Key Laboratory of Macromolecular Science of Shaanxi Province, Shaanxi Key Laboratory for Advanced Energy Devices, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an 710062, China.
Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong.
J Colloid Interface Sci. 2018 Nov 1;529:325-331. doi: 10.1016/j.jcis.2018.06.014. Epub 2018 Jun 7.
Highly efficient proton exchange membrane electrolyzer in acidic media is of great importance for the hydrogen production from the electrochemical water splitting. Unfortunately, the electrochemical water splitting is limited by the slow oxygen evolution reaction kinetics at anode. So far, the synthesis of active and stable electrocatalysts in acid media is still a challenging work. In the work, carbon nanobowls supported ultrafine iridium nanocrystals are synthesized by a simple complexation-reduction method with assistance of 1-hydroxyethane-1, 1-diphosphonic acid, which effectively serves as as complexant, capping agent and surfactant during the synthesis. The good dispersion and ultrafine size of Ir nanocrystals, the modified interfacial property from phosphonate with excellent hydrophilicity, as well as carbon nanobowls as advanced carbon supports contribute to their excellent electrocatalytic activity for the oxygen evolution reaction in acid media. The as-prepared carbon nanobowls supported ultrafine iridium nanocrystals present an ultra-low overpotential of 290 mV to achieve the mass activity of 1000 A g and a small Tafel slope of 49.1 mV dec, which significantly outperform commercial Ir/C electrocatalyst. The remarkable activity and durability make carbon nanobowls supported ultrafine iridium nanocrystals as a potential candidate for the oxygen evolution reaction electrocatalyst in proton exchange membrane water electrolyzer.
在酸性介质中高效的质子交换膜电解槽对于通过电化学水分解生产氢气非常重要。不幸的是，电化学水分解受到阳极缓慢的析氧反应动力学的限制。迄今为止，在酸性介质中合成活性和稳定的电催化剂仍然是一项具有挑战性的工作。在这项工作中，通过简单的配合还原法，在 1-羟基乙烷-1,1-二膦酸的辅助下合成了负载在碳纳米碗中的超细铱纳米晶，在合成过程中，1-羟基乙烷-1,1-二膦酸有效地作为络合剂、封端剂和表面活性剂。Ir 纳米晶的良好分散性和超细尺寸、来自具有优异亲水性的膦酸盐的改性界面性质以及作为先进碳载体的碳纳米碗有助于它们在酸性介质中对析氧反应具有优异的电催化活性。所制备的负载在碳纳米碗中的超细铱纳米晶表现出超低的过电位 290 mV，实现了 1000 A g的质量活性和 49.1 mV dec 的小塔菲尔斜率，明显优于商业 Ir/C 电催化剂。其显著的活性和耐久性使负载在碳纳米碗中的超细铱纳米晶成为质子交换膜水电解中析氧反应电催化剂的潜在候选材料。
