Porous Pd/NiFeOx Nanosheets Enhance the pH‐Universal Overall Water Splitting

• Published in: Advanced functional materials Vol. 31; no. 51
• Main Authors: Zhang, Wen, Jiang, Xue, Dong, Zemeng, Wang, Jing, Zhang, Ning, Liu, Jie, Xu, Guang‐Rui, Wang, Lei
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.12.2021
• Subjects: 2D porous nanosheets, bifunctional electrocatalysts; Catalysts; Catalytic activity; Chemical composition; Corrosion resistance; Current density; Hydrogen evolution reactions; Materials science; Metal foams; Nanosheets; oxygen evolution reaction; Oxygen evolution reactions; Palladium; Sulfuric acid; Water splitting; wide pH range
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202107181

Modulating the morphology and chemical composition is an efficient strategy to enhance the catalytic activity for water splitting, since it is still a great challenge to develop a bifunctional catalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) over a wide pH range. Herein, Pd/NiFeOx nanosheets are synthesized with tightly arranged petal nanosheets and uniform mesoporous structure on nickel foam (NF). The porous 2D structure yields a larger surface area and exposes more active sites, facilitating water splitting at all pH values. The overpotential of Pd/NiFeOx nanosheets for OER is only 180, 169, and 310 mV in 1 m KOH, 0.5 m H2SO4, and 1 m phosphate‐buffered saline (PBS) conditions at 10 mA cm−2 current density, as well as excellent HER activity with ultralow overpotential in a wide pH range. When using porous Pd/NiFeOx nanosheets as bifunctional catalysts for water splitting, it just required a cell voltage of 1.57 V to reach a current density of 20 mA cm−2 with nearly 100% faradic efficiency in alkaline conditions, which is much lower than that of benchmark Pt/CǁRuO2 (1.76 V) couples, along with the improving stability benefiting from the good corrosion resistance of the inner NiFeOx nanosheets. The bifunctional electrocatalysts of Pd/NiFeOx with tightly arranged petal nanosheets and a uniform mesoporous structure on nickel foam are synthesized, which exhibit a superior activity and durability for overall water splitting in all pH values due to the larger surface area and exposes more active sites.