磷化钴-泡沫钴自支撑电极电化学还原溴酸盐

开发活性高和价格低廉的电极材料是溴酸盐(${rm{BrO}}_3^ - $)电化学还原技术的关键。贵金属电极因其高活性受到广泛关注,但贵金属储量低且价格昂贵导致其推广应用受限。为此,本研究在不使用粘结剂的情况下,通过直接在高温条件下将磷化泡沫钴原位生长转化为磷化钴,从而制备出磷化钴-泡沫钴自支撑电极(CoP/CF),并将其用于电化学还原${rm{BrO}}_3^ - $。结果表明：350 ℃下磷化制备的电极CoP/CF-350性能最优;当${rm{BrO}}_3^ - $初始质量浓度为250 μg·L⁻¹、电流密度为5.0 mA·cm⁻²时,该电极对${rm{BrO}}_3^ - $去除率为97.6%,相应的能耗为0.014 kWh·mg⁻¹。循环伏安测试(CV)和淬灭实验结果表明,${rm{BrO}}_3^ - $的去除归因于直接电子传递和活性氢(H^*)间接还原的协同作用。原位生长的CoP作为双功能催化剂,起到了电子传递媒介和桥梁的作用,强化了${rm{BrO}}_3^ - $的还原。经过5次循环实验后,CoP/CF-350电极仍保持良好电催化活性,说明其具有良好的稳定性。

Efficient electrochemical bromate reduction using cobalt phosphide self-supported cobalt foam electrode

Exploring highly active and inexpensive electrode are the keys in electrochemical reduction of bromate (${rm{BrO}}_3^ - $). Although the noble metal-based electrode has attracted intensive attention for its high activity, low abundance and high price of noble metal seriously impede its practical application. In this study, a binder-free composite electrode (CoP/CF) was prepared by direct growth of cobalt phosphide(CoP) on cobalt foam(CF) and then was used to perform electrochemical reduction of ${rm{BrO}}_3^ - $. The results showed that CoP/CF-350 electrode prepared at 350 ℃ had a better electrochemical performance on high ${rm{BrO}}_3^ - $ reduction(97.6%) and lower energy consumption (0.014 kWh·mg−1) at the initial ${rm{BrO}}_3^ - $ concentration of 250 μg·L−1 and current density of 5.0 mA·cm−2. The cyclic voltammetry(CV) and quenching experiments demonstrated that ${rm{BrO}}_3^ - $ removal should be ascribed to the synergistic effect of direct electron transfer and active hydrogen (H*) indirect reduction. The in-situ grown CoP served as the bifunctional catalyst and played the dual roles of electron mediator and bridge, further enhanced the ${rm{BrO}}_3^ - $ reduction. Even after five cyclic experiments, the CoP/CF-350 electrode still remained a good electrocatalytic activity, this indicated that this electrode had a good stability.