The acid-catalyzed ring-opening reaction of styrene oxide was used as a probe reaction for evaluating the acidic properties of carboxylated carbocatalysts. Significant discrepancies in the initial reaction rates were normalized using the total number of carboxyl groups, and demonstrated that the average catalytic activities of the carboxyl moieties on the carbocatalysts differed. Comparisons between the apparent activation energy Ea and the pre-exponential factor A, derived from Arrhenius analysis, demonstrated that A varied more significantly, and therefore had a more significant effect on the reaction rates than Ea. The variation in the calculated pKa values of the carboxyl groups was attributed to the electronic effects of the nitro groups. This hypothesis was supported by the temperature programmed desorption profiles of nitrogen monoxide ions.
Mixed transition metal oxides (MTMOs) have received intensive attention as promising anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). In this work, we demonstrate a facile one-step water-bath method for the preparation of graphene oxide (GO) decorated Fe2(MoO4)3 (FMO) microflower composite (FMO/GO), in which the FMO is constructed by numerous nanosheets. The resulting FMO/GO exhibits excellent electrochemical performances in both LIBs and SIBs. As the anode material for LIBs, the FMO/GO delivers a high capacity of 1,220 mAh·g–1 at 200 mA·g–1 after 50 cycles and a capacity of 685 mAh·g–1 at a high current density of 10 A·g–1. As the anode material for SIBs, the FMO/GO shows an initial discharge capacity of 571 mAh·g–1 at 100 mA·g–1, maintaining a discharge capacity of 307 mAh·g–1 after 100 cycles. The promising performance is attributed to the good electrical transport from the intimate contact between FMO and graphene oxide. This work indicates that the FMO/GO composite is a promising anode for high-performance lithium and sodium storage.
