镍高度分散在铁基钙钛矿用于高温固体氧化物电解池阴极的CO2电催化还原研究(英文)

利用太阳能、风能等可再生清洁电能将CO₂催化转化为高附加值化学品或燃料,在CO₂转化和可再生电能存储方面表现出极具潜力的应用前景.高温固体氧化物电解池(SOEC)可将CO₂电催化还原为CO,具有能量效率高、成本低等优点.目前,钙钛矿氧化物已被广泛应用于SOEC电解CO₂的阴极材料,但存在电极催化活性低等问题,因而限制其规模化发展和应用.通常采用浸渍、原位溶出或掺杂等策略引入大量活性中心以提升钙钛矿氧化物电极性能.然而,这些策略仍然面临一些挑战,如浸渍法易引入大颗粒物种而堵塞气体传输通道,原位溶出法能耗较大且析出量较少,掺杂法调控活性幅度有限.因此,发展新型简便方法以合理构建具有高度分散活性位点的阴极材料,可有效拓展电化学三相反应界面,进而加快SOEC高温电解CO₂的电极动力学速率.本文采用机械研磨法将1.0%NiO高度分散于La_0.8Sr_0.2Fe0_3-δ-Ce_0.8Sm_0.2     

固体氧化物电解池

固体氧化物电解池（SOEC）是一种先进的电化学能量转化装置,可利用清洁一次能源产生的电能和热能,以H₂O和/或CO₂为原料,高效电解制备氢气或碳氢燃料,有望实现大规模能量高效转化和存储。该技术具有高效、简单、灵活、环境友好等特点,是目前国际能源领域的研究热点。本文就固体氧化电解池技术原理、关键材料、电堆技术、衰减控制和经济竞争力等方面进行分析和介绍,并对其应用前景进行展望。     

氧分压对固体氧化物电解池性能的影响

High-temperature (700–900 ℃) steam electrolysis based on solid oxide electrolysis cells (SOECs) is valuable as an efficient and clean path for large-scale hydrogen production with nearly zero carbon emissions, compared with the traditional paths of steam methane reforming or coal gasification. The operation parameters, in particular the feeding gas composition and pressure, significantly affect the performance of the electrolysis cell. In this study, a computational fluid dynamics model of an SOEC is built to predict the electrochemical performance of the cell with different sweep gases on the oxygen electrode. Sweep gases with different oxygen partial pressures between 1.01 × 10³ and 1.0 × 10⁵ Pa are fed to the oxygen electrode of the cell, and the influence of the oxygen partial pressure on the chemical equilibrium and kinetic reactions of the SOECs is analyzed. It is shown that the rate of increase of the reversible potential is inversely proportional to the oxygen partial pressure. Regarding the overpotentials caused by the ohmic, activation, and concentration polarization, the results vary with the reversible potential. The Ohmic overpotential is constant under different operating conditions. The activation and concentration overpotentials at the hydrogen electrode are also steady over the entire oxygen partial pressure range. The oxygen partial pressure has the largest effect on the activation and concentration overpotentials on the oxygen electrode side, both of which decrease sharply with increasing oxygen partial pressure. Owing to the combined effects of the reversible potential and polarization overpotentials, the total electrolysis voltage is nonlinear. At low current density, the electrolysis cell shows better performance at low oxygen partial pressure, whereas the performance improves with increasing oxygen partial pressure at high current density. Thus, at low current density, the best sweep gas should be an oxygen-deficient gas such as nitrogen, CO₂, or steam. Steam is the most promising because it is easy to separate the steam from the by-product oxygen in the tail gas, provided that the oxygen electrode is humidity-tolerant. However, at high current density, it is best to use pure oxygen as the sweep gas to reduce the electric energy consumption in the steam electrolysis process. The effects of the oxygen partial pressure on the power density and coefficient of performance of the SOEC are also discussed. At low current density, the electrical power demand is constant, and the efficiency decreases with growing oxygen partial pressure, whereas at high current density, the electrical power demand drops, and the efficiency increases.     

