Efficient Photocatalytic Conversion H ₂ S to H ₂ and Na ₂ S ₂ O ₃ Over Ni ₃ S ₄ /Cd _0.5 Zn _0.5 S Schottky Junction in NaOH/Na ₂ SO ₃ Solution

ABSTRACT The photo‐driven conversion of toxic hydrogen sulfide (H ₂ S) waste gas into hydrogen (H ₂ ) and high‐value sulfur‐containing chemicals is of great significance to the coal chemical and petrochemical industries. In this paper, Ni ₃ S ₄ with excellent electrical conductivity was loaded on the surface of Cd _0.5 Zn _0.5 S (CZS) solid solution to construct a Ni ₃ S ₄ /CZS interfacial Schottky junction photocatalyst. The research shows that Ni ₃ S ₄ significantly improves the charge separation efficiency on the substrate surface. Using the saturated solution obtained by absorbing H ₂ S with 0.2 mol L ⁻¹ (M) NaOH and 0.6 M Na ₂ SO ₃ as the reaction solution, the H ₂ production rate of the 2 wt.% Ni ₃ S ₄ /CZS composite can reach 171.3 mmol g ⁻¹ h ⁻¹ . Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy confirmed that the sulfur compounds in the reaction solution were almost completely converted into Na ₂ S ₂ O ₃ . The above Schottky junction composite provides an important experimental reference for the development of an efficient H ₂ S photocatalytic conversion system and the simultaneous production of H ₂ and Na ₂ S ₂ O ₃ .