Direct borohydride-air fuel cells and batteries: toward non-precious metal catalysts and regenerative systems

可持续和负担得起的能源生产，为我们的现代社会正在采用的无数应用程序，范围从微到兆瓦的功率需求规模，需要各种系统具有特定的属性，为某一类应用程序。在燃料电池的背景下，直接硼氢化物（NaBH 4）燃料电池（DBFC）是较新的，在20世纪60年代首次提出，并在过去十年中才开始受到重视。DBFC可以克服更深入研究的燃料电池系统所面临的挑战（例如氢气、甲醇），原因有四个：a）它是在碱性介质中稳定的富氢液体燃料，因此它简化了燃料输送和储存，B）它具有较高的理论比能（9.3 Wh/g），与直接燃料电池中使用的液体燃料相比（甲醇、甲酸、乙醇），c）燃料中固有的碳的不存在消除了通常遇到的与CO2引起的催化剂中毒相关的问题，和d）DBFC提供了在阳极和阴极完全消除对昂贵的Pt基催化剂的需要的现实机会。Gyenge博士的小组是加拿大唯一一个研究DBFC的小组。这项研究结合了应用电催化和电化学工程的实验工作，以及与H。加塞，大坂大学，部门。应用物理学涉及三个关键领域：i）通过研究锇发现用于NaBH 4的完全8电子氧化的新型非贵金属催化剂（其本身比铂便宜五倍）作为模型，由于Gyenge博士的小组最近发现的锇的独特电催化活性和催化耐久性，ii）用于在碱性介质中还原氧的纳米结构MnO 2阴极的电沉积，iii）通过使用双功能电极研究NaBH 4的再生。

The sustainable and affordable generation of energy for the myriad of applications our modern society is employing, ranging in power requirement scale from micro-to mega-watts, demands a variety of systems with specific attributes for a certain class of applications. In the context of fuel cells, the direct borohydride (NaBH4) fuel cell (DBFC) is newer, having being first proposed in the 1960s and has started receiving significant attention only during the past decade. DBFC can overcome the challenges faced by much more intensely studied fuel cell systems (e.g. hydrogen, methanol) due to four factors: a) it is a hydrogen-rich liquid fuel stable in alkaline media, hence it simplifies the fuel delivery and storage, b) it has higher theoretical specific energy (9.3 Wh/g) compared to liquid fuels used in direct fuel cells (methanol, formic acid, ethanol), c) the inherent absence of carbon in the fuel removes the commonly encountered problems associated with catalyst poisoning by COad, and d) DBFC offers the realistic opportunity to eliminate completely the need for expensive Pt- based catalysts at both the anode and cathode. Dr. Gyenge's group is the only one in Canada studying DBFC. The research combines experimental work in applied electrocatalysis and electrochemical engineering with first-principles modelling of surface reactions which is carried out in collaboration with Prof. H. Kasai, Osaka University, Dept. of Applied Physics. Three critical areas are addressed: i) discovery of novel non-precious metal catalysts for the complete 8-electron oxidation of NaBH4 by studying osmium (which itself is five times cheaper than platinum) as a model, due to the unusal electrocatalytic activity and catalytic durability of osmium recently discovered by Dr. Gyenge's group, ii) electrodeposition of nanostructured MnO2 cathode for oxygen reduction in alkaline media, iii) investigation of the regeneration of NaBH4 by using bifunctional electrodes.