Scalable synthesis of nanoporous boron for high efficiency ammonia electrosynthesis

Abstract: Three-dimensional bicontinuous nanoporosity fabricated by dealloying can provide unique chemical properties in catalytic materials, which conventional nanoparticulate catalysts do not have. Although many solid elements in the periodic table have been fabricated as nanoporous materials by dealloying, technically important nanoporous boron has not been realized because of the poor diffusivity and high chemical stability of boron. Here we report a scalable top–down method to produce three-dimensional nanoporous boron by selectively leaching a less stable metal compound phase from rapidly solidified two-phase metal–boron alloys. The metalloid boron phase with relatively high chemical stability remains as the skeleton of a nanoporous structure. The resultant nanoporous boron with tunable pore sizes, and porosities, shows superior catalytic activities towards ammonia electrosynthesis. This work provides a new approach to fabricate nanoporous metalloids for a wide range of functional applications and brings boron, an important functional material, to the family of dealloyed nanoporous materials.

https://doi.org/10.1016/j.mattod.2020.04.012