Johannes BirkenstockSuman Pokhrel; Jakob Stahl; Lizhuo Wang; Rui Tang; Haoyue Sun; Malte Schalk; Marco Schowalter; Andreas Rosenauer; Jun Huang; Johannes Kiefer; Johannes Birkenstock; Lutz Mädler

Advanced Functional Materials 35 (2024)

doi: 10.1002/adfm.202411521

The innovative development of reactive-spray systems for gas-phaseproduction of metal sulfides are potential materials for next-generationtechnologies. These flame-synthesized sulfides (doped, functionalized, andheterogeneously mixed derivatives) hold significant potential as photocatalystsfor water splitting. The knowledge acquired from nonaqueous precursor-solvent and high-temperature aerosol chemistries, optimal process parametersare established to generate In 2-(4/3)x Snx S3 , solid-solutions. The thermally drivenreducing gas-phase reactions are controlled through fuel/oxygen ratio. Particlescharacterizations (X-ray diffraction, transmission electron microscopy (TEM)and imaging) revealed structural stability and crystallinity. The In2-(4/3)x Snx S3 ,at higher Sn doping had enhanced photoexcitation. Donor-acceptor levelswithin the material facilitated electron-hole pair trapping, crucial for redoxreactions. With suitable band gap energies for water oxidation (1.9-1.1 eV)closely matched flat band potentials (4.38-4.67 eV) for redox reactions. Thepowder characterization showed 8% In 2 O3 in InSn0.75 S3 after photocatalysisdue to S-degradation in the initial light “on/off cycles”. The pioneeringprocess of employing oxygen-deficient reducing flame enabled a seriesof photo-catalytically active metal sulfide nanoparticles with work functionenergies in the range of 5.19-5.37 eV. This synthesis strategy holds the potentialfor impactful advancements in both industry and R&D, addressing the urgentneed for new materials capable of inducing water oxidation under visible light.

© 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH