Moringa oleifera (Moringa) seeds contain a natural cationic protein (MOCP) that can be used as an antimicrobial flocculant for water clarification. Currently, the main barrier to using Moringa seeds for producing potable water is that the seeds release other water-soluble proteins and organic matter, which increase the concentration of dissolved organic matter (DOM) in the water. The presence of this DOM supports the regrowth of pathogens in treated water, preventing its storage and later use. A new strategy has been established for retaining the MOCP protein and its ability to clarify and disinfect water while removing the excess organic matter. The MOCP is first adsorbed and immobilized onto sand granules, followed by a rinsing step wherein the excess organic matter is removed, thereby preventing later growth of bacteria in the purified water. Our hypotheses are that the protein remains adsorbed onto the sand after the functionalization treatment, and that the ability of the antimicrobial functionalized sand (f-sand) to clarify turbidity and kill bacteria, as MOCP does in bulk solution, is maintained. The data support these hypotheses, indicating that the f-sand removes silica microspheres and pathogens from water, renders adhered Escherichia coli bacteria nonviable, and reduces turbidity of a kaolin suspension. The antimicrobial properties of f-sand were assessed using fluorescent (live-dead) staining of bacteria on the surface of the f-sand. The DOM that can contribute to bacterial regrowth was shown to be significantly reduced in solution, by measuring biochemical oxygen demand (BOD). Overall, these results open the possibility that immobilization of the MOCP protein onto sand can provide a simple, locally sustainable process for producing storable drinking water.

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It is frequently desired to synthesize supported metal catalysts that consist of very small clusters or single atoms. In this work, we combine strong electrostatic adsorption (SEA) of H2PtCl6 and engineered oxide supports to ultimately produce very small Pt clusters, including a large fraction of single Pt atoms. The supports are synthesized by depositing controlled amounts of SiO2 onto Al2O3 (SiO2@Al2O3) that has been previously grafted with bulky organic templates. After the templates are removed, the oxide supports are largely negatively charged, like SiO2, but have small patches of positively charged Al2O3, derived from the regions previously covered by the template. The overall point of zero charge of these materials decreases from pH 6.4 for 1 cycle of SiO2 deposition to a SiO2-like <2 for materials with more than 5 cycles of SiO2 deposition. SEA at pH 4 on templated SiO2@Al2O3 deposits from 1 wt. % to 0.05 wt. % Pt as the amount of SiO2 increases. Pt loadings drop to near zero in the absence of a template. The resulting Pt nanoparticles are generally <1 nm and have dispersion near 100% by CO chemisorption. Finally, CO DRIFTS shows that the CO nanoparticles become increasingly well defined and have a higher percentage of Pt single atoms as the amount of SiO2 increases on the SiO2@Al2O3 particles. Overall, this method of synthesizing patches of charge on a carrier particle appears to be a viable route to creating extremely highly dispersed supported metal catalysts.

Group VI sulfides were synthesized via coprecipitation of elemental sulfur and metal hexacarbonyl and characterized with XRD, XPS, and TEM. These materials were then demonstrated as active catalysts for the acceptorless dehydrogenative coupling of neat ethanol to ethyl acetate, rapidly reaching equilibrium conversion and up to 90% selectivity. Other primary alcohols form the corresponding esters, while diols formed the corresponding cyclic ethers and oligomers.

Bulk and supported MoS x materials have gained interest as alternative catalysts for light alkane dehydrogenation, but there is little kinetic data published with which rigorous comparisons can be made to other catalysts. Here, rates, selectivities, and activation barriers are collected under conditions of differential conversion for the dehydrogenation of isobutane over various morphologies of molybdenum sulfide. We find that a "rag-like" MoS 2 composed of small, disordered crystallites exhibits higher catalytic rates than layered, highly crystalline MoS 2 (52 vs 2.7 μmol ks −1 g cat −1 at 360 °C). This is in part not only due to increased surface area but also due to intrinsically more active edge and defect sites exposed by the rag-like structure, as shown by a decrease in apparent activation energy from 61 to 43 kJ mol −1 . Supporting MoS x on metal oxides or metal organic frameworks gives small MoS x clusters that have up to 7-fold higher rates per mass of MoS 2 than even the rag-like MoS 2 . Rates are support-dependent, with the highest rates per mass of MoS 2 observed over MoS x /TiO 2 . Pt/Al 2 O 3 has a ∼50-fold higher rate than the best MoS 2 catalysts (2700 μmol ks −1 g cat −1 at 360 °C), but it has an apparent activation energy of 41 kJ mol −1 , similar to that of the rag-like MoS 2 . Therefore, the rates over MoS 2 appear to be limited by a small number of active sites on the surface, rather than intrinsically poor activity. Given the data provided in this manuscript and the enormous phase space available to metal sulfides, these materials warrant further investigation as alternative light alkane dehydrogenation catalysts, especially for use under conditions that would deactivate a precious metal catalyst.