Dhanaji B. Malavekar, Shivam Kansara, Mayur A. Gaikwad, Komal D. Patil, Suyoung Jang, Sang Woo Park, Hyojung Bae, Jang-Yeon Hwang, Jin Hyeok Kim
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引用次数: 0
Abstract
Nickel-based materials exhibit excellent electrochemical water splitting activity; however, their inferior mass transport limits further improvement in catalytic performance. Herein, we report a composite core–shell material consisting of spherical nanoparticles of NiWO4 and rGO sheets coated on crystalline NiO for overall water splitting in an alkaline medium. The macropores created from a uniform coating of spherical nanoparticles with rGO sheets impart high porosity and short diffusion passages, facilitating fast electrolyte flow and thereby enhancing mass transport capability. Benefiting from the excellent mass transport due to mesoporosity, NiO/NiWO4-rGO required an overpotential of 270 mV to achieve a current density of 50 mA cm−2 for OER and 54 mV to achieve a current density of -10 mA cm−2 for HER. A Tafel slope of 82 and 58 mV dec−1 for OER and HER was observed for NiO/NiWO4-rGO, respectively. Overall water splitting devices fabricated using NiO/NiWO4-rGO as an anode and cathode require a cell voltage of 1.59 V to enable a current density of 50 mA cm−2 with stability for over 50 h indicating a favorable morphological modulation at the interface of NiWO4-rGO shell structure coated on a crystalline NiO core, which lowers the overpotential requirement. The assembled water-splitting device performs water splitting 10 M KOH and requires only 1.55 V to reach the current density of 50 mA cm−2. Our density functional theory (DFT) calculations reveal the free energy profiles of hydrogen adsorption, guiding the experimental optimization of catalysts for efficient HER and OER. Furthermore, a seawater electrocatalysis device assembled using NiO/NiWO4-rGO required only 1.77 V to reach 50 mA cm−2 current density with stability over 50 h. This confirms that NiO/NiWO4-rGO is a potential material for industrial and practical water splitting.
期刊介绍:
Advanced Composites and Hybrid Materials is a leading international journal that promotes interdisciplinary collaboration among materials scientists, engineers, chemists, biologists, and physicists working on composites, including nanocomposites. Our aim is to facilitate rapid scientific communication in this field.
The journal publishes high-quality research on various aspects of composite materials, including materials design, surface and interface science/engineering, manufacturing, structure control, property design, device fabrication, and other applications. We also welcome simulation and modeling studies that are relevant to composites. Additionally, papers focusing on the relationship between fillers and the matrix are of particular interest.
Our scope includes polymer, metal, and ceramic matrices, with a special emphasis on reviews and meta-analyses related to materials selection. We cover a wide range of topics, including transport properties, strategies for controlling interfaces and composition distribution, bottom-up assembly of nanocomposites, highly porous and high-density composites, electronic structure design, materials synergisms, and thermoelectric materials.
Advanced Composites and Hybrid Materials follows a rigorous single-blind peer-review process to ensure the quality and integrity of the published work.