高温固体氧化物电解制氢技术

高温水蒸气电解制氢是解决大规模氢源问题的潜在途径之一。高温固体氧化物电解池（SOEC）可以利用各种可再生能源以及先进核能提供的热能和电能,在高温下将水蒸气高效电解为氢气和氧气。SOEC结合先进核能可以实现高达50%的热氢转化效率,已经成为近年来能源领域的一个研究热点。本文较详细介绍了SOEC的原理、分类、组成材料和特点,综述了SOEC制氢的发展现状、关键材料和核心技术,展望了SOEC在先进能源技术领域的应用前景。     

氧离子传导型固体氧化物电解池燃料电极的研究进展

固体氧化物电解池可高效地电解H₂O/CO₂制备燃料,越来越受到人们的重视. 本文对近年来在燃料电极（阴极）材料方面的研究进展进行了全面综述,指出各种阴极材料的优缺点及发展趋势,强调亟待解决的关键科学与技术问题.     

阴极支撑Ni-YSZ/YSZ/LSM-YSZ固体氧化物电解池制氢性能研究

利用固体氧化物电解池(Solid oxide electrolysis cell,SOEC)在高温下电解水蒸气制氢,被认为是未来的大规模制氢方法之一.本文采用干压法和丝网印刷法制备了SOEC,考察了氢电极气氛和工作温度对SOEC电解性能的影响,测试了SOEC的稳定性.实验结果表明:氢电极进气中适宜的水蒸气含量为70%～80%;电解池在800,850和900℃,1.50 V的产氢速率分别为89,163和243 N·ml·cm-2·h-1;在900℃以0.33 A·cm-2恒流电解2 h,电解电压的稳定值为0.98 V,并且电解池运行稳定,无明显衰减.阻抗谱解析表明,电极过程是整个电解池电极反应的速度控制步骤.     

中低温固体氧化物燃料电池阴极材料

固体氧化物燃料电池(SOFCs)作为一种高效的能量转化装置,其成功应用将有效地节约能源和降低能源利用过程中环境污染物的排放,对人类社会的可持续发展意义重大.低温化可加快SOFCs商品化的步伐,而其关键在于开发高性能的阴极材料.本论文对近年来在中低温SOFCs阴极材料方面的研究进展进行了较全面的综述,其中包括Ba0.5S...     

高温固体氧化物电解制氢技术发展现状与展望

固体氧化物电解池是一种先进的能量转换装置,具有高效、简单、灵活、环境友好等特点,是目前国际能源领域的研究热点. 本文对高温固体氧化物电解制氢技术的基本原理、关键材料、系统组成、发展历程及国内外研究现状等进行了总结和分析,小结了该技术发展面临的主要挑战,简述了清华大学在高温固体氧化物电解领域近期的研究进展,并对其未来应用前景进行了展望.     

单体固体氧化物电解池极化损失分析及阴极微结构优化

基于高温固体氧化物电解池(SOEC)的高温蒸汽电解(HTSE)制氢技术作为一种非常有前景的大规模核能制氢新方法, 受到国际上的迅速关注. 但如何控制电解模式下的极化能量损失和性能衰减是HTSE实用化的关键. 本文通过在线电化学阻抗测试技术, 研究了实际运行状态下的单体固体氧化物池(SOC)在电池模式和电解模式下的极化阻抗分布, 阐述了SOEC与高温固体氧化物燃料电池(SOFC)的差异, 确定了SOEC氢电极支撑层水蒸气扩散过程极化损失大是制约电解池制氢性能提高的主要因素. 在此基础上, 采用聚甲基丙烯酸甲酯(PMMA)造孔剂对氢电极支撑层的微观结构进行了调整和优化. 微结构优化后, 氢电极材料的孔隙率提高了50%, 孔隙为规则圆形, 分布均匀, 更利于气体扩散; 电解电压1.3 V时, 单位面积产氢率高达328.1 mL·cm^-2·h^-1(标准态), 为改进前电解池的2倍, 实现50 h以上连续稳定性运行. 研究成果可为HTSE的实际应用提供一定的理论数据和技术基础.     

