Water-soluble
nonrare metal Ag–Sn–S nanocrystals
(ATS NCs) were green synthesized at room temperature using the interfacial
nucleation mechanism. Interfacial acids regulate the concentration
of hydroxide ions outside the complex, the sulfur sources attack the
cations at the complex interface, and the sulfur sources form covalent
bonds to complete crystal nucleation and growth at room temperature.
The band gap of ATS NCs synthesized by the interface nucleation mechanism
is 2.32∼2.59 eV, which gives it a higher redox ability and
very high photocatalytic degradation rate. A total of 0.8 mg of Ag2SnS3 NCs can achieve photocatalytic degradation
of more than 99% of MO (1 mg) under visible light (λ > 420
nm)
in 2 min with a photocatalytic rate constant of 2.1247 min–1. Interfacial regulation of acid protonation on the surface of ATS
NCs produced more defect states, which was conducive to trapping holes
(h+), promoting their transfer to organic pollutants, and
improving the photocatalytic oxidation degradation efficiency. Active
species of trapping experiments showing photocatalytic degradation
of active species as h+, ·O2–, and
·OH do not act as active species for MO degradation in this system.
ATS NCs have ultra-high photocatalytic activity and further improve
their photocatalytic efficiency by partially coated ZnS shells. Finally,
we present the mechanism of photocatalytic degradation of ATS NCs
and analyze the possible applications of ATS NCs. Due to its unique
advantages of direct synthesis in organic pollutants at room temperature,
it is expected to achieve a breakthrough in the practical treatment
of large-scale industrial wastewater.