Abstract:

Electrochemical reduction of carbon dioxide (CO₂) is an effective way to achieve zero emission of carbon dioxide. CO₂ reduction reaction involves a multi-proton electron coupling transfer process, and the development of efficient electrocatalysts remains the key point. A polyaniline (PANI) modified metal-organic framework (MOF) derived electrode was prepared. PANI was deposited on the surface of carbon paper, and Cu₂O nanoparticles were loaded on the surface of PANI. The experimental results showed Cu₂O produced by the controllable pyrolysis method was the main reactive substance for the electroreduction of CO₂ to ethylene (C₂H₄). At -0.98V vs. RHE, the Faraday efficiency of ethylene could reach 38% and the current density of C₂H₄ was -8.5mA/cm². In the synthesis process, polyvinylpyrrolidone modification could construct a rich pore structure, which was beneficial for CO₂ diffusion. Cu²⁺ on the surface of PANI was converted into Cu⁺ in the annealing stage. At the same time, the strong electron groups in PANI accelerated the electron transfer process. DFT calculations showed that PANI could adjust the d-band structure of Cu₂O, which was conducive to increasing the adsorption capacity of CO₂ and promoting the C—C coupling process.

Key words: greenhouse gas, electrochemistry, reduction, nanomaterials, hydrocarbons

摘要：

电催化还原技术是一种实现二氧化碳（CO₂）净零排放的有效途径。由于CO₂还原反应（CO₂RR）涉及多质子电子耦合转移过程，需要开发高效CO₂还原催化剂。制备一种聚苯胺（PANI）改性金属有机框架（MOF）衍生电极，PANI沉积在碳纸表面，Cu₂O纳米颗粒负载在PANI表面。实验结果表明，通过可控热解方法生成的氧化亚铜是电还原CO₂为乙烯（C₂H₄）主要反应活性物质。当电压（vs. RHE）为-0.98V时，乙烯的法拉第效率可以达到38%，此时C₂H₄分电流密度为-8.5mA/cm²。在材料合成过程中，聚乙烯吡咯烷酮可以在催化剂表面构建丰富的孔道结构，有利于CO₂扩散过程。在退火阶段，PANI表面的Cu²⁺转化为Cu⁺。同时PANI中的强电子基团加速了电子传输过程。DFT计算结果表明，PANI通过调节Cu₂O的d带结构，增强CO₂在催化剂表面的吸附量，促进C—C偶联过程。

关键词: 温室气体, 电化学, 还原, 纳米材料, 碳氢化合物