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Mixed Metal Phosphide Chainmail Catalysts Confined in N-Doped Porous Carbon Nanoboxes as Highly Efficient Water-Oxidation Electrocatalysts with Ultralow Overpotentials and Tafel Slopes.
ACS Applied Materials & Interfaces ( IF 9.5 ) Pub Date : 2020-01-17 , DOI: 10.1021/acsami.9b19504
Xin Zhang,Lei Zhang,Guo-Gang Zhu,Yuan-Xin Zhu,Shih-Yuan Lu

Electrocatalytic hydrogen production driven by surplus electric energies is considered a promising sustainable process for hydrogen supply. The high overpotential and low energy-conversion efficiency caused by the slow kinetics of the four-electron transfer oxygen-evolution reaction (OER), however, hamper its competitiveness. Herein, a highly stable, efficient OER catalyst was developed, taking the effects of both composition and nanostructure into account for the catalyst design. N-doped carbon-armored mixed metal phosphide nanoparticles confined in N-doped porous carbon nanoboxes, a particle-in-box nanostructure, were synthesized from monodisperse Ni3[Fe(CN)6]2·H2O nanocubes through sequential conformal polydopamine coating, ammonia etching, and thermal phosphorization. The product exhibited outstanding catalytic abilities for the OER in 1.0 M KOH, delivering 10, 100, and 250 mA/cm2 at ultrasmall overpotentials of 203, 242, and 254 mV, respectively, with an ultrasmall Tafel slope of 38 mV/dec, outperforming most recently reported top-notch iron-group-based OER catalysts. The long-term stability was also excellent, showing a small chronopotentiometric decay of 2.5% over a 24 h operation at 50 mA/cm2. The enhanced catalytic efficiency and stability may be attributable to the unique particle-in-box structure as a nanoreactor offering a local, fast reaction environment, the conductive N-doped porous carbon shell for fast charge and mass transport, the synergistic effect between multicomponent metal phosphides for enhanced intrinsic activities, and the carbon protection layer to prevent/delay the catalyst core from being deactivated. This combined particle-in-box and chainmail design concept for electrocatalysts is unique and advantageous and may be readily applied to the general field of heterogeneous reactions.

中文翻译:

限制在N掺杂多孔碳纳米盒中的混合金属磷化物链锁催化剂,是具有超低超电势和Tafel斜率的高效水氧化电催化剂。

由剩余电能驱动的电催化制氢被认为是有前途的可持续氢供应过程。但是,由于四电子转移氧演化反应(OER)动力学缓慢而导致的过高电势和低能量转换效率阻碍了它的竞争力。在此,开发了高度稳定,高效的OER催化剂,并考虑了催化剂设计的组成和纳米结构的影响。由单分散的Ni3 [Fe(CN)6] 2·H2O纳米立方体通过连续保形聚多巴胺涂层,氨水合成了N-掺杂的碳铠装混合金属磷化物纳米粒子蚀刻和热磷化。该产品对1.的OER表现出出色的催化能力。0 M KOH,分别以203、242和254 mV的超小超电势提供10、100和250 mA / cm2的电流,以38 mV / dec的超小Tafel斜率,胜过最新报道的顶尖铁基-基OER催化剂。长期稳定性也非常好,在50 mA / cm2的24小时工作时间内,计时电位的小衰减为2.5%。增强的催化效率和稳定性可归因于独特的盒内颗粒结构,因为它是提供局部快速反应环境的纳米反应器,导电的N掺杂多孔碳壳,可实现快速电荷和质量传输,多组分金属之间的协同效应磷化物可增强内在活性,碳保护层可防止/延迟催化剂核的失活。
更新日期:2020-01-21
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