新颖含铜、镍金属间化合物的合成及其电催化还原二氧化碳性能研究

The level of CO2 concentration in the atmosphere has been increased gradually in the past couple decades. This results in a more and more profound greenhouse effect and causes a server climate change on global scale. Lowering the CO2 concentration is the goal for every country in the recent years. With this goal in mind, the aim of present project is to investigate the electrocatalytic CO2 reduction mechanism of copper- and nickel-based intermetallic compounds. The explored system will also include metals with high and low adsorption energy of CO to systematically study its effect toward the product of electrocatalytic CO2 reduction. In addition, we will also add metals with high overpotential of hydrogen production in the system to suppress hydrogen evolution reaction and to enhance the performance of electrocatalytic CO2 reduction. The focused binary and ternary intermetallic systems of this project are as follows: Cu－T and Ni－T (T = C，Si，Ge，Sn，Bi),Cu－M－T and Ni－M－T (M = Ti，Fe，Co; T = C，Si，Ge，Sn，Bi),Cu－N－T and Ni－N－T (N = Zn，Ga，In，Ag，Au; T = C，Si，Ge，Sn，Bi). The intermetallics from these systems will be subjected to test their electrocatalytic ability of CO2 reduction. Additionally, for the samples that exhibit unique CO2 reduction performance, we will also attempt to control their morphology with specific facets by using metal flux synthetic approach. The theoretical calculation will be carried out to further investigate and to discuss the facets-dependent mechanism of the electrocatalytic CO2 reduction of the samples.

近年来大气中的二氧化碳浓度逐年增加，温室效应与全球气候变迁也日益严重，减少二氧化碳是近年来各国努力的目标。本课题将以含铜与镍金属间化合物为出发点来探讨其电催化还原二氧化碳的能力与反应机制，研究体系以铜与镍金属为主，加入对一氧化碳吸附能力较强与较弱的金属，系统研究金属一氧化碳吸附能力对电催化二氧化碳还原的产物有何影响。加入拥有较高氢气还原过电压的金属，以抑制氢气还原的反应路径，进而提升二氧化碳还原效能。重点研究的二元与三元金属间化合物有：Cu－T与Ni－T( T = C，Si，Ge，Sn，Bi; Cu－M－T与Ni－M－T (M = Ti，Fe，Co)、Cu－N－T 与 Ni－N－T (N = Zn，Ga，In，Ag，Au)。除了测试金属间化合物的二氧化碳还原效能外，对有特别二氧化碳还原产物的样品也将以熔融金属法，控制生成不同晶面，并以理论计算为辅深入讨论并解释二氧化碳还原的机制。

本项目透过真空氩弧焊与低温合成法合成一系列含铜与含镍金属间化合物并探讨其电催化二氧化碳还原性能与产物选择性的影响，结果发现铜111晶面有助于甲烷产物的生成，110与100晶面有利于双碳产物(乙烷与乙醇)的生成，其中110晶面对乙醇有较高的选择性，DFT理论计算推测110晶面有助于稳定OCH2CH中间产物并转化成乙醇。此外本项目所合成一系列金属间化合物的晶体结构，电子结构与催化效能间有明显的构效关系，可借由改变活性中心的晶体结构(键长)与电子结构(电子云密度)来提高催化材料的稳定性与性能，其中个别金属间化合物的稳定性与效能已超过商用产品，达到工业化应用标准，此成果成功拓展固态化学在电催化领域的研究内容的应用。..根据项目计划书，各项目任务现已完成，项目执行取的较好的研究成果，共发表SCI论文9篇，其中有两篇文章被选为封面(Chem. Commun.; Inorg. Chem.)，申请中国专利2项，参加国内外会议3次，培养硕士生2名。由此项目资助的其他成果仍在准备投稿中。