In this study, novel and noble metal-free copper nickel oxysulfide (CuNiOS) nanoparticles have been successfully fabricated by using a simple, cost-effective, and eco-friendly solution-based approach, with copper oxysulfide (CuOS) as a comparative. The CuOS and CuNiOS catalysts with various Ni contents were investigated by different techniques. The catalytic activities of the samples were assessed by the catalytic reduction of organic dyes such as 4-nitrophenol (4-NP), methylene blue (MB), and rhodamine-B (RhB) together with NaBH₄ in an aqueous solution. The results obtained from ultraviolet-visible (UV-vis) spectroscopy indicated that CuNiOS-0.6 prepared with a Cu : Ni precursor mole ratio of 1 : 0.6 had the best catalytic performance for the reduction of 4-NP, MB, and RhB in comparison to the other CuNiOS catalysts and the monometallic catalyst (CuOS) due to synergistic effects. In addition, the CuNiOS-0.6 catalyst is also better than other CuNiOS ones due to the presence of optimum amounts of Ni in the CuNiOS sample. Thus, the present approach provides a promising way to fabricate different noble metal free bimetallic oxysulfide catalysts for extensive applications in catalysis and reduction/removal of other organic pollutants.

A novel Cu V OS catalyst was successfully synthesized by a facile method. The Cu V OS with optimum amount of N ₂ H ₄ had higher catalytic activity.

A novel Ce/S co-doped TiO₂ sulfur-oxide catalyst (labeled TiCeOS) with heterovalent metal states and oxygen-vacancy defects was synthesized for effective photocatalytic nitrogen fixation into ammonia under visible light.

A CuO/TiO₂ photocatalyst was synthesized by using a hydrolysis method. In the synthesis, the Eichhornia crassipes accumulated with copper was used and combined with titanium chloride precursor.

The existence of a heterojunction in the catalyst structure improves the efficiency of photocatalytic hydrogen production. The two phases of the heterojunction can be adjusted simultaneously by doping sulfur and oxygen to achieve a suitable energy band structure. Herein, we demonstrated a Mo(S,O)/Co(O,S) Z-scheme heterojunction catalyst system (abbreviated as MoCoOS) with different Co(O,S) doping amounts by a simple one-step method. Doping of different atoms in the crystal changes the energy band structure which tunes the optical, electrical, and electrochemical properties of MoCoOS. MoCoOS-2 prepared at a Co precursor content of 20 mmol performed the best at a rate of 153.4 μmol h⁻¹ in photocatalytic hydrogen evolution, and it also showed excellent catalytic activities and good stability in reducing MO, MB, RhB, 4-NP and Cr⁶⁺. This efficient MoCoOS-2 catalyst can have practical applications in photocatalytic hydrogen production and catalytic reduction of chemical pollutants.