Metal-Organic Framework-Derived Hollow Nanocubes as Stable Noble Metal-Free Electrocatalyst for Water Splitting at High Current Density

Alkaline water electrolysis is an environmentally friendly and promising approach to produce hydrogen. However, high cost, low efficiency, and poor stability are roadblocks to commercialization of electrocatalysts. This work aims to design and develop a highly efficient, durable, and cost-effective electrocatalyst toward water splitting through modifying metal-organic frameworks. The electrocatalytic performance and stability surpass those of noble metal benchmarks at high current density (1-10 A center dot cm(-2)). Theoretical calculations and in situ Raman spectra reveal the electronic structure of the synthesized catalyst and the mechanism of the catalytic reaction process, which rationalizes that the high catalytic activity and stability at high current are attributed to the unique electronic structure of cobalt regulated by copper and the protection provided by carbon nanotubes formed in situ, respectively. In addition, this paper proposes that the desorption ability of the catalyst toward the products (H-2 and O-2), rather than the adsorption ability toward the reactants (H+ or OH-), is more important to the sustainable and stable electrochemical water splitting progress at high current density, which is a kinetic rather than thermodynamic dominating process. The findings provide alternative insights to design and employ high performance catalysts to fuel hydrogen production as a clean energy source to tackle the global energy crisis. [GRAPHICS] .