Zhang Longsheng, Bai Jing, Zhang Shouhan, Liu Yunxia, Ye Jinyu, Fan Wei, Debroye Elke, Liu Tianxi
Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China.
School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
ACS Nano. 2024 Aug 20;18(33):22095-22103. doi: 10.1021/acsnano.4c05377. Epub 2024 Aug 8.
Designing a high-performing iridium (Ir) single-atom catalyst is desired for acidic water electrolysis, which shows enormous potential given its high catalytic activity toward acidic oxygen evolution reaction (OER) with minimum usage of precious Ir metal. However, it still remains a substantial challenge to stabilize the Ir single atoms during the OER operation without sacrificing the activity. Here, we report a high-performing OER catalyst by immobilizing Ir single atoms on a polyimide support, which exhibits a high mass activity on a carbon paper electrode while simultaneously achieving outstanding stability with negligible decay for 360 h. The resulting electrode (denoted as Ir-PI@CP) reaches a 49.7-fold improvement in mass activity compared to the counterpart electrode prepared without polyimide support. Both our experimental and theoretical results suggest that, owing to the strong metal-support interactions, the polyimide support can enhance the Ir 5d states of Ir single atoms in Ir-PI@CP, which can tailor the adsorption energies of intermediates and decrease the thermodynamic barrier at the rate-determining step of the OER, but also facilitate the proton-electron-transfer process and improve the reaction kinetics. This work offers an alternative avenue for developing single-atom catalysts with superior activity and durability toward various catalytic systems and beyond.
设计一种高性能的铱（Ir）单原子催化剂用于酸性水电解是很有必要的，鉴于其对酸性析氧反应（OER）具有高催化活性且贵金属Ir的用量最少，因而展现出巨大的潜力。然而，在OER操作过程中稳定Ir单原子同时又不牺牲活性，仍然是一个重大挑战。在此，我们报道了一种通过将Ir单原子固定在聚酰亚胺载体上制备的高性能OER催化剂，该催化剂在碳纸电极上表现出高的质量活性，同时实现了出色的稳定性，在360小时内衰减可忽略不计。所得电极（记为Ir-PI@CP）与未使用聚酰亚胺载体制备的对照电极相比，质量活性提高了49.7倍。我们的实验和理论结果均表明，由于强的金属-载体相互作用，聚酰亚胺载体可以增强Ir-PI@CP中Ir单原子的Ir 5d态，这不仅可以调整中间体的吸附能并降低OER速率决定步骤的热力学势垒，还能促进质子-电子转移过程并改善反应动力学。这项工作为开发对各种催化体系及其他体系具有优异活性和耐久性的单原子催化剂提供了一条替代途径。
