The Temporal Analysis of Products (TAP) experiment provides an unparalleled level of kinetic insight into heterogenous catalytic materials, but due to the complex and expensive instrumentation required, its application has been limited to a small group of dedicated researchers. Herein we demonstrate through a series of designs that precisely defined TAP experiments can be performed on systems far smaller and simpler than previously imagined. The pulse reactors described in this work utilise readily available components and so can be assembled, operated, and maintained with minimal training. Using the case study of CO oxidation over a Pt/SiO2 catalyst we show that precise kinetic, mechanistic, and surface composition information is feasible using our single-valve design. With the developments outlined in this work we aim to decrease the activation barrier to TAP and open up the technique to a new generation of researchers.
The study of quadruple bonds between transition metals, in particular those of dimolybdenum, has revealed much about the two-electron bond. The solid-state structure of the quadruple-bonded dimolybdenum(II) complex tetrakis(μ-4-trifluoromethylbenzoato-κ2 O:O′)dimolybdenum(II) 0.762-pentane 0.238-tetrahydrofuran solvate, [Mo2(p-O2CC6H4CF3)4·2THF]·0.762C5H12·0.238C4H8O or [Mo2(C8H4F3O2)4(C4H8O)2]·0.762C5H12·0.238C4H8O is reported. The complex crystallizes within a triclinic cell and low symmetry (P\overline{1}) results from the intercalated pentane/THF solvent molecules. The paddlewheel structure at 100 K has inversion symmetry and comprises four bridging carboxylate ligands encases the Mo2(II,II) core that is characterized by two axially coordinated THF molecules and an Mo—Mo distance of 2.1098 (7) Å.
Liquid−liquid phase separation (LLPS) of atmospheric particles impacts a range of atmospheric processes. Driven by thermodynamics, LLPS occurs in mixed organic−inorganic particles when high inorganic salt concentrations exclude organic compounds, which develop into a separate phase. The effect of particle size on the thermodynamic and kinetic drivers of LLPS, however, remains incompletely understood. Here, the size dependence was studied for the separation relative humidity (SRH) of LLPS. Submicron organic−inorganic aerosol particles of ammonium sulfate mixed with 1,2,6-hexanetriol and polyethylene glycol (PEG) were studied. In a flow configuration, upstream size selection was coupled to a downstream fluorescence aerosol flow tube (F-AFT) at 293 ± 1 K. For both mixed particle types, the SRH values for submicron particle diameters of 260−410 nm agreed with previous measurements reported in the literature for supermicron particles. For smaller particles, the SRH values decreased by approximately 5% RH for diameters of 130−260 nm for PEG-sulfate particles and of 70−190 nm for hexanetriol-sulfate particles. From these observations, the nucleation rate in the hexanetriol-sulfate system was constrained, implying an activation barrier to nucleation of +1.4 to +2.0 × 10 −19 J at 70% RH and 293 K. Quantifying the activation barrier is an approach for predicting size-dependent LLPS in the atmosphere.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.