Theoretical model of biomacromolecule through nanopore including effects of electrolyte and excluded volume

A theoretical model for the translocation process of biomacromolecule is developed based on the self-consistent field theory （SCFT）, where the biomacromolecule is regarded as a self-avoiding polymer chain actuated by the external potential. In this theoretical model, the external potential, the Coulomb electrostatic potential of the charged ions （the electrolyte effect）, and the attractive interaction between the polymer and the nanopore （the excluded volume effect） are all considered, which have effects on the free energy landscape and conformation entropy during the translocation stage. The result shows that the entropy barrier of the polymer in the solution with high valence electrolyte is much larger than that with low valence electrolyte under the same condition, leading to that the translocation time of the DNA molecules in the solution increases when the valence electrolyte increases. In addition, the attractive interaction between the polymer and the nanopore increases the free energy of the polymer, which means that the probability of the translocation through the nanopore increases. The average translocation time decreases when the excluded volume effect parameter increases. The electrolyte effect can prolong the average translocation time. The simulation results agree well with the available experimental results.

Physical Diffusion and Electron-transfer Dynamics of Electroactive Solutes in Polymer Electrolytes Ⅱ. Effect of the Ionic Size of Supporting Electrolytes

The ditheion coefficients(Dapp) and the heterogeneous electron-transfer rate constan(ks)for ferrocene in MPEG/salt electrolytes were determined by using Steady-stae voltammetry. The temperature dependence of the two parameters obeys the Arrhenius equstion. The effect of the ionic size of sir supporting electrolytes on diffusion and electron transfer dynamics of fermcene was discussed

CO_(2)electrolysis:Advances and challenges in electrocatalyst engineering and reactor design

Electrochemical reduction of CO_(2)(CO_(2)RR)coupled with renewable electrical energy is an attractive way of upgrading CO_(2)to value-added chemicals and closing the carbon cycle.However,CO_(2)RR electrocatalysts still suffer from high overpotential,and the complex reaction pathways of CO_(2)RR often lead to mixed products.Early research focuses on tuning the binding of reaction intermediates on electrocatalysts,and recent efforts have revealed that the design of electrolysis reactors is equally important for efficient and selective CO_(2)RR.In this review,we present an overview of recent advances and challenges toward achieving high activity and high selectivity in CO_(2)RR at ambient conditions,with a particular focus on the progress of CO_(2)RR electrocatalyst engineering and reactor design.Our discussion begins with three types of electrocatalysts for CO_(2)RR(noble metalbased,none-noble metal-based,and metal-free electrocatalysts),and then we examine systems-level strategies toward engineering specific components of the electrolyzer,including gas diffusion electrodes,electrolytes,and polymer electrolyte membranes.We close with future perspectives on catalyst development,in-situ/operando characterization,and electrolyzer performance evaluation in CO_(2)RR studies.

High-performance Zn battery with transition metal ions co-regulated electrolytic MnO_(2)

Electrolytic MnO_(2)/Zn batteries have attracted extensive attention for use in large-scale energy storage applications due to their low cost,high output voltage,safety,and environmental friendliness.However,the poor electrical conductivity of MnO_(2)limits its deposition and dissolution at large capacities,which leads to sluggish reaction kinetics and drastic capacity decay.Here,we report a theory-guided design principle for an electrolytic MnO_(2)/Zn battery co-regulated with transition metal ions that has improved electrochemical performance in terms of deposition and stripping chemistries.We start with first-principles calculations to predict the electrolytic effects of regulating transition metal ions in the deposition/stripping chemistry of the MnO_(2)cathode.The results indicate that with the simultaneous incorporation of strongly electronegative Co and Ni,the MnO_(2)cathode tends to possess more active electron states,faster charge-transfer kinetics,and better electrical conductivity than either MnO_(2)regulated with Co or Ni on their own,or pristine MnO_(2);hence,this co-regulation is beneficial for the cathode solid/liquid MnO_(2)/Mn2t reactions.We then fabricate and demonstrate a novel Co2t and Ni2t coregulated MnO_(2)/Zn(Co-Ni-MnO_(2)/Zn)battery that yields significantly better electrochemical performance,finding that the synergistic regulation of Co and Ni on MnO_(2)can significantly increase its intrinsic conductivity and achieve high rates and Coulombic efficiencies at large capacities.The aqueous Co-Ni-MnO_(2)/Zn battery exhibits a high rate(10C,100 mA cm^(-2)),high Coulombic efficiency(91.89%),and excellent cycling stability(600 cycles without decay)at a large areal capacity of 10 mAh cm^(-2).Our proposed strategy of co-regulation with transition metal ions offers a versatile approach for improving the electrochemical performance of aqueous electrolytic MnO_(2)/Zn batteries in large-scale energy storage applications.