Bifunctional Porous NiFe/NiCo2O4/Ni Foam Electrodes with Triple Hierarchy and Double Synergies for Efficient Whole Cell Water Splitting
Bifunctional Porous NiFe/NiCo2O4/Ni Foam Electrodes with Triple Hierarchy and Double Synergies for Efficient Whole Cell Water Splitting
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DOI：
10.1002/adfm.201505302
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发表时间：
2016-05-24
影响因子：
19
通讯作者：
Zhao, Chuan
中科院分区：
文献类型：
--
作者：
Xiao, Changlong;Li, Yibing;Zhao, Chuan
以富土金属Ni、Fe和Co为基材，采用简单的水热和电沉积方法制备了三维分层多孔催化剂结构，并进行了高效的析氧反应（OER）和析氢反应（HER）。该电极由三层多孔结构组成，包括底部的超级大孔Ni泡沫（约500 μ m）衬底，中间层垂直排列的大孔NiCo2O4纳米片（约500 nm），以及顶部的NiFe（氧）氢氧化物介孔纳米片（约5 nm）。这种分层结构是无粘合剂的，有利于暴露催化活性位点，增强质量传输和加速电解过程中产生的气体的耗散。作为阳极催化剂，设计的分层电极具有优异的OER催化活性，过电位为340 mV，可实现1200 mA cm（-2）的高电流密度。作为阴极催化剂，该催化剂表现出优异的HER性能，其过电位为105 mV，电流密度为10 mA cm（-2）。作为双电极电解系统的阳极和阴极催化剂，设计的电极只需要1.67 V的电位就可以提供10 mA cm（-2）的电流密度，并且在长时间的大量碱性电解中表现出优异的耐久性。
A 3D hierarchical porous catalyst architecture based on earth abundant metals Ni, Fe, and Co has been fabricated through a facile hydrothermal and electrodeposition method for efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The electrode is comprised of three levels of porous structures including the bottom supermacroporous Ni foam (approximate to 500 mu m) substrate, the intermediate layer of vertically aligned macroporous NiCo2O4 nanoflakes (approximate to 500 nm), and the topmost NiFe(oxy)hydroxide mesoporous nanosheets (approximate to 5 nm). This hierarchical architecture is binder-free and beneficial for exposing catalytic active sites, enhancing mass transport and accelerating dissipation of gases generated during water electrolysis. Serving as an anode catalyst, the designed hierarchical electrode displays excellent OER catalytic activity with an overpotential of 340 mV to achieve a high current density of 1200 mA cm(-2). Serving as a cathode catalyst, the catalyst exhibits excellent performance toward HER with a moderate overpotential of 105 mV to deliver a current density of 10 mA cm(-2). Serving as both anode and cathode catalysts in a two-electrode water electrolysis system, the designed electrode only requires a potential of 1.67 V to deliver a current density of 10 mA cm(-2) and exhibits excellent durability in prolonged bulk alkaline water electrolysis.