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Functional groups in two‐dimensional (2D) Ti3C2Tx MXene are an important factor influencing electrochemical performance in many applications involving energy storage, electrochemical sensors, and water purification. However, after dimethyl sulfoxide (DMSO) delamination, the effect of surface functionalities in Ti3C2Tx is still unclear and there are no systematic reports on its capacitive behavior. Experiments and theoretical calculations confirm the relationship between different surface functionalities, the DMSO delamination effect, and the electrochemical behavior of the DMSO‐delaminated Ti3C2Tx. The dominant −O and −OH terminations are attributed for surfaces delaminated by using HF [Ti3C2Tx (HF)] and LiF/HCl [Ti3C2Tx (LiF/HCl)], respectively. Theoretical results are also in agreement with experimental results in that −OH terminations are essential for the formation of a free‐standing film. Compared to non‐delaminated Ti3C2Tx (HF) (similar O/F ratios of 1.37 and 1.42), there is a significant DMSO delamination effect for Ti3C2Tx (LiF/HCl) because of different O/F ratios of 2.9 and 3.6. Additionally, the delaminated Ti3C2Tx (LiF/HCl) electrodes deliver a higher capacitance of 508 F cm−3 than that of 333 F cm−3 for the delaminated Ti3C2Tx (HF), although it exhibited lower equivalent series resistance, lower interlayer spacing, and slightly lower specific surface area. This study provides direct and systematic experimental evidence for different functional groups in Ti3C2Tx MXene based on the DMSO delamination effect. Digging your MXene: A significant delamination effect of surface functionalities in Ti3C2Tx is demonstrated experimentally and theoretically. O‐containing functional groups, morphological defect‐free, and small flake size HF‐etched MXene nanosheets are better suited for water splitting, optical electrics, and water purification. Alternatively, hydroxy groups of LiF/HCl‐etched MXene films promote effective ion permeation for energy storage and nuclear purification. [ABSTRACT FROM AUTHOR]

The inhibition effect of a Schiff base with several functional groups on the corrosion of aluminum in alkaline solution is studied by experimental techniques and density function theory (DFT) calculations. The Schiff base are characterized by 1 HNMR, 13 CNMR, FT-IR, and CHN elemental analysis. In addition, different electrochemical and corrosion techniques such as weight loss, tafel polarization, electrochemical impedance spectroscopy (EIS) and optical microscopy images are performed to analyze the inhibiting performances. In the Tafel measurements the cathodic Tafel slopes values incurred small changes with increasing the inhibitor concentration, which revealed that the inhibitor was adsorbed on the aluminum surface. The inhibition efficiencies are calculated from weight loss measurement and electrochemical tests. The adsorption of the inhibitor onto the aluminum surface follows the Langmuir adsorption isotherm with the free adsorption energy of −8.66 kJ mol −1 . The calculated adsorption energies and the amount of charge transfer obtained by DFT calculation revealed that corrosion inhibition effectively occurs with chemisorption, where new N Al bonds are formed between of N atoms in azo (–N N–) group and Al surface atoms, which is confirmed from ab initio molecular dynamics (AIMD) simulation. [ABSTRACT FROM AUTHOR]

We systematically investigated the tuning of the reduction potentials ( E 0 ) for the first row transition metal (M = Cr, Mn, Fe, Co, Ni) complexes with the functionalized 1,4,7-Triazacyclononane-N,N',N”-triacetate (TCTA) ligands by means of DFT calculations. To predict reliable E 0 , the modified UB3LYP functional and equilibrium concept between high and low spin states were utilized. The functional groups NH 2 , CN, −F, and NO 2 were attached to the carbon atoms carefully selected by considering the LUMO and steric hindrance. Based on firmed accuracy of DFT calculations, finally we obtained the calculated E 0 for a series of complexes. It was found that electron donating group such as NH 2 will cause a negative shift of E 0 while electron withdrawing groups have the opposite effect. The overall trend of the calculated E 0 s according to ligand modifications were predicted to have the order as −NH 2 < Pristine < −F ≈ −CN < −NO 2 . In addition, optimized geometries, LUMO, vertical electron attachment and energy components constituting E 0 were discussed in detail to assist the further understanding for E 0 s. Consequently, we suggested that 16 complexes can play a role as an electrolyte in aqueous redox flow battery. They can be classified into 5 groups having similar E 0 ranges: Group I (- 0.6 V ∼ − 0.7 V), Group II (around 0.0 V), Group III (around 0.3 V), Group IV (0.6 ∼ 0.8 V) and Group V (1.1 ∼ 1.2 V). Especially, it is expected that [MnL F ] , [MnL CN ] and [NiL NH2 ] can be used as promising catholyte candidates possibly possessing high E 0 s which almost reach to the reduction potential limitation 1.25 V in aqueous redox flow battery. Our systematic approach to tune E 0 can be applied to the design of other complexes via rational ligand modification. [ABSTRACT FROM AUTHOR]

Abstract: A series of blue fluorescent 9,9-diethyl-2,7-distyryl-9H-fluorene derivatives with various capping moieties such as diphenylamino; diphenylphosphino; triphenylsilyl; phenoxy; phenylmercapto; phenylselenoxy; and triphenymethyl groups were synthesized using the Honor–Emmons reaction. The highest occupied molecular orbital-lowest unoccupied molecular orbital energy levels were characterized with a photoelectron spectrometer and rationalized with quantum mechanical density functional theory calculations. The electroluminescent properties were explored through the fabrication of multilayer devices with a structure of Indium-tin-oxide/N,N′-diphenyl-N,N′-(1-napthyl)-(1,1′-phenyl)-4,4′-diamine/2-methyl-9,10-di(2-naphthyl)anthracene:blue dopants (5–15wt.%)/4,7-diphenyl-1,10-phenanthroline/lithium quinolate/Al. All devices, except that using NPh2, exhibited a Commission Internationale de I''Eclairage (CIE) y value less than 0.19. The best luminous efficiency of 3.87cd/A and external quantum efficiency of 2.65% at 20mA/cm2 were obtained in a device comprising the 4-phenylsulfanyl capped 9,9-diethyl-2,7-distyrylfluorene derivative with CIE coordinates (0.16, 0.18). [Copyright &y& Elsevier]