Oxygen Vacancy Enhanced Catalytic Oxidation of H2S Based on ZnO Incoperated N-doped Hollow Carbon Nanofibers for Cathodes Construction of High-performance Li-S Batteries

Abstract

As one of the most toxic pollutants, hydrogen sulfide (H2S) poses a hazard to human health and the environment. Selective oxidation of H2S to elemental sulfur (S) over carbon-based catalysts has emerged as an interesting solution, due to the advantages of low reaction temperature (20-30 oC), high desulfurization efficiency and accuracy. Interestingly, the produced carbon-sulfur composites could be directly used as the cathodes for high-performance lithium-sulfur batteries (LSBs). Herein, a carbon-based catalyst consisted of nitrogen doped hollow carbon nanofibers (NHCFs) loading oxygen-deficient ZnO (Od-ZnO/NHCFs) is fabricated to achieve this integrated application. The oxygen vacancy in Od-ZnO/NHCFs is able to enhance the chemisorption of H2S, then generates the ZnO/ZnS heterostructure; besides, it can enrich the O2•− radicals through electrostatic interaction to improve the catalytic oxidation of adsorbed H2S to elemental sulfur. Meanwhile, the hollow framework of NHCFs enables rapid gas diffusion and adequate storage space for solid sulfur, thus the in-situ construction of a high S-loading cathode (S@Od-ZnO/ZnS/NHCFs) used for LSBs is realized during the desulfurization process. More importantly, the formed ZnO/ZnS heterostructure can boost the electrochemical kinetic behaviors in the discharge/charge processes of LSBs. Coupled with the physical confinement of hollow structure on polysulfides, the as-prepared S@Od-ZnO/ZnS/NHCFs cathode exhibits outstanding electrochemical performance in LSBs. This work opens up a new avenue to the synergistic application of high performance LIBs electrodes with the controlling and converting of sulfur-containing pollutants.