The development of catalysts for the oxygen reduction reaction is a coveted objective of relevance to energy research. This study describes a metal-free approach to catalyzing the reduction of O2 into H2O2, based on the use of redox-active carbenium species. The most active catalysts uncovered by these studies are the bifunctional dications 1,8-bis(xanthylium)-biphenylene ([3]2+) and 4,5-bis(xanthylium)-9,9-dimethylxanthene ([4]2+) which promote the reaction when in the presence of decamethylferrocene as a reductant and methanesulfonic acid as a proton source. Based on electrochemical studies carried out with [4]2+, we propose that catalysis involves the intermediacy of an organic peroxide that, upon protonation, converts back into the starting dications while also releasing H2O2. Kinetic studies point to the second protonation event as being rate-determining.

中文翻译：

---

双功能碳鎓二甲基作为氧还原的无金属催化剂

开发用于氧还原反应的催化剂是与能源研究相关的一个令人梦寐以求的目标。本研究描述了一种基于使用氧化还原活性碳鎓物种的无金属催化 O2 还原为 H2O2 的方法。这些研究发现的最活跃的催化剂是双功能二甲基化 1,8-双(xanthylium)-联苯 ([3]2+) 和 4,5-bis(xanthylium)-9,9-二甲基呫吨 ([4]2+ ) 在存在作为还原剂的十甲基二茂铁和作为质子源的甲磺酸时促进反应。基于使用 [4]2+ 进行的电化学研究，我们建议催化涉及有机过氧化物的中介，该有机过氧化物在质子化后转化回起始指示剂，同时还释放 H2O2。