Multilayered Molybdate Microflowers Fabricated by One‐Pot Reaction for Efficient Water Splitting

• Published in: Advanced science 2023-05, Vol.10 (14), p.e2206952-n/a
• Main Authors: Wang, Jingyi, Feng, Jianrui, Li, Yuying, Lai, Feili, Wang, Gui‐Chang, Liu, Tianxi, Huang, Jiajia, He, Guanjie
• Format: Article
• Language: English
• Subjects: bifunctional electrocatalyst; Corrosion resistance; doping; Electrolytes; lanthanum ammonium molybdate; lattice defects; microflowers; Morphology; Scanning electron microscopy; water splitting
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202206952

The development of high‐performance, low‐cost and rapid‐production bifunctional electrocatalysts towards overall water splitting still poses huge challenges. Herein, the authors utilize a facile hydrothermal method to synthesize a novel structure of Co‐doped ammonium lanthanum molybdate on Ni foams (Co‐ALMO@NF) as self‐supported electrocatalysts. Owing to large active surfaces, lattice defect and conductive channel for rapid charge transport, Co‐ALMO@NF exhibits good electrocatalytic performances which requires only 349/341 mV to achieve a high current density of 600 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Besides, a low cell voltage of 1.52 V is required to reach the current density of 10 mA cm−2 in alkaline medium along with an excellent long‐term stability for two‐electrode configurations. Density functional theory calculations are performed to reveal the reaction mechanism on Co‐ALMO@NF, which shows that the Mo site is the most favorable ones for HER, while the introduction of Co is beneficial to reduce the adsorption intensity on the surface of Co‐ALMO@NF, thus accelerating OER process. This work highlighted the importance of the structural design for self‐supporting electrocatalysts. Co‐doped ammonium lanthanum molybdate compounds are synthesized as bifunctional self‐supporting electrocatalysts by facile hydrothermal method. The lattice defects induced by metal doping excite more active sites and enhance electronic conductivity. Consequently, the cell voltage of the constructed two‐electrode system is only 1.52 and 1.64 V to drive the current densities of 10 and 100 mA cm−2.