Metal–organic framework-derived integrated nanoarrays for overall water splitting

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 6; no. 19; pp. 9009 - 9018
• Main Authors: Guan, Cao, Wu, Haijun, Ren, Weina, Yang, Chunhai, Liu, Ximeng, Ouyang, Xiaofang, Song, Zeyi, Zhang, Yuzhong, Pennycook, Stephen J., Cheng, Chuanwei, Wang, John
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2018
• Subjects: Carbon nanotubes; Catalysis; Catalysts; Coating effects; Electrocatalysts; Electrodes; Energy conversion; Hydrogen evolution reactions; Kirkendall effect; Metals; Nanospheres; Noble metals; Oxygen evolution reactions; pH effects; Renewable energy; Sulfuric acid; Sustainability; Water splitting
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/C8TA02528B

Earth-abundant electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in a wide pH range are highly desirable for sustainable energy conversion technologies, but challenging to develop. Herein, we report hollow CoP nanosphere-embedded carbon nanotube/nitrogen-doped carbon (NC-CNT/CoP) nanoarrays, in which a nanoscale Kirkendall effect generates few-layer graphene-coated hollow CoP nanospheres with abundant active sites. The integrated NC-CNT/CoP electrode behaves as an efficient pH-universal HER catalyst and, through in situ transformation, the derived materials show excellent OER performance. The NC-CNT/CoP-based electrolyzers achieve a current density of 10 mA cm −2 at low voltages of 1.63, 1.69, and 1.66 V in KOH, PBS, and H 2 SO 4 , respectively, which are similar to the values obtained using noble metal catalysts. Importantly, the integrated electrode exhibits superior stability than that of the benchmark noble metals in a wide pH range. This work presents a promising method for achieving nonprecious catalysts for efficient energy conversion.