Anion‐Modulated HER and OER Activities of 3D Ni–V‐Based Interstitial Compound Heterojunctions for High‐Efficiency and Stable Overall Water Splitting. Issue 23 (16th April 2019)

• Record Type: Journal Article
• Authors: Yan, Haijing; Xie, Ying; Wu, Aiping; Cai, Zhicheng; Wang, Lei; Tian, Chungui; Zhang, Xiaomeng; Fu, Honggang
• Is Part Of: Advanced materials. Volume 31:Issue 23(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-04-16
• Subjects: heterojunctions -- metal interstitial compounds -- nitrides -- overall water splitting -- phosphides; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201901174
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Overall water splitting driven by a low voltage is crucial for practical H2 evolution, but it is challenging. Herein, anion‐modulation of 3D Ni–V‐based transition metal interstitial compound (TMIC) heterojunctions supported on nickel foam (Ni3 N‐VN/NF and Ni2 P‐VP2 /NF) as coupled hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalysts for efficient overall water splitting is demonstrated. The heterointerface in Ni3 N‐VN has a suitable H* absorption energy, being favorable for enhancing HER activity with onset overpotential (ηonset ) of zero and Tafel slope of 37 mV dec −1 in 1m KOH (close to that of Pt/C/NF). For the OER, the synergy of Ni2 P‐VP2 with oxide species can give enhanced activity with ηonset of 220 mV and Tafel slope of 49 mV dec −1 . The good activity is ascribed to heterointerface for activating the intermediates, good conductivity of TMICs for electron‐transfer, and porous structure facilitation of mass‐transport. Additionally, the minimal mutual influence of Ni3 N‐VN/NF and Ni2 P‐VP2 /NF allows easy coupling for efficient overall water splitting with a low driving voltage (≥1.43 V), a voltage of 1.51 V at 10 mA cm −2, and remarkable durability for 100 h. It can be driven by a solar cell (1.5 V), indicating its potential to store intermittent energy. Abstract : An anion‐modulation strategy is presented to create 3D Ni–V interstitial compound heterojunctions (Ni3 N–VN/nickel foam (NF) and Ni2 P‐VP2 /NF). The excellent hydrogen evolution reaction (HER) activity of Ni3 N–VN/NF and oxygen evolution reaction (OER) activity of Ni2 P–VP2 /NF and minimal mutual influence make them easy to couple to achieve overall water splitting with a low driving voltage and remarkable stability.