N, S-codoped CNTs supported Co4S3 nanoparticles prepared by using CdS nanorods as sulfur sources and hard templates:
Dengke Zhao1, Zhenghua Tang2, Wei Xu2
1Guangzhou Key Laboratory for Surface Chemistry of Energy Materials, New Energy Research Institute, School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Petrochemical Pollution Process and Control, Guangdong University of Petrochemical Technology, Maoming 525000, China.
Abstract:
Non-precious efficient bifunctional catalysts towards oxygen reduction/evolution reactions (ORR/OER) are highly desired to enable the widespread application of rechargeable Zn-air batteries (r-ZABs). Herein, Prussian blue analogues (PBA) anchored on CdS nanorods (CdS NRs) pre-coated with polydopamine (PDA) are utilized as precursors to prepare ultrafine Co4S3 nanoparticles supported on N, S-codoped CNTs (Co4S3@N,S-CNT), where CdS NRs are served as sulfur sources and hard templates. After pyrolysis, the resulting Co4S3@N,S-CNT-800 shows a high specific surface area of 142.4 m2 g-1, together with merely 0.780 V difference between the OER potential at 10 mA cm-2 and the ORR potential at 3 mA cm-2. The Co4S3@N,S-CNT-800 based air cathode displays a higher discharge capacity of 787 mAh gZn-1 at 10 mA cm-2, a higher output power density of 154 mW cm-2, better working stability, as well as a lower charge-discharge voltage gap than the Pt/C + RuO2 based air electrode at various working current density. The remarkable oxygen reversible catalytic activities are mainly attributed to the presence of a thin layer of mesoporous carbon on partial sections of the open-end N,S-CNTs, which not only shortens the mass diffusion length but also prevents N,S-CNTs from excessively bundling to maximize the exposure of Co4S3 nanocrystallites and graphitized carbon skeletons with N or S heteroatoms.
