Chen Mingxing, Lu Shenglin, Fu Xian-Zhu, Luo Jing-Li
College of Materials Science and Engineering Shenzhen University Shenzhen 518060 China.
Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic Engineering Shenzhen University Shenzhen 518060 China.
Adv Sci (Weinh). 2020 Mar 28;7(10):1903777. doi: 10.1002/advs.201903777. eCollection 2020 May.
Efficient electrocatalysts for the oxygen evolution reaction (OER) are highly desirable because of the intrinsically sluggish kinetics of OER. Herein, core-shell structured nanospheres of NiFe Sn@NiFe (oxy)hydroxide (denoted as NiFe Sn-A) are prepared as active OER catalysts by a facile electrochemical strategy, which includes electrodeposition of NiFe Sn alloy nanospheres on carbon cloth (CC) and following anodization. The alloy core of NiFe Sn could promote charge transfer, and the amorphous shell of NiFe (oxy)hydroxide is defect-rich and nanoporous due to the selective electrochemical etching of Sn in alkaline medium. The optimized catalyst of NiFeSn-A displays a remarkable OER performance with a low overpotential of 260 mV to reach the current density of 10 mA cm, a small Tafel slope of 50 mV dec, a high turnover frequency of 0.194 s at an overpotential of 300 mV, and a robust durability. Further characterizations indicate that the superior OER performance of the core-shell structured NiFeSn-A nanospheres might originate from abundant active sites and small charge transfer resistance. This work brings a new perspective to the design and synthesis of core-shell structured nanospheres for electrocatalysis through a facile electrochemical strategy.
由于析氧反应（OER）本身动力学缓慢，因此非常需要高效的OER电催化剂。在此，通过一种简便的电化学策略制备了核壳结构的NiFeSn@NiFe（氧）氢氧化物纳米球（表示为NiFeSn-A）作为活性OER催化剂，该策略包括在碳布（CC）上电沉积NiFeSn合金纳米球并随后进行阳极氧化。NiFeSn的合金核可促进电荷转移，并且由于在碱性介质中对Sn进行选择性电化学蚀刻，NiFe（氧）氢氧化物的非晶壳富含缺陷且具有纳米多孔结构。优化后的NiFeSn-A催化剂表现出卓越的OER性能，在达到10 mA cm的电流密度时过电位低至260 mV，塔菲尔斜率小至50 mV dec，在300 mV的过电位下周转频率高达0.194 s，并且具有出色的耐久性。进一步的表征表明，核壳结构的NiFeSn-A纳米球优异的OER性能可能源于丰富的活性位点和较小的电荷转移电阻。这项工作通过一种简便的电化学策略为电催化核壳结构纳米球的设计和合成带来了新的视角。
