Recently, the research team of Assistant Professor Fang Ming and Associate Professor Liu Wenjun from College of Materials Science and Engineering has made important progress in energy catalysis. The results have been published on the top journal "Advanced Energy Materials" (JCR Q1, impact factor:21.875). Assistant Professor Fang Ming of College of Materials Science and Engineering is the first author of the paper. Associate Professor Liu Wenjun and Professor Johnny C. Ho from City University of Hong Kong are the co-corresponding authors of the paper.
Earth-abundant amorphous nanomaterials with rich structural defects are promising alternative catalysts to noble metals for an efficient electrochemical oxygen evolution reaction; however, their inferior electrical conductivity and poor morphological control during synthesis hamper the full realization of their potency in electrocatalysis. Herein, a rapid surface-guided synthetic approach is proposed to introduce amorphous and mixed-metal oxyhydroxide overlayers on ultrathin Ni-doped MnO2 (Ni-MnO2) nanosheet arrays via a galvanic replacement mechanism.
This method results in a monolithic 3D porous catalyst with a small overpotential of only 232 mV to achieve a current density of 10 mA cm(-2) in 1 m KOH, which is much lower than the corresponding value of 307 mV for the Ni-MnO2 reference sample. Detailed structural and electrochemical characterization reveal that the unique Ni-MnO2 ultrathin nanosheet arrays do not only provide a large surface area to guide the formation of active amorphous catalyst layers but also ensure the effective charge transport owing to their high electron conductivity, collectively contributing to the greatly improved catalyst activity. It is envisioned that this highly operable surface-guide synthetic strategy may open up new avenues for the design and fabrication of novel 3D nanoarchitectures integrated with functional amorphous materials for broadened ranges of applications.
Surface-Guided Formation of Amorphous Mixed-Metal Oxyhydroxides on Ultrathin MnO2 Nanosheet Arrays for Efficient Electrocatalytic Oxygen Evolution. DOI: 10.1002/aenm.202001059