Surface engineering of nickel selenide for an enhanced intrinsic overall water splitting ability

• Published in: Materials chemistry frontiers 2018-09, Vol.2 (9), p.1725-1731
• Main Authors: Liu, Peng Fei, Zhang, Le, Zheng, Li Rong, Yang, Hua Gui
• Format: Article
• Language: English
• Subjects: Catalysis; Catalytic activity; Electrodes; Electrolysis; Energy technology; Hydrogen evolution reactions; Nickel; Oxygen evolution reactions; Performance enhancement; Polyanilines; Selenium; Water splitting
• ISSN: 2052-1537; 2052-1537
• DOI: 10.1039/C8QM00292D

The development of efficient catalytic electrodes towards the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is at the heart of renewable-energy technologies. Despite the tremendous efforts towards engineering electrode schemes for increasing exposed surface areas and active sites, improving intrinsic catalytic activity still remains a great challenge. Here, we develop a surface-polyaniline (PANI) functionalized nickel selenide (NiSe–PANI) electrode with great performance enhancement for both the HER and OER. The decorated PANI layer subtly modulates the surface electronic structures of NiSe, with a surface-optimized selenium-enriched configuration for the HER and enhanced generation of Ni III/IV active species when oxidized for the OER. When used as a bifunctional electrocatalyst for overall water splitting, the NiSe–PANI electrode displays excellent performance, with a current density of ∼10 mA cm −2 at an applied voltage of 1.53 V during a long-term electrolysis test, and outperforms the Pt and IrO 2 combination as the benchmark and most of the earth-abundant material-based bifunctional catalysts. Similar PANI–functionalization on other bifunctional nickel chalcogenide electrodes also exhibits obviously enhanced performance for overall water splitting, demonstrating the wider applicability of intrinsic activity enhancement via a surface electronic modulation strategy.