone as the photo-initiator for the reduction of Au(III) to Au0. A complete characterization of the polymer is included, and the dual behaviour of LA as an in situ stabilizer and reducing agent is investigated. These findings are relevant to the understanding of the photochemical transformation of this biologically relevant compound and would benefit the increasing use of LA and PALA for the synthesis of various nanomaterials.

To develop new flow-compatible high-performance catalysts in the nitro-to-amine reduction, Pd@GW was fully characterized by the combination of fluorescence, in-flow single molecule fluorescence, and electron microscopy.

Contaminated drinking water is a major health hazard in large urban areas as well as remote communities. Several pollutants detected in untreated wastewater are hormonal disruptors which are harmful to consumers as well as aquatic life. In this contribution, we present a novel material designed for visible light driven decontamination of water. This material is based on a glass fiber support loaded with black TiO2, a modified form of TiO2 with an expanded light absorption capacity without any toxic metal or non-metal dopants. The photocatalyst developed in our laboratories is ideal for flow as the active material remians fixed while there is continous passage of solution occuring under visible light irradiation. The effectiveness of the catalyst is demonstrated with crocin and 17β-estradiol, the former being a natural carotenoid used as a screening tool, and the latter being a common hormonal disruptor. Our work shows that under visible light illumination, our supported black TiO2 is able to degrade these water contaminants with greater efficiency than conventional TiO2. Using this framework we envision that our findings can contribute to the production of inexpensive, large-scale solar or LED-based water decontamination systems which would be rapidly deployable to sites in need. Operation of such systems would require minimal training and could be monitored remotely. In addition to the catalyst’s non-toxicity and in-flow compatibility, the material also has a long shelf life and is easy and inexpensive to produce, making it an attractive candidate for developing water treatment devices

The photolysis of vanillin produces a short-lived triplet state where its lifetime is controlled by efficient self-quenching (k(SQ) similar to 2 x 10(9) m(-1) s(-1)) which also generates radicals. Free radical reactions, including vanillin dimer formation, are responsible for the degradation of vanillin and is accompanied by yellowing of the acetonitrile solutions. Laser flash photolysis studies reveal a triplet absorbing at 390 nm, readily quenched by naphthalenes, conjugated dienes and oxygen. Vanillin is also a good singlet oxygen sensitizer as revealed by its characteristic NIR emission at 1270 nm.

A single-molecule microscopy study of the interaction of dye-modified alkanes, alkenes, and alkynes with nanostructured catalysts based on TiO2 reveals significant differences in the desorption kinetics of the probe molecules depending on the chemical nature of the catalyst. A comparison of TiO2 with materials decorated with palladium (Pd@TiO2) or molybdenum/cobalt (MoCo@TiO2) reveals kinetic differences that in part justify the better performance of MoCo@TiO2 in semihydrogenation reactions. Whereas the single-molecule desorption rate is similar to 50% higher for MoCo@TiO2 than Pd@TiO2, analysis at the bench scale indicate alkene-to-alkane conversion is around 10 times faster for Pd (k(2)(Pd) = 0.02 s(-1)) than for MoCo (k(2)(MoCo) = 0.002 s(-1)) catalysts. This suggests selectivity is not solely determined by the desorption processes and that the hydrogenation rate constant (k(21)) for the on-surface hydrogenation of alkenes to alkanes is much faster for Pd@TiO2 than for MoCo@TiO2. Thus, the latter shows greater selectivity toward partial hydrogenation reactions compared with Pd@TiO2, whose great hydrogenation performance becomes a disadvantage for the selectivity needed for semihydrogenation processes.

We explored the functionalization of the inexpensive commercial dye Red GG through a simple one-pot Grignard reaction leading to novel substituted derivatives that were incorporated into organic thin film transistors.

Earth abundant materials, Mo and Co, are used to decorate TiO2 and work as co-catalyst for the selective semi-hydrogenation of alkynes and isomerization of estragole in a H-2-free environment under UVA irradiation. Catalytic efficiency is higher than highly-reactive Pd-decorated TiO2, using lower metal loadings and showing better selectivity towards the semi-hydrogenation reaction. (C) 2019 Elsevier Inc. All rights reserved.