高温固体氧化物电解池钙钛矿型氧电极材料Ba_xSr_(1-x)Co_(0.8)Fe_(0.2)O_(3-δ)结构计算与性能研究

研究和开发高性能的钙钛矿型混合电导氧化物是目前高温固体氧化物电解池(SOEC)氧电极材料研究的热点.选择BaxSr1-xCo0.8Fe0.2O3-δ系列材料,通过对材料的容差因子、关口半径、晶格自由体积等计算,以及对平均键能、B位离子的变价能力、催化活性等方面的分析,确定了A位最佳配比.对优化出的Ba0.5Sr0.5Co0.8Fe0.2O3-δ材料的电化学性能进行了研究,并与自制的La0.2Sr0.8MnO3(LSM)氧电极材料进行了比较.结果表明:850℃下阳极极化阻抗(ASR)仅为0.07Ωcm2,远低于LSM;将其应用于SOEC氧电极进行高温电解制氢试验,产氢速率为相同条件下LSM的2.3倍,说明将Ba0.5Sr0.5Co0.8Fe0.2O3-δ用作SOEC阳极材料具有很好的应用前景.     

An Aurivillius Oxide Based Cathode with Excellent CO2 Tolerance for Intermediate‐Temperature Solid Oxide Fuel Cells

The Aurivillius oxide Bi₂Sr₂Nb₂MnO_12?δ (BSNM) was used as a cobalt‐free cathode for intermediate‐temperature solid oxide fuel cells (IT‐SOFCs). To the best of our knowledge, the BSNM oxide is the only alkaline‐earth‐containing cathode material with complete CO₂ tolerance that has been reported thus far. BSNM not only shows favorable activity in the oxygen reduction reaction (ORR) at intermediate temperatures but also exhibits a low thermal expansion coefficient, excellent structural stability, and good chemical compatibility with the electrolyte. These features highlight the potential of the new BSNM material as a highly promising cathode material for IT‐SOFCs.     

铋基二氧化碳还原电催化材料研究进展

二氧化碳（CO₂）作为一种经济、安全、可再生的碳资源化合物,其高效回收利用一直是全社会关注的焦点. 利用电化学方法,将CO₂还原转化生成一系列高附加值的化学品或燃料,对于缓解能源与环境双重压力具有重要的现实意义. 本论文介绍了电化学CO₂还原反应的基本原理与过程,综述了近年来铋基催化材料的发展现状,重点对这类催化材料的制备合成、结构调控、催化反应机理研究等方面进行了总结,最后对其未来发展方向进行了探讨与展望.     

面向CO2电化学转化的铜基催化剂研究进展

Burning of fossil fuels increases CO₂ concentration in the atmosphere, resulting in a series of climate- and environment-related concerns such as global warming, sea-level rise, and melting of glaciers. Therefore, utilization of renewable energy to reduce the CO₂ concentration, in order to realize a sustainable development, is urgent. Capturing and utilizing CO₂, a greenhouse gas, can not only address these concerns but also alleviate the current scenario of energy shortage. Thermal catalytic CO₂ hydrogenation offers various pathways with high conversion efficiencies to produce fuels and industrial chemicals including CO, HCOOH, CH₃OH, and CH₄. However, CO₂ is chemically inert due to the highly stable C＝O bond. Thus, harsh reaction conditions such as high temperature and pressure are required for CO₂ hydrogenation.     

Achieving High Efficiency and Eliminating Degradation in Solid Oxide Electrochemical Cells Using High Oxygen‐Capacity Perovskite

Recently, there have been efforts to use clean and renewable energy because of finite fossil fuels and environmental problems. Owing to the site‐specific and weather‐dependent characteristics of the renewable energy supply, solid oxide electrolysis cells (SOECs) have received considerable attention to store energy as hydrogen. Conventional SOECs use Ni‐YSZ (yttria‐stabilized zirconia) and LSM (strontium‐doped lanthanum manganites)‐YSZ as electrodes. These electrodes, however, suffer from redox‐instability and coarsening of the Ni electrode along with delamination of the LSM electrode during steam electrolysis. In this study, we successfully design and fabricate highly efficient SOECs using layered perovskites, PrBaMn₂O_5+δ (PBM) and PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δ (PBSCF50), as both electrodes for the first time. The SOEC with layered perovskites as both‐side electrodes shows outstanding performance, reversible cycling, and remarkable stability over 600 hours.     

