A simple approach to strontium sodium tantalite mesocrystals with ultra-high photocatalytic properties for water splitting

Abstract

A novel kind of strontium sodium tantalite (SNT) mesocrystal has been synthesized via a simple molten salt process without using any organic additives. The SNT mesocrystals are characterized as built from nanocubes (20–60 nm) via a non-classical crystallization process. The obtained 3D architectures show high crystallinity and a preferred orientation growth. Formation of SNT mesocrystals strongly depends on the weight ratio (W) of salt to starting materials. An inappropriate value of W will restrain the orientation attachment and promote the process of classic crystallization. The SNT mesocrystals exhibit an outstanding photocatalytic performance due to their nanosteps, high porosity and preferred oriented direction. Rates of hydrogen generation reach values of 27.5 and 4.89 mmol h⁻¹ for aqueous methanol and pure water splitting, respectively. Besides, the molten salt method is suggested to be beneficial for large scale applications of catalysts due to its nontoxicity, recyclability, cheapness and high efficiency.