A nanotubular framework with customized conductivity and porosity for efficient oxidation and reduction of water

Abstract

To reduce the total cost of production of hydrogen and oxygen from water splitting, many efforts have been made to develop first row transition metal materials instead of precious platinum-group catalysts. Recently, porous catalysts with high conductivity for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) have attracted more attention. Here, a quaternary inorganic framework consisting of Ni⁰ and Ni(OH)₂, graphite-like C, and titanate nanotubes (referred to as the Ni^x/C/TNT framework) has been successfully fabricated. Compared to the precious Pt/C for the HER and IrO₂/C for the OER, the fabricated Ni^x/C/TNT framework exhibited high activities towards water splitting. At a current density of 10 mA cm⁻², its OER overpotential is as small as 280 mV while its HER overpotential is as small as 145 mV. The excellent electrochemical performance can be attributed to its unique structure of the Ni^x/C/TNT framework that can effectively expand the interface, maximize the reacting sites, and thus guarantee rapid mass and electron transfer.