Low-Pt supported on MOF-derived Ni(OH)2 with highly-efficiently electrocatalytic seawater splitting at high current density

Abstract

Developing highly effective and stable electrocatalysts are attractive but highly challenging for alkaline seawater splitting. Herein, using a simple method, we developed a novel MOF derived nanosheets-nanoparticle-structured Pt2/Ni(OH)2/NF catalyst. Benefiting from strong metal-support interaction (SMSI) of Pt-O-Ni bond at interface, the synergistic effect of Pt-O vacancies (Ov) sites and excellent superhydrophilic surface, catalyst delivered excellent catalytic activity in seawater splitting. The overpotential was 19 mV at 10 mA·cm−2, which surpassed the commercial 20% Pt/C. A photovoltaic cell yielded up to 13.5% STH conversion efficiency. Furthermore, the cell voltage at 10 mA·cm−2 for anion exchange membrane (AEM) seawater electrolyzer in our design with the Pt2/Ni(OH)2/NF cathode catalyst was merely 1.46 V. The energy consumption to produce 1 m3 of H2 at the current density of 200 mA·cm−2 was 3.8 kW·h, below that of NF= |NF (4.3 kW·h). Theoretical results showed that the localized charge density and electronic structure of Ni(OH)2 can be significantly modulated upon SMSI at interface and Ov. And the synergistic effect of Pt-Ov sites can balance the adsorption and desorption of H* . Ov could achieve high-efficiency adsorption of H2O and optimize hydrogen spillover from Ni(OH)2 to Pt, leading to excellent HER activity. This study provided a light in rational construction of robust seawater-based electrocatalysts for seawater splitting.