高温固体氧化物燃料电池（SOFC）进展

固体氧化物燃料电池(SOFC) 采用的是全固体的电池结构, 不存在液体电解质带来的腐蚀和流失等问题, 而且具有燃料适应性广等突出优点, 近几年发展非常迅速, 已经展示出作为集中或分散发电新技术的前景。本文较详细地介绍了固体氧化物燃料电池的特点、工作原理和关键电池材料的研制, 并全面阐述了国内外发展现状和发展趋势。     

Electrolyte Effects on the Electrochemical Reduction of CO2

The electrochemical reduction of CO₂ to fuels or commodity chemicals is a reaction of high interest for closing the anthropogenic carbon cycle. The role of the electrolyte is of particular interest, as the interplay between the electrocatalytic surface and the electrolyte plays an important role in determining the outcome of the CO₂ reduction reaction. Therefore, insights on electrolyte effects on the electrochemical reduction of CO₂ are pivotal in designing electrochemical devices that are able to efficiently and selectively convert CO₂ into valuable products. Here, we provide an overview of recently obtained insights on electrolyte effects and we discuss how these insights can be used as design parameters for the construction of new electrocatalytic systems.     

Oxygen Vacancies in ZnO Nanosheets Enhance CO2 Electrochemical Reduction to CO

As electron transfer to CO₂ is generally considered to be the critical step during the activation of CO₂, it is important to develop approaches to engineer the electronic properties of catalysts to improve their performance in CO₂ electrochemical reduction. Herein, we developed an efficient strategy to facilitate CO₂ activation by introducing oxygen vacancies into electrocatalysts with electronic‐rich surface. ZnO nanosheets rich in oxygen vacancies exhibited a current density of ?16.1 mA cm^?2 with a Faradaic efficiency of 83 % for CO production. Based on density functional theory (DFT) calculations, the introduction of oxygen vacancies increased the charge density of ZnO around the valence band maximum, resulting in the enhanced activation of CO₂. Mechanistic studies further revealed that the enhancement of CO production by introducing oxygen vacancies into ZnO nanosheets originated from the increased binding strength of CO₂ and the eased CO₂ activation.     

氧化铟基纳米催化剂用于二氧化碳选择性加氢的研究进展

二氧化碳选择性加氢反应不仅能减少二氧化碳排放, 而且能够制备多种含碳产物, 可以作为生产高附加价值化学品与燃料的平台化合物. 然而, 由于二氧化碳的高化学惰性、 碳-碳偶联过程的高能垒和诸多的竞争反应, 开发高效的纳米催化剂以促进二氧化碳的活化并转化为多样性的产物显得至关重要. 最近, 基于氧化铟的纳米催化剂在催化二氧化碳加氢方面受到广泛关注, 主要由于其成本低廉, 且具有丰富的氧缺陷位点, 可有效吸附并活化二氧化碳和氢气. 为深入了解反应机理并设计更高性能的潜在纳米催化剂, 需对氧化铟基纳米催化剂在二氧化碳加氢方面的研究进展进行总结. 本综述首先总结了不同晶型的氧化铟及其与金属氧化物或金属纳米粒子形成的复合催化剂用于催化二氧化碳选择性加氢制备C1产物的性能. 随后, 探讨了氧化铟与不同类型的沸石的复合物用于催化二氧化碳加氢制备C₂₊产物的性能. 最后, 提出了目前氧化铟基纳米催化剂在催化二氧化碳选择性加氢方面存在的挑战和未来的发展方向. 希望本文能够为设计具有高活性、 高选择性和高稳定性催化二氧化碳加氢的新型氧化铟基纳米催化剂提供一些思路.