Liu Guanyu, Hall Jeremy, Nasiri Noushin, Gengenbach Thomas, Spiccia Leone, Cheah Mun Hon, Tricoli Antonio
Nanotechnology Research Laboratory, Research School of Engineering, The Australian National University, Canberra, 2001, Australia.
Research School of Chemistry, The Australian National University, Canberra, 2001, Australia.
ChemSusChem. 2015 Dec 21;8(24):4162-71. doi: 10.1002/cssc.201500704. Epub 2015 Nov 30.
Chemical energy storage by water splitting is a promising solution for the utilization of renewable energy in numerous currently impracticable needs, such as transportation and high temperature processing. Here, the synthesis of efficient ultra-fine Mn3O4 water oxidation catalysts with tunable specific surface area is demonstrated by a scalable one-step flame-synthesis process. The water oxidation performance of these flame-made structures is compared with pure Mn2O3 and Mn5O8, obtained by post-calcination of as-prepared Mn3O4 (115 m(2) g(-1)), and commercial iso-structural polymorphs, probing the effect of the manganese oxidation state and synthetic route. The structural properties of the manganese oxide nanoparticles were investigated by XRD, FTIR, high-resolution TEM, and XPS. It is found that these flame-made nanostructures have substantially higher activity, reaching up to 350 % higher surface-specific turnover frequency (0.07 μmolO2 m(-2) s(-1)) than commercial nanocrystals (0.02 μmolO2 m(-2) s(-1)), and production of up to 0.33 mmolO2 molMn (-1) s(-1). Electrochemical characterization confirmed the high water oxidation activity of these catalysts with an initial current density of 10 mA cm(-2) achieved with overpotentials between 0.35 and 0.50 V in 1 m NaOH electrolyte.
通过水分解进行化学储能是一种很有前景的解决方案，可用于满足目前许多难以实现的需求中的可再生能源利用，例如交通运输和高温处理。在此，通过可扩展的一步火焰合成工艺展示了具有可调比表面积的高效超细Mn3O4水氧化催化剂的合成。将这些火焰制备结构的水氧化性能与通过对制备好的Mn3O4（115 m² g⁻¹）进行后煅烧得到的纯Mn2O3和Mn5O8以及商业同结构多晶型物进行比较，探究锰氧化态和合成路线的影响。通过XRD、FTIR、高分辨率TEM和XPS研究了氧化锰纳米颗粒的结构性质。结果发现，这些火焰制备的纳米结构具有显著更高的活性，其表面特异性周转频率（0.07 μmolO2 m⁻² s⁻¹）比商业纳米晶体（0.02 μmolO2 m⁻² s⁻¹）高出多达350%，并且产氧量高达0.33 mmolO2 molMn⁻¹ s⁻¹。电化学表征证实了这些催化剂具有高水氧化活性，在1 m NaOH电解液中，过电位在0.35至0.50 V之间时，初始电流密度可达10 mA cm⁻²。
