Partially hydroxylated ultrathin iridium nanosheets as efficient electrocatalysts for water splitting |
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| Authors: | Zifang Cheng Bolong Huang Yecan Pi Leigang Li Qi Shao Xiaoqing Huang |
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| Institution: | College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China;Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hong Kong, China |
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| Abstract: | Ultrathin two-dimensional (2D) materials have attracted considerable attention for their unique physicochemical properties and promising applications; however, preparation of freestanding ultrathin 2D noble metal remains a significant challenge. Here, for the first time, we report use of a wet-chemical method to synthesize partially hydroxylated ultrathin Ir nanosheets (Ir-NSs) of only five to six atomic layers’ thickness. Detailed analysis indicates that the growth confinement effect of carbon monoxide and the partially hydroxylated surface play a critical role in formation of the ultrathin structure. The ultrathin Ir-NSs exhibit excellent performance for both the hydrogen evolution reaction and oxygen evolution reaction in a wide pH range, outperforming the state-of-the-art Pt/C and IrO2, respectively. Density-functional theory calculations reveal that the partial hydroxylation not only enhances the surface electron transfer between Ir-sites and intermediate O-species, but also guarantees efficient initial activation of bond cleavage of H-O-H for first-step H2O splitting. This, ultimately, breaks through barriers to full water splitting, with efficient electron transfer essentially maintained. |
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| Keywords: | iridium nanosheet 2D material hydroxylation overall water splitting |
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