Yan Wenxiu, An Chao, Shen Yongli, Zeng Shuyuan, An Changhua
Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, School of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Advanced Functional Porous Materials, Institute for New Energy Materials & Low-Carbon Technologies, Tianjin University of Technology, Tianjin 300384, China.
School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong 252059, China.
Nanoscale. 2022 Sep 2;14(34):12275-12280. doi: 10.1039/d2nr01525k.
Engineering of the crystal structures of metallic nanomaterials is an alternative avenue to control the size and shape of nanocatalysts. However, the phase-controlled synthesis of Ni nanocatalysts is challenging because of its low reduction potential under mild conditions. We developed a room-temperature CH plasma conversion of Ni(OH) nanosheets to hexagonal close packed (hcp) Ni while maintaining a pristine shape. Increasing the temperature resulted in the formation of face-centered cubic (fcc) Ni. The hcp Ni nanosheets exhibited an overpotential of 85 mV at 10 mA cm for an electrocatalytic hydrogen evolution reaction (HER) in alkaline solution, which was superior to that of the fcc (122 mV) counterpart. Density-functional-theory calculations demonstrated that during the HER, the d-band center of hcp Ni was closer to the Fermi level, which aided the formation of H molecules. This work could facilitate the synthesis of other metastable metals and metallic alloys with high efficiency for various applications.
金属纳米材料晶体结构的工程设计是控制纳米催化剂尺寸和形状的另一条途径。然而，由于镍纳米催化剂在温和条件下还原电位较低，其相控合成具有挑战性。我们开发了一种室温下将氢氧化镍纳米片通过CH等离子体转化为六方密堆积（hcp）镍的方法，同时保持原始形状。温度升高导致面心立方（fcc）镍的形成。在碱性溶液中，hcp镍纳米片在10 mA cm下进行电催化析氢反应（HER）时的过电位为85 mV，优于fcc镍纳米片（122 mV）。密度泛函理论计算表明，在HER过程中，hcp镍的d带中心更接近费米能级，这有助于氢分子的形成。这项工作有助于高效合成其他亚稳金属和金属合金，以用于各种应用。
