Highly efficient synthesis of extremely fine nano-SnO2 photocatalytic materials by dealloying Cu50Sn50 alloy powders with mainly exposed {123} facts in η-Cu6Sn5

Abstract

Extremely fine nano-SnO₂ photocatalysts were successfully synthesized by a dealloying method using high-corrosion-activity Cu₅₀Sn₅₀ alloy powders as precursor materials. The results showed that the dealloying cycles for Cu₅₀Sn₅₀ precursors prepared by ball milling at 300 and 150 r min⁻¹ could be significantly shortened to 2 and 2.5 h, respectively; among them, the Cu₅₀Sn₅₀ precursor prepared at 300 r min⁻¹ involved a shorter period of time because the precursor prepared at 300 r min⁻¹ exposed more unstable active crystal planes of {123} in η-Cu₆Sn₅ compared to the precursor prepared at 150 r min⁻¹. The results also showed that the nano-SnO₂ synthesized by dealloying Cu₅₀Sn₅₀ powders (which were prepared by ball milling at 300 and 150 r min⁻¹) consisted of large quantities of tiny particles with very small sizes of 2.5–4 and 2.5–5 nm, respectively. In addition, the results from the photodegradation experiments showed that the nano-SnO₂ synthesized by dealloying Cu₅₀Sn₅₀ alloy powders (which were prepared at 300 r min⁻¹) displayed the best photocatalytic performance, thus suggesting that Cu₅₀Sn₅₀ powders with mainly exposed active facets are perfect precursor materials for the highly efficient dealloying synthesis of extremely fine nano-SnO₂ with superior catalytic activity. This is the first time the influence of active crystal planes in the phase of precursors on the dealloying process has been investigated, which sets a good example for designing more ideal alloy systems with mainly exposed active crystal planes as precursors for the fast dealloying preparation of other novel photocatalysts.