Shimizu Kenichi, Sepunaru Lior, Compton Richard G
Physical and Theoretical Chemistry Laboratory , Department of Chemistry , The University of Oxford , South Parks Road , Oxford , OX1 3QZ , UK . Email:
Chem Sci. 2016 May 1;7(5):3364-3369. doi: 10.1039/c6sc00139d. Epub 2016 Feb 11.
A combination of chemical and electrochemical catalysis is introduced herein as a new approach to overcome one of the most challenging and persistent issues in fuel cell cathodes. Demonstrated using hematite (α-FeO) nanoparticles modified glassy carbon electrode, this bifunctional fuel cell catalyst system prevails the slow kinetics of the oxygen reduction reaction by rapid heterogeneous disproportionation of hydrogen peroxide. Whilst the catalytic efficiency of glassy carbon is limited to the two-electron reduction of oxygen, modification with hematite drastically improves it to equivalent to the four-electron pathway. This is due to regeneration of the cathodic fuel through the rapid decomposition of hydrogen peroxide. The importance of such system is stressed as the formation of water rather than hydrogen peroxide is essential to maximize the energy output of the fuel cell. Cycling of oxygen reduction/regeneration boosts the activity of a low-cost catalyst to be comparable to that of platinum and concurrently reduces the risk of cell degradation.
本文介绍了一种化学催化与电化学催化相结合的新方法，以克服燃料电池阴极中最具挑战性和持续性的问题之一。通过使用赤铁矿（α-Fe₂O₃）纳米颗粒修饰玻碳电极进行演示，这种双功能燃料电池催化剂体系通过过氧化氢的快速非均相歧化作用克服了氧还原反应缓慢的动力学问题。虽然玻碳的催化效率仅限于氧的两电子还原，但用赤铁矿修饰可将其显著提高至相当于四电子途径。这是由于通过过氧化氢的快速分解实现了阴极燃料的再生。强调了这种体系的重要性，因为形成水而非过氧化氢对于最大化燃料电池的能量输出至关重要。氧还原/再生循环提高了低成本催化剂的活性，使其与铂相当，同时降低了电池降解的风险。
