Defect-rich CoMoS nanosheets on PANI nanowires as excellent hybrid electrocatalyst for water splitting

• Published in: Electrochimica acta Vol. 403; p. 139586
• Main Authors: Mathew, Sobin, Sim, Jun-Hyung, Rajmohan, Rajendiran, Li, Oi Lun, Cho, Young-Rae
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 20-01-2022; Elsevier BV
• Subjects: Current density; Defect rich structure; Electrocatalysts; Electron transfer; Hybrid catalysts; Hybrid structures; Hydrogen evolution reaction; Hydrogen evolution reactions; Metal foams; Nanosheets; Nanowires; Oxygen evolution reaction; Polyaniline; Polyanilines; Synergistic effect; Water splitting; Hydrogen evolution reaction; Water splitting; Oxygen evolution reaction; Defect rich structure; Polyaniline; Hybrid catalysts
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2021.139586

•Vertically aligned CoMoS nanosheet on a PANI coated nickel foam current collector.•CoMoS-PANI improve the intrinsic activity due to defect rich interstitial sites.•Assembled cell demonstrate ultrastability for 50 h at a current density 20 mA/cm2.•Designed electrocatalysts exhibit ultralow overpotential for HER and OER at 10 mA/cm2.•Cell achieved a low potential of 1.58 V at 10 mA/cm2 for water splitting.
Developing economic, efficient, and stable bifunctional electrocatalysts for producing oxygen and hydrogen simultaneously remains challenging. Here, we design and fabricate vertically aligned cobalt molybdenum sulfide (CoMoS) nanosheets on a conductive polyaniline (PANI) nanowire on nickel foam (NF) by a one-step solvothermal synthesis. The hybrid CoMoS-PANI array demonstrates low overpotentials of 250 and 98 mV, to achieve a current density of 10 mA cm–2 in an alkaline solution, for the oxygen and hydrogen evolution reactions, respectively. As an electrolyzer for overall water splitting, CoMoS-PANI/NF, as both the anode and the cathode, exhibits a current density of 10 mA cm–2 at a low cell voltage, 1.58 V. Furthermore, good stability for 50 h at a current density of 20 mA cm–2 during overall splitting suggests that CoMoS-PANI can be promoted as a highly efficient and stable bifunctional catalyst. The upgraded electrocatalytic activity of CoMoS-PANI can be ascribed to its defect-rich structure, the exhibition of the PANI nanowire to effective electron transfer, and the ample of active catalytic sites provided by the synergistic effect of the hybrid structures. This work is a promising step towards the design and exploration of hybrid materials as excellent electrocatalysts for renewable energy generation.
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