A Direct Formaldehyde Fuel Cell for CO2-Emission Free Co-generation of Electrical Energy and Valuable Chemical/Hydrogen

Converting carbon-based molecular fuels into electricity efficiently and cleanly without emitting CO₂ remains a challenge. Conventional fuel cells using noble metals as anode catalysts often suffer performance degradation due to CO poisoning and a host of problems associated with CO₂ production. This study provides a CO₂-emission-free direct formaldehyde fuel cell. It enables a flow of electricity while producing H₂ and valuable formate. Unlike conventional carbon-based molecules electrooxidation, formaldehyde 1-electron oxidation is performed on the Cu anode with high selectivity, thus generating formate and H₂ without undergoing CO₂ pathway. In addition, the fuel cell produces 0.62 Nm³ H₂ and 53 mol formate per 1 kWh of electricity generated, with an open circuit voltage of up to 1 V and a peak power density of 350 mW cm⁻². This study puts forward a zero-carbon solution for the efficient utilization of carbon-based molecule fuels that generates electricity, hydrogen and valuable chemicals in synchronization.     

关于弯曲界面气液两相相平衡化学势相等热力学判据的讨论

Thermodynamic criterion of equal chemical potential for phase equilibrium between gas and liquid in curved interface has been introduced in many textbooks and papers. In this paper, the process of the derivation of the criterion is proved to be wrong with analysis. In order to solve the problem, a proof procedure for the thermodynamic criterion of equal chemical potential is provided based on the definition of chemical potential. At the same time, a new thermodynamic criterion of two-phase equilibrium in curved interface is established using Gibbs interface thermodynamics and a new method for derivation of Kelvin equation is put forward based on the thermodynamic criterion of two-phase equilibrium. The new criterion which is derived directly from the second law of thermodynamics has a specific thermodynamic significance and clear physical model.     

工业尺寸固体氧化物燃料电池高效及阳极安全运行条件研究

固体氧化物燃料电池(Solid Oxide Fuel Cell, SOFC)是一种清洁高效的能源转化装置, 如何提高SOFC的发电效率, 并保证阳极不发生局部氧化, 是工业界与学术界的焦点问题之一. 建立了工业尺寸SOFC的效率测试与评价方法, 通过对比多组高燃料利用率下的电池效率测试结果, 发现在相同燃料利用率下, 电压会随电流的增大而下降. 因此, 较低的电流有利于达到更高的效率, 较大的电流则有利于输出更高的功率. 此外, 研究了高燃料利用率下放电时电压波动与阳极局部氧化的关联, 通过分析阳极Ni的临界氧化条件, 提出了避免发生阳极局部氧化的电池安全运行条件: 电池的输出电压应高于Ni的临界氧化电动势. 基于所采用的电池和测试参数, 发现在各个电流及温度下, SOFC发电效率大于50%时, 对应的燃料利用率一般在77%~90%这一区间内, 当燃料利用率为87.10%时, 电池具有最大的发电效率. 尽管对于不同材料、结构和制备工艺的SOFC, 其最高效率所对应的工况会有所差异, 但所提出的效率测试及评价方法和阳极安全运行的判断条件具有一定的普适性, 可以根据实际需求中高功率、高效率及长期稳定运行的重要程度, 确定相应的高效及阳极安全运行条件.