The morphology-dependent electrocatalytic activities of spinel-cobalt oxide nanomaterials for direct hydrazine fuel cell application

摘要

The design of novel, Earth-abundant and efficient electrocatalytic active materials is key for direct-electrochemical oxidation fuel cells (DEOFCs). Herein, we report different morphologically tuned spinel-cobalt oxide (Co3O4) nanomaterials such as pellet-, flower-, cube- and sheet-like morphologies as anode catalysts for an enhanced hydrazine oxidation reaction (HOR) for the first time. It is found that sheet-structured Co3O4 nanomaterial exhibits excellent electrocatalytic performance towards the HOR in comparison to pellet-, flower- and cube-like morphologies. The as-fabricated Co3O4-sheet electrode demonstrates a high mass activity of similar to 2.24 A g(-1) with a low onset potential of 1.09 V (vs. RHE). The attained high catalytic activity of the Co3O4-sheet electrode is ascribed to the high porosity, two-dimensional (2-D) layered sheet morphology, nanoscale dimensions, and the high BET surface area, providing large accessible active sites for hydrazine adsorption and fast reaction kinetics. The present systematic and thorough investigation provides detailed relationships between the micro-/nano-structures of the electrode materials and their electrocatalytic performances, which could serve as a simple approach for the development of facile and robust electrode candidates for the HOR in alkaline media.