Chen Luyao, Wang Haiyan, Tan Lei, Qiao Danni, Liu Xien, Wen Yonghong, Hou Wanguo, Zhan Tianrong
Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science (Ministry of Education), State Key Laboratory Base of Eco-chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
Key Laboratory of Colloid & Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100, China.
J Colloid Interface Sci. 2022 Jul 15;618:141-148. doi: 10.1016/j.jcis.2022.03.072. Epub 2022 Mar 18.
Exploring the transition-metal-based bifunctional electrocatalysts with high performance for efficient water-splitting and urea electrolysis is significant but challenging. This work presents the in situ preparation of holey NiFe-LDH nanosheets on Ni foam (H-NiFe-LDH/NF) via a one-step hydrothermal method in the presence of PEO-PPO-PEO as the soft template. The holey NiFe-LDH nanosheets provide a high electrochemical surface area, more edge catalytic sites, and abundant oxygen vacancies. Consequently, H-NiFe-LDH/NF exhibits excellent catalytic activity to oxygen evolution, urea oxidation, and hydrogen evolution reactions (OER, UOR, and HER) with good stability in alkaline electrolytes. This electrode requires an overpotential of 261 mV for the OER, a potential of 1.480 V for the UOR to achieve a current density of 100 mA cm in alkaline solutions. By employing the self-supported electrode as both the anode and cathode, this electrolysis cell (H-NiFe-LDH/NF||H-NiFe-LDH/NF) gains current densities of 10 and 100 mA cm at low cell voltages of 1.575 and 1.933 V in the 1.0 M KOH solution. After adding 0.33 M urea, the voltages to deliver 10 and 100 mA cm respectively decrease to 1.418 and 1.691 V. The H-NiFe-LDH/NF electrode also shows excellent stability for water-splitting and urea electrolysis. This work not only contributes to developing a low-cost, high-efficiency, bifunctional electrocatalyst but also provides a practically feasible approach for urea-rich wastewater electrolysis.
探索具有高效析氢和尿素电解性能的过渡金属基双功能电催化剂具有重要意义，但也具有挑战性。这项工作提出了一种在聚环氧乙烷-聚环氧丙烷-聚环氧乙烷（PEO-PPO-PEO）作为软模板存在的情况下，通过一步水热法在泡沫镍（NF）上原位制备多孔NiFe-LDH纳米片（H-NiFe-LDH/NF）的方法。多孔NiFe-LDH纳米片具有高电化学表面积、更多的边缘催化位点和丰富的氧空位。因此，H-NiFe-LDH/NF在碱性电解质中对析氧、尿素氧化和析氢反应（OER、UOR和HER）表现出优异的催化活性，并具有良好的稳定性。该电极在碱性溶液中进行OER时需要261 mV的过电势，在UOR时达到100 mA cm的电流密度需要1.480 V的电势。通过将自支撑电极用作阳极和阴极，该电解槽（H-NiFe-LDH/NF||H-NiFe-LDH/NF）在1.0 M KOH溶液中，在1.575和1.933 V的低电池电压下分别获得了10和100 mA cm的电流密度。添加0.33 M尿素后，分别提供10和100 mA cm电流密度的电压分别降至1.418和1.691 V。H-NiFe-LDH/NF电极在析氢和尿素电解方面也表现出优异的稳定性。这项工作不仅有助于开发低成本、高效率的双功能电催化剂，还为富尿素废水的电解提供了一种切实可行的方法。
