超薄二维Bi/BiOx纳米片电还原CO2制甲酸的性能与机理研究

Converting CO2 to valuable industrial materials by electrochemical methode is a hot research problem recently. The traditional catalysts possess high overpotentials for electroreduction of CO2, so significant power is required to drive the reaction on them. Therefore, the development of the catalyst with high activity and its mechanism for electroreduction of CO2 is an important issue to be solved in CO2 reduction studies. This project will systematically study electroreduction of CO2 to formic acid with high efficiency. The latest research reports and our preliminary studies have confirmed that the presence of the oxide layer on the surface of Sn electrode is favorable to the electroreduction of CO2 to formic acid; some reports have also indicated that the ultrathin two-dimensional structure of Co-based catalyst is benefit to the electroreduction of CO2 to formic acid. Bi-based catalyst less to be reported, that possesses lower overpotential than traditional metal catalysts for electroreduction of CO2 to formic acid, is studied in this project. We focus on the preparation of ultrathin two-dimensional Bi/BiOx nanosheets catalyst and investigate the influence mechanisms of the “ultrathin two-dimensional” structure and the “Bi/BiOx hybrid” structure on reduction of CO2 to formic acid separately. Meanwhile, according to the Tafel diagram of CO2 reduction reaction, the kinetics and the mechanism for reduction of CO2 to formic acid on the catalysts are studied. This study will lay a solid foundation for designing and developing the catalysts for electroreduction of CO2 with high efficiency.

通过电化学法将CO2转化为有价值的工业原料是目前的研究热点，传统催化剂上电还原CO2的过电位较高从而需要大量的电能来驱动反应，因此高活性催化剂的开发及其对CO2电还原的作用机制是CO2电还原研究中亟待解决的重要课题。本项目将对如何提高电还原CO2制甲酸的效率进行系统地研究。最新的研究报道与我们的前期研究中均证实Sn电极表面氧化层的存在有利于CO2电还原制甲酸；也有报道指出Co基催化剂的超薄二维结构有利于CO2电还原制甲酸。本项目选择比传统电还原CO2制甲酸的金属催化剂过电位更低且报导较少的Bi基催化剂进行研究，拟制备超薄二维Bi/BiOx纳米片催化剂，研究“超薄二维”结构与“Bi/BiOx杂化”结构分别对CO2还原制甲酸的影响机制；同时根据电还原CO2反应的Tafel图，研究催化剂上还原CO2生成甲酸的反应动力学与机理。本项目的开展将为设计和研发高效率电还原CO2的催化剂奠定坚实的基础。

将CO2电化学转化为有价值的工业原料是目前的研究热点，传统催化剂上电还原CO2的过电位较高从而需要大量的电能来驱动反应，因此高活性催化剂的开发及其电还原CO2的作用机制是CO2电还原研究中的重要课题。本项目的目的是研究高效的催化剂用于电还原CO2制甲酸。相比于传统的电还原CO2制甲酸的金属催化剂，Bi基催化剂的过电位较低且报导较少，因此本研究分别采用电沉积法和水热法制备了一系列的Bi基纳米材料，将其作为阴极催化剂用于电化学还原CO2制甲酸盐。所制备的Bi基催化剂在保证法拉第效率不降低的同时，通过降低阴极反应的过电位进而提高了能量效率。同时我们研究了Bi基催化剂的形貌和结构对其电化学性能的影响，探索了催化剂上电还原CO2制甲酸盐的反应机理。为了进一步地提高能量效率，我们还对阳极催化剂进行了研究，通过降低阳极析氧反应的过电位，进而降低电化学还原CO2制甲酸盐的整个反应的过电位。本项目为设计和研发高效率电还原CO2的催化剂奠定了坚实的基础。