anode because of the sluggish reaction kinetics and high barrier for the formation of OO bond. [6,7] Noble metalbased catalysts such as IrO 2 and RuO 2 exhibit excellent OER activity, but their high cost and non-renewability limit the wide-spread applications. [8][9][10][11] Therefore, it is of great importance to develop costeffective and stable non-noble metalbased electrocatalysts. [12][13][14][15][16][17][18] Metal-organic frameworks (MOFs), with highly dispersed metal sites, intrinsic high porosity, and high internal surface area, have been considered as potential non-noble metal-based catalysts for OER. [19][20][21][22][23] Among the various MOFsbased OER catalysts, Co-based MOFs have received extensive attention due to the high activity and stability. [24,25] More importantly, the structural flexibility of most Co-based MOFs allows the design and fabrication of bimetallic MOFs with different second metal, leading to higher catalytic performance. [26][27][28][29][30][31][32] For example, Li et al. reported that the CoZn bimetallic MOFs could exhibit OER activity with the overpotential of 320 mV at a current density of 10 mA cm −2 due to dimensionality and pore-geometry. [33] Furthermore, Bu et al. reported that the CoNi bimetallic 2D-MOFs exhibited excellent OER activity with the overpotential of 240 mV at 10 mA cm −2 , thanks to the CoNi coupling effect and the unsaturated active sites. [34] However, although plenty of efficient Co MOFs-based bimetallic OER catalysts have been developed, to the best of our knowledge, the effect of different second metal on the OER catalytic performance of Co-based MOFs has not been systematically investigated. What is worse, it is inappropriate to compare the results in reported works directly, because the reported Co-based MOFs may be different in coordination environment, dimension, and amount of second metal.Herein, we introduce different metal (M = Ni, Cu, Zn) into typical Co MOFs (i.e., ZIF-67) and further study their catalytic performance for OER in alkaline media to uncover the secondmetal effect for Co MOFs. These MOFs were grown on conductive carbon cloth (CC) immediately through a one-step roomtemperature strategy (marked as CoM MOFs/CC). [35] The order of OER activity, which is reflected by overpotential and Tafel slope, for these Co-based MOFs is found to be CoZn MOF/CC > CoNi MOF/CC > CoCu MOF/CC > Co MOF/CC. Furthermore, by Co-based bimetallic metal-organic frameworks (MOFs) have emerged as a kind of promising electrocatalyst for oxygen evolution reaction (OER). However, most of present works forCo-based bimetallic MOFs are still in try-and-wrong stage, while the OER performance trend and the underlying structure-function relationship remain unclear. To address this challenge, Cobased MOFs on carbon cloth (CC) (CoM MOFs/CC, M = Zn, Ni, and Cu) are prepared through a room-temperature method, and their structure and OER performance are compared systematically. Based on the results of overpotential and Tafel slope, the order of OER activity is ordered in the de...

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A theoretical study of the chemisorption and dissociation pathways of water on the Al₁₃ cluster was performed using the hybrid density functional B3LYP method with the 6-311+G(d, p) basis set. The activation energies, reaction enthalpies, and Gibbs free energy of activation for the reaction were determined. Calculations revealed that the H₂O molecule is easily adsorbed onto the Al13 surface, forming adlayers. The dissociation of the first H₂O molecule from the bimolecular H₂O structure via the Grotthuss mechanism is the most kinetically favorable among the five potential pathways for O-H bond breaking. The elimination of H₂ in the reaction of an H₂O molecule with a hydrogen atom on the Al cluster via the Eley-Rideal mechanism has a lower activation barrier than the elimination of H₂ in the reaction of two adsorbed H atoms or the reaction of OH and H. Following the adsorption and dissociation of H₂O, the structure of Al₁₃ is distorted to varying degrees.

2-(4-Aminophenyl)-5-aminopyrimidine (4) is synthesized via a condensation reaction of vinamidium salts and amidine chloride salts, followed by hydrazine palladium catalyzed reduction. A series of novel homo-and copolyimides containing pyrimidine unit are prepared from the diamine and 1,4-phenylenediamine (PDA) with pyromellitic dianhydride (PMDA) or 3,3 0 ,4,4 0 -biphenyl tertracarboxylic dianhydride (BPDA) via a conventional two-step thermal imidization method. The poly(amic acid) precursors had inherent viscosities of 0.97-4.38 dL/g (c ¼ 0.5 g/dL, in DMAc, 308C) and all of them could be cast and thermally converted into flexible and tough polyimide films. All of the polyimides showed excellent thermal stability and mechanical properties. The glass transition temperatures of the resulting polyimides are in the range of 307-4348C and the 10% weight loss temperature is in the range of 556-6098C under air. The polyimide films possess strength at break in the range of 185-271 MPa, elongations at break in the range of 6.8-51%, and tensile modulus in the range of 3.5-6.46 GPa. The polymer films are insoluble in common organic solvents, exhibiting high chemical resistance.

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