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Dynamic restructuring of bimetallic catalysts plays a crucial role in their catalytic activity and selectivity. In particular, catalyst pretreatment with species such as carbon monoxide and oxygen has been shown to be an effective strategy for tuning the surface composition and morphology. Mechanistic and kinetic understanding of such restructuring is fundamental to the chemistry and engineering of surface active sites but has remained challenging due to the large structural, chemical, and temporal degrees of freedom. Here, we combine time-resolved temperature-programmed infrared reflection absorption spectroscopy, ab initio thermodynamics, and machine-learning molecular dynamics to uncover previously unidentified timescale and kinetic parameters of in situ restructuring in Pd/Au(111), a highly relevant model system for dilute Pd-in-Au nanoparticle catalysts. The key innovation lies in utilizing CO not only as a chemically sensitive probe of surface Pd but also as an agent that induces restructuring of the surface. Upon annealing in vacuum, as-deposited Pd islands became encapsulated by Au and partially dissolved into the subsurface, leaving behind isolated Pd monomers on the surface. Subsequent exposure to 0.1 mbar CO enabled Pd monomers to repopulate the surface up to 373 K, above which complete Pd dissolution occurred by 473 K, with apparent activation energies of 0.14 and 0.48 eV, respectively. These restructuring processes occurred over the span of ∼1000 s at a given temperature. Such a minute-timescale dynamics not only elucidates the fluxional nature of alloy catalysts but also presents an opportunity to fine-tune the surface under moderate temperature and pressure conditions.

A novel way to remove fouling from forward osmosis membrane is carried out in this research work. Electric field was used as a novel fouling removal option in this research work. Therefore, conductive membrane was prepared with the use of chitosan (CHS), polyvinyl alcohol (PVA), and graphene (Gr). The prepared membrane named as “CHS/PVA/Gr”. Various characterization methods are used to characterized this CHS/PVA/Gr membrane i.e. conductivity, porosity, swelling ratio, water flux measurement, and scanning electron microscopy (before and after fouling). To check the CHS/PVA/Gr membrane performance and fouling behavior forward osmosis (FO) experiments are carried out with distilled water (DI water) and algae-containing water. In FO experiments, as a feed solution algae water (nearby lake water) and as a draw agent, high concentration NaCl solution (4 M NaCl) was used. Membrane fouling and draw solution leakage was investigated in this research work by laboratory-scale forward osmosis (FO) setup. The water flux in FO mode was 31.2 Lm−2 h−1(LMH) (with DI water as a feed) and reverse salt diffusion 0.015 gm−2 h−1(gMH). The initial FO water flux value is 28.1 LMH with algae-containing water. Intention of fouling removal method is to regain the initial water flux after giving cleaning treatment in IC current the form of elect. After cleaning experiments, the restore water flux values are 14.2 and 22.04 LMH for distilled water and electric field cleaning method, respectively. [ABSTRACT FROM AUTHOR]

Confined nanosized spaces at the interface between a metal and a seemingly inert material, such as a silicate, have recently been shown to influence the chemistry at the metal surface. In prior work, we observed that a bilayer (BL) silica on Ru(0001) can change the reaction pathway of the water formation reaction (WFR) near room temperature when compared to the bare metal. In this work, we looked at the effect of doping the silicate with Al, resulting in a stoichiometry of Al0.25Si0.75O2. We investigated the kinetics of WFR at elevated H2 pressures and various temperatures under interfacial confinement using ambient pressure X-ray photoelectron spectroscopy. The apparent activation energy was lower than that on bare Ru(0001) but higher than that on the BL-silica/Ru(0001). The apparent reaction order with respect to H2 was also determined. The increased residence time of water at the surface, resulting from the presence of the BL-aluminosilicate (and its subsequent electrostatic stabilization), favors the so-called disproportionation reaction pathway (*H2O + *O ↔ 2 *OH), but with a higher energy barrier than for pure BL-silica. [ABSTRACT FROM AUTHOR]