Yan Haijing, Xie Ying, Wu Aiping, Cai Zhicheng, Wang Lei, Tian Chungui, Zhang Xiaomeng, Fu Honggang
Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin, 150080, P. R. China.
Adv Mater. 2019 Jun;31(23):e1901174. doi: 10.1002/adma.201901174. Epub 2019 Apr 16.
Overall water splitting driven by a low voltage is crucial for practical H evolution, but it is challenging. Herein, anion-modulation of 3D Ni-V-based transition metal interstitial compound (TMIC) heterojunctions supported on nickel foam (Ni N-VN/NF and Ni P-VP /NF) as coupled hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalysts for efficient overall water splitting is demonstrated. The heterointerface in Ni N-VN has a suitable H* absorption energy, being favorable for enhancing HER activity with onset overpotential (η ) of zero and Tafel slope of 37 mV dec in 1 m KOH (close to that of Pt/C/NF). For the OER, the synergy of Ni P-VP with oxide species can give enhanced activity with η of 220 mV and Tafel slope of 49 mV dec . 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 Ni N-VN/NF and Ni P-VP /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 , and remarkable durability for 100 h. It can be driven by a solar cell (1.5 V), indicating its potential to store intermittent energy.
由低电压驱动的全水解对于实际的析氢反应至关重要，但具有挑战性。在此，展示了对负载在泡沫镍上的三维镍钒基过渡金属间隙化合物（TMIC）异质结（Ni N-VN/NF和Ni P-VP /NF）进行阴离子调制，作为耦合析氢反应（HER）和析氧反应（OER）的催化剂用于高效全水解。Ni N-VN中的异质界面具有合适的H*吸收能，有利于提高HER活性，在1 m KOH中起始过电位（η ）为零，塔菲尔斜率为37 mV dec⁻¹（接近Pt/C/NF）。对于OER，Ni P-VP与氧化物物种的协同作用可使活性增强，η为220 mV，塔菲尔斜率为49 mV dec⁻¹。良好的活性归因于用于活化中间体的异质界面、TMICs用于电子转移的良好导电性以及促进传质的多孔结构。此外，Ni N-VN/NF和Ni P-VP /NF之间的相互影响最小，便于以低驱动电压（≥1.43 V）、10 mA cm⁻²时1.51 V的电压进行高效全水解耦合，并具有100小时的显著耐久性。它可以由太阳能电池（1.5 V）驱动，表明其存储间歇性能量的潜力。