Heterogeneous catalysis presents significant advantages over homogeneous catalysis such as ease of separation and reuse of the catalyst. Here we show that a very inexpensive, manageable and widely available material - glass wool - can act as a catalyst support for a number of different reactions. Different metal and metal oxide nanoparticles, based on Pd, Co, Cu, Au and Ru, were deposited on glass wool and used as heterogeneous catalysts for a variety of thermal and photochemical organic reactions including reductive de-halogenation of aryl halides, reduction of nitrobenzene, Csp(3)-Csp(3) couplings, N-C heterocycloadditions (click chemistry) and Csp-Csp(2) couplings (Sonogashira couplings). The use of glass wool as a catalyst support for important organic reactions, particularly C-C couplings, opens the opportunity to develop economical heterogeneous catalysts with excellent potential for flow photo-chemistry application.

Glass wool – a very inexpensive, widely available and easily handled material – is a versatile catalyst support for heterogeneous catalysis.

Single-molecule spectroscopy is used to gain insights into the click chemistry reaction photocatalyzed by copper. We show that CuxO@Nb2O5 catalysts can act as truly heterogeneous photocatalysts and that the amine plays an important role in the complexation between the alkyne and the copper active site on the catalyst surface. For complex reactions occurring in the subnanomolar range, preassociation can be essential and cocatalysts (such as amines here) may play an enabling role facilitating the reagents "reunion" and prolonging the time available for reaction. This provides a rational analysis of the amine role in heterogeneous photocatalytic click chemistry.

An open SSF process using B. coagulans LA1507 introduces an effective way to produce l-lactic acid from abundant SSB.

A magnetically separatable catalyst Fe3O4@SiO2@PEI@Au (gold) nanoparticle was successfully constructed by a novel regional selective photoreduction method. Based on the photolysis mechanism of a type II photoinitiator, through controlling the distribution of polyethylene imine (PEI), Au nanoparticles about 10 nm, which are only on the surface of the Fe3O4@SiO2@PEI nanoparticle, could be photoreduced due to the PEI acting as a coordinating agent, capping agent, and photoreducing agent simultaneously. The small size Au nanoparticles endow the catalyst with a high catalytic performance toward the reduction of 4-nitroaniline to 4-aminophenol by NaBH4. In addition, magnetic Fe3O4@SiO2@PEI@Au nanoparticles could easily be recovered and could be reused at least six times still keeping catalytic efficiency higher than 95%, which contributes to their high stability and magnetization. Furthermore, compared to another reported approach, this method showed great regional selectivity of reducing metal nanoparticles by controlling the distribution of the PEI. Taking advantage of the regional selectivity of the photoreducing method could also be used to fabricate other metal nanoparticles as catalysts for various reactions.

Copper-doped semiconductors are designed to photoassist the alkyne-azide cycloaddition catalysis by Cu(I). Upon irradiation, injection of electrons from the semiconductor into copper oxide nanostructures produces the catalytic Cu(I) species. The new catalysts are air- and moisture-tolerant and can be readily recovered after use and reused several times.

In this paper, a two-step method to fabricate a large-scale flexible conductive pattern via direct photo-patterning and “volume additive process on demand” theory was developed. The copper pattern was formed on the surface of the flexible substrate directly by photo-reduction. However, the copper pattern was not conductive due to the discontinuous structure. Fusion growth of particles was achieved via the “volume additive process on demand” to realize the pattern conductivity without sintering. This method is simple, efficient, low-cost and environmentally friendly, especially for heat sensitive substrate to fabricate large-scale conductive pattern. In addition, “volume additive process on demand” theory could be extended to other preparation methods of metal pattern, such as inkjet printing, to meet the new requirement of electronic industry in the future.

Single molecule spectroscopy (SMS) inspired the optimization of a heterogeneous 'click' catalyst leading to enhanced yields of the Cu-catalyzed reaction of azides with terminal alkynes. Changes in SMS data after optimization confirm the improvements in catalyst performance.