Single-atom catalysts (SACs) have emerged as an excellent platform for enhancing catalytic performance. Inspired by the recent experimental synthesis of nitrogenated holey 2D graphene (C2N-h2D) (Mahmood et al., Nat. Commun., 2015, 6, 6486-6493), we report density functional theory calculations combined with computational hydrogen electrode model to show that C2N-h2D supported metal single atoms (M@C2N) are promising electrocatalysts for CO2 reduction reaction (CO2 RR). M confined at pyridinic N6 cavity promotes activation of inert O[double bond, length as m-dash]C[double bond, length as m-dash]O bonds and subsequent protonation steps, with *COOH → *CO → CHO predicted to be the primary pathway for producing methanol and methane. It is found that *CO + H+ + e- → *CHO is most likely to be the potential determining step; breaking the scaling relation of *CO and *CHO binding on M@C2N SACs may simply be a rare event that is sensitively controlled by the detailed geometry of the adsorbate. Among twelve metals screened, M@C2N SACs where M = Ti, Mn, Fe, Co, Ni, Ru were identified to be effective in catalyzing CO2 RR with lowered overpotentials (0.58 V-0.80 V).
Small means big: DFT-calculated C–O bond length of adsorbed intermediates can serve as a good descriptor for predicting the C–O bond scission reactivity of phenolics over metal catalysts.
For many years, experimental and theoretical studies have investigated the solubility of CO2 in a variety of ionic liquids (ILs), but the overarching absorption mechanism is still unclear. Currently, two...
Ionic liquids (ILs) are known to have tunable solvation properties, based on the pairing of different anions and cations, but the compositional landscape is vast and challenging to navigate efficiently. Some computational screening protocols are available, but they can be either time-consuming or difficult to implement. Herein, we perform a detailed investigation of the fundamental role of electrostatic interactions in these systems. We effectively develop a bridge between the previous volume-based approach with a quantum structure−property relationship approach to create fast, simple screening guidelines. We propose a new parameter that is applicable to both monovalent and multivalent ions, the ionic polarity index (IPI), which is defined as the ratio of the average electrostatic surface potential (V̅ ) of the ion to the net charge of the ion (q). The IPI correlation has been tested on a diverse data set of 121 ions, and reliable predictions can be obtained within a homologous series of IL compounds.
Conversion of epichlorohydrin to glycidyl ethers creates versatile precursors that can be transformed into a variety of molecular species with glycerol skeletons, enabling the design of molecules with highly tailored functionalities. The synthesis of 2,2,2-trifluoroethyl glycidyl ether (TFGE, IUPAC name: 2-[(2,2,2-trifluoroethoxy) methyl]oxirane, CAS# 1535-91-7) was optimized to provide high yield/selectivity and good "green metrics." TFGE was then used as a platform molecule in the synthesis of asymmetric glycerol 1,3-diether-2-alcohol derivatives, which were subsequently transformed to 1,2,3-triethers or 1,3-diether-2-ketones. The density, viscosity, and CO 2 solubility of each molecule were measured and compared with those of other glycerol-derived compounds as well as compounds with similar functional groups. Furthermore, quantum chemical calculations were performed to understand the structure-property-performance relationships of these molecules for CO 2 absorption. Based on the results in this work, we foresee that TFGE (and similar glycidyl ethers) would offer great flexibility in molecular design of green solvents and precursors to more complex compounds.
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