Industry-applicable, efficient hydrogen evolution reaction through an interface-activated bimetallic electrode with seawater photolysis in alkaline media

Abstract

<p><a><b>Hydrogen evolution reaction (HER) electrocatalysts over platinum (Pt) in an alkaline medium is crucial for hydrogen economy. Herein, we demonstrate new concept “interface-active electrode” to transform naturally inert alkaline HER materials towards industry-applicable HER electrocatalyst, comprised of interface-rich NiP<sub>2</sub>-FeP<sub>2</sub> on Cu nanowires that required overpotential as low as 23.6 and 357 mV at -10 and -1000 mA/cm<sup>2</sup>, respectively, with exceptional stability at the industrial current density of -1 A cm<sup>-2</sup>, superior to commercial Pt under alkaline solution. Structural characterization and theoretical calculations revealed the abundant interface between facets of NiP<sub>2</sub>-FeP<sub>2 </sub>on Cu exhibits optimum H adsorption-free energy than Pt and lower kinetic barrier for water dissociation (Δ<i>G</i><sub>B</sub> = 0.16 eV), boosting alkaline HER. Additionally, when integrated in a water splitting device, generated 10 mA/cm<sup>2 </sup>at only </b></a><b>1.42, 1.4, and 1.31 V </b><b>under 1 M KOH, artificial seawater at 25 ̊C and 100 ̊C, respectively, along with high solar-to-hydrogen (STH) conversion efficiency of 19.85</b><b> %. </b></p>

RuO2-NiO Nanosheets on Conductive Nickel Foam for Reliable and Regeneratable Seawater Splitting

“…Therefore, the large current density performance of our self-standing RuO 2 -NiO NSs/NF electrode was carried out and compared to the commercial Pt/C and Pt plate (Figure a). The commercial Pt/C and Pt plate show similar overpotentials to reach large current densities as the literature: e.g., for Pt/C 240 mV @ 500 mA cm –2 and 410 mV @ 1000 mA cm –2 and for the Pt plate 630 mV @ 500 mA cm –2 and 740 mV @ 1000 mA cm –2 . , Note that much smaller overpotentials are required for the RuO 2 -NiO NSs/NF electrode to reach the same current densities: 88 mV @ 500 mA cm –2 and 130 mV @ 1000 mA cm –2 , which are also superior to the reported catalysts for large current densities such as MoNi 4 /MoO 3– x (114 mV @ 500 mA cm –2 and 156 mV @ 1000 mA cm –2 ), NiP 2 -FeP 2 /CuNW/Cu f hybrid (323 mV @ 500 mA cm –2 and 357 mV @ 1000 mA cm –2 ), and α-MoB 2 (564 mV @ 1000 mA cm –2 ) …”

“…The commercial Pt/C and Pt plate show similar overpotentials to reach large current densities as the literature: e.g., for Pt/C 240 mV @ 500 mA cm −2 and 410 mV @ 1000 mA cm −2 and for the Pt plate 630 mV @ 500 mA cm −2 and 740 mV @ 1000 mA cm −2 . 57,58 Note that much smaller overpotentials are required for the RuO 2 -NiO NSs/NF electrode to reach the same current densities: 88 mV @ 500 mA cm −2 and 130 mV @ 1000 mA cm −2 , which are also superior to the reported catalysts for large current densities such as MoNi 4 /MoO 3−x (114 mV @ 500 mA cm −2 and 156 mV @ 1000 mA cm −2 ), 59 NiP 2 -FeP 2 /CuNW/Cu f hybrid (323 mV @ 500 mA cm −2 and 357 mV @ 1000 mA cm −2 ), 60 and α-MoB 2 (564 mV @ 1000 mA cm −2 ). 61 Besides the excellent electrochemical performance, our RuO 2 -NiO NSs/NF electrode also displays outstanding flexibility and cycling durability.…”