The invention provides a process for generating a metal sulphide comprising nickel and/or cobalt, comprising the steps of: i. forming an aqueous metal sulphate solution by reacting sulphuric acid with a raw material feed comprising nickel and/or cobalt in water; ii. crystallizing said metal sulphate from said aqueous metal sulphate solution to form a crystallized metal sulphate in a mother liquor, the mother liquor comprising an uncrystallized metal sulphate; iii. separating said crystallized metal sulphate from said mother liquor; iv. reacting at least a portion of said uncrystallized metal sulphate with hydrogen sulphide in an acidic aqueous medium, thereby obtaining a slurry consisting of a solid phase comprising a metal sulphide precipitate and an aqueous phase comprising one or more impurities and sulphuric acid; and v. separating said solid phase and said aqueous phase.

A method for preparing a cobalt sulfide/reduced graphite oxide composite includes: preparing a glycerol-cobalt precursor by taking a water-soluble cobalt salt, a micromolecular alcohol solvent, and glycerol as raw materials; mixing the glycerol-cobalt precursor with an alkali liquor to prepare a Co(OH).sub.2 nanoflower; calcining the Co(OH).sub.2 nanoflower to obtain a Co.sub.3O.sub.4 nanoflower; subjecting the Co.sub.3O.sub.4 nanoflower to a reaction with a water-soluble sulfur salt to obtain a COS nanoflower, and mixing the COS nanoflower with graphite oxide and carrying out a heat treatment to obtain the composite. The response characteristics of a gas sensor to NO.sub.2 gas are studied at room temperature, and the graphite is complexed with a transition metal sulfide with unique morphology to construct a unique heterostructure. While expanding the specific surface area to increase the number of adsorption sites, the heterostructure of a contact surface is used to greatly enhance the charge-transfer efficiency.

A method for preparing a cobalt sulfide/reduced graphite oxide composite includes: preparing a glycerol-cobalt precursor by taking a water-soluble cobalt salt, a micromolecular alcohol solvent, and glycerol as raw materials; mixing the glycerol-cobalt precursor with an alkali liquor to prepare a Co(OH).sub.2 nanoflower; calcining the Co(OH).sub.2 nanoflower to obtain a Co.sub.3O.sub.4 nanoflower; subjecting the Co.sub.3O.sub.4 nanoflower to a reaction with a water-soluble sulfur salt to obtain a COS nanoflower, and mixing the COS nanoflower with graphite oxide and carrying out a heat treatment to obtain the composite. The response characteristics of a gas sensor to NO.sub.2 gas are studied at room temperature, and the graphite is complexed with a transition metal sulfide with unique morphology to construct a unique heterostructure. While expanding the specific surface area to increase the number of adsorption sites, the heterostructure of a contact surface is used to greatly enhance the charge-transfer efficiency.

The present invention relates to the field of renewable energy and photocatalysis (e.g. photocatalytic water splitting for hydrogen production), specifically focusing on sulfurized perovskite compounds, perovskite nanosheets, and synthesis method and uses thereof. The present invention relates to perovskite nanosheets comprising LaXO.sub.nS.sub.3-n, wherein X is a metal selected from Fe, Co, Mn, Cu, Zn, or Ni; and wherein 0<n<3. Further, the present invention explores the perovskite nanosheets to improve efficiency, stability, and light absorption in solar-driven hydrogen generation applications. The present perovskite nanosheet enhances visible light absorption, charge carrier mobility, and catalytic activity, making it useful for large-scale hydrogen production.

The present invention relates to the field of renewable energy and photocatalysis (e.g. photocatalytic water splitting for hydrogen production), specifically focusing on sulfurized perovskite compounds, perovskite nanosheets, and synthesis method and uses thereof. The present invention relates to perovskite nanosheets comprising LaXO.sub.nS.sub.3-n, wherein X is a metal selected from Fe, Co, Mn, Cu, Zn, or Ni; and wherein 0<n<3. Further, the present invention explores the perovskite nanosheets to improve efficiency, stability, and light absorption in solar-driven hydrogen generation applications. The present perovskite nanosheet enhances visible light absorption, charge carrier mobility, and catalytic activity, making it useful for large-scale hydrogen production.