Theoretical simulations on complex electrochemical processes have been developed on the basis of the understanding in electrochemistry,which has benefited from quantum mechanics calculations.This article reviews the recent progress on the theory and applications in electrocatalysis.Two representative reactions,namely water electrolysis and oxygen reduction,are selected to illustrate how the theoretical methods are applied to electrocatalytic reactions.The microscopic nature of these electrochemical reactions under the applied potentials is described and the understanding of the reactions is summarized.The thermodynamics and kinetics of the electrochemical reactions affected by the interplay of the electrochemical potential,the bonding strength and the local surface structure are addressed at the atomic level.
Activated by methylaluminoxane, mononuclear bis(hydroxyindanone-iminate)nickel complexes Ni[ArN == CC_2H_3(CH3)C_6H_2(R)O]_2 (Ar = 2,6-i-Pr2C6H3, R = Me (1), R = Cl (2), and R = H (3)) showed good activity for the styrene polymerization. The effect of many reaction parameters including the Al/Ni ratio, tempera- ture, and reaction time on catalytic activities of catalytic systems and the molecular weights of the ob- tained polystyrene was ascertained. The highest activity of 1.34×105 g(PS)·mol^(-1)(Ni)·h^(-1) was obtained under the optimum reaction condition. The 13C NMR spectra of the polymers revealed that the polymer was isotactic-rich atactic polystyrene. And the coordination mechanism was confirmed by the analyses of the polymer chain end-groups.
Porous carbon nitride(CN)spheres with partially crystalline frameworks have been successfully synthesized via a nanocasting approach by using spherical mesoporous cellular silica foams(MCFs)as a hard template,and ethylenediamine and carbon tetrachloride as precursors.The resulting spherical CN materials have uniform diameters of ca.4μm,hierarchical three-dimensional(3-D)mesostructures with small and large mesopores with pore diameters centered at ca.4.0 and 43 nm,respectively,a relatively high BET surface area of~550 m^(2)/g,and a pore volume of 0.90 cm^(3)/g.High-resolution transmission electron microscope(HRTEM)images,wide-angle X-ray diffraction(XRD)patterns,and Raman spectra demonstrate that the porous CN material has a partly graphitized structure.In addition,elemental analyses,X-ray photoelectron spectra(XPS),Fourier transform infrared spectra(FT-IR),and CO_(2) temperature-programmed desorption(CO_(2)-TPD)show that the material has a high nitrogen content(17.8 wt%)with nitrogen-containing groups and abundant basic sites.The hierarchical porous CN spheres have excellent CO_(2) capture properties with a capacity of 2.90 mmol/g at 25℃and 0.97 mmol/g at 75℃,superior to those of the pure carbon materials with analogous mesostructures.This can be mainly attributed to the abundant nitrogen-containing basic groups,hierarchical mesostructure,relatively high BET surface area and stable framework.Furthermore,the presence of a large number of micropores and small mesopores also enhance the CO_(2) capture performance,owing to the capillary condensation effect.
Qiang LiJianping YangDan FengZhangxiong WuQingling WuSung Soo ParkChang-Sik HaDongyuan Zhao
