School of Materials Science and Engineering, Hebei University of Technology, 8 of First Road of Dingzigu, Hongqiao District, Tianjin 300130, China.
School of Chemistry and Chemical Engineering, University of Jinan, 336 West Nanxinzhuang Road, Jinan 250022, China.
Molecules. 2018 Dec 6;23(12):3227. doi: 10.3390/molecules23123227.
Electrocatalysts for the oxygen reduction (ORR) reaction play an important role in renewable energy technologies, including fuel cells and metal-air batteries. However, development of cost effective catalyst with high activity remains a great challenge. In this feature article, a hybrid material combining ZnO nanoparticles (NPs) with reduced graphene oxide (rGO) is applied as an efficient oxygen reduction electrocatalyst. It is fabricated through a facile one-step hydrothermal method, in which the formation of ZnO NPs and the reduction of graphene oxide are accomplished simultaneously. Transmission electron microscopy and scanning electron microscopy profiles reveal the uniform distribution of ZnO NPs on rGO sheets. Cyclic voltammograms, rotating disk electrode and rotating ring disk electrode measurements demonstrate that the hierarchical ZnO/rGO hybrid nanomaterial exhibits excellent electrocatalytic activity for ORR in alkaline medium, due to the high cathodic current density (9.21 × 10 mA/cm²), positive onset potential (-0.22 V), low H₂O₂ yield (less than 3%), and high electron transfer numbers (4e from O₂ to H₂O). The proposed catalyst is also compared with commercial Pt/C catalyst, comparable catalytic performance and better stability are obtained. It is expected that the ZnO/rGO hybrid could be used as promising non-precious metal cathode in alkaline fuel cells.
用于氧还原（ORR）反应的电催化剂在包括燃料电池和金属空气电池在内的可再生能源技术中起着重要作用。然而，开发具有高活性的成本效益高的催化剂仍然是一个巨大的挑战。在这篇专题文章中，将一种将氧化锌纳米粒子（NPs）与还原氧化石墨烯（rGO）结合的混合材料用作高效氧还原电催化剂。它是通过简便的一步水热法制备的，其中氧化锌 NPs 的形成和氧化石墨烯的还原同时进行。透射电子显微镜和扫描电子显微镜形貌揭示了 ZnO NPs 在 rGO 片上的均匀分布。循环伏安法、旋转圆盘电极和旋转环盘电极测量表明，分层 ZnO/rGO 杂化纳米材料在碱性介质中具有优异的 ORR 电催化活性，这归因于高阴极电流密度（9.21×10 mA/cm²）、正起始电位（-0.22 V）、低 H₂O₂产率（低于 3%）和高电子转移数（4e 从 O₂到 H₂O）。所提出的催化剂还与商业 Pt/C 催化剂进行了比较，得到了相当的催化性能和更好的稳定性。预计 ZnO/rGO 杂化材料可用于碱性燃料电池中作为有前途的非贵金属阴极。
