Li Liang, Guo Ying, Wang Xinran, Liu Xiaowei, Lu Yongwei
Laboratory for Low Dimensional Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
Langmuir. 2021 May 18;37(19):5986-5992. doi: 10.1021/acs.langmuir.1c00524. Epub 2021 May 7.
To develop precious-metal-free bifunctional catalysts for overall water splitting, ultraeven Mo-doped CoP composites (Mo-CoP) have been fabricated by an in situ phosphorization protocol using CoMo-layered double hydroxide (CoMo-LDH) as the precursor. The ordered arrangement of cations in the CoMo-LDH could be easily phosphored and generate the ultraevenly dispersed Mo element within the CoP structure, resulting in the excellent bifunctional catalyst for overall water splitting. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalytic activities of the composites present an increase first and then a decreasing tendency with increased Mo doping content. Among all the Mo-doped CoP materials, the composite with a Mo/Co mole ratio of 1/2.3 presents the highest HER activity and stability in acidic conditions. At the current density of -10 mA·cm in 0.5 M HSO, the overpotential is only 116 mV. In addition, the composite also presents excellent HER and OER performance under alkaline conditions. The overpotential is 118 mV for HER and 317 mV for OER at 10 mA cm in 1 M KOH. It requires a cell voltage of 1.7 V to achieve a current density of 10 mA·cm and maintains a stable water-splitting current for at least 24 h, which is superior to most reported alkaline media. This simple and efficient synthetic approach could also be used for ultraeven doping between other transition metal ions.
为了开发用于全解水的无贵金属双功能催化剂，采用原位磷化法，以钴钼层状双氢氧化物（CoMo-LDH）为前驱体，制备了超均匀的钼掺杂磷化钴复合材料（Mo-CoP）。CoMo-LDH中阳离子的有序排列易于磷化，并在CoP结构中产生超均匀分散的钼元素，从而得到用于全解水的优异双功能催化剂。随着钼掺杂量的增加，复合材料的析氢反应（HER）和析氧反应（OER）催化活性呈现先增加后降低的趋势。在所有钼掺杂的CoP材料中，Mo/Co摩尔比为1/2.3的复合材料在酸性条件下具有最高的HER活性和稳定性。在0.5 M H₂SO₄中，电流密度为-10 mA·cm⁻²时，过电位仅为116 mV。此外，该复合材料在碱性条件下也表现出优异的HER和OER性能。在1 M KOH中，电流密度为10 mA cm⁻²时，HER的过电位为118 mV，OER的过电位为317 mV。实现10 mA·cm⁻²的电流密度需要1.7 V的电池电压，并能保持至少24 h的稳定析水电流，这优于大多数已报道的碱性介质。这种简单有效的合成方法也可用于其他过渡金属离子之间的超均匀掺杂。
