Research On Cadmium Manganous(Zinc) Sulfide-based Composite Materials For Hydrogen Production From Water

Photocatalytic water splitting to produce H₂ has been considered as one of economically and environmentally friendly strategies to alleviate energy crises and reduce environmental pollutions.Researchers have been working on developing highly active catalysts.Cadmium manganous（zinc）sulfide has attracted cumulative attention in the field of photocatalytic H₂evolution owing to its flexible bandgap.Nevertheless,the fact that charge carriers recombine rapidly still needs a critical factor and limits the hydrogen-generating performance.Here,we synthesized a series of cadmium manganous（zinc）sulfide-based composite materials.It reduces the charge carrier recombination in the composites leading to higher photocatalytic hydrogen activity.The main contents are as follow:1.CoWO₄/Mn_0.47Cd_0.53S composites were synthesized based on a facile solvothermal method.A p-n heterojunction is formed between CoWO₄ and Mn_0.47Cd_0.53S,it displays an excellent anti-photocorrosion and promising hydrogen evolution performance up to 41.53mmol·g^-1·h^-1 under the condition of Na₂S/Na₂SO₃ as sacrifice reagent,which is 2.68-fold higher than pure MCS.The loading of CoWO₄efficiently inhibits the photoelectron-hole recombination and reduced the charge transfer resistance,thus facilitates the photocatalytic process.2.The W₁₈O₄₉/Mn_0.45Cd_0.55S composites were synthesized by a two-step solvothermal method.Using Na₂S/Na₂SO₃ as a sacrificial agent,the hydrogen production rate could reach32.47 mmol·g^-1·h^-1.The construction of S-type heterojunction enables electrons and holes that do not participate in redox reactions to be consumed,more photogenerated electrons are retained,realizing the spatial separation of photoelectron-hole and improving the hydrogen production activity.3.Cu₂Mo S₄/Zn_0.44Cd_0.56S composites were synthesized by a two-step solvothermal method.The transition metal sulfide Cu₂Mo S₄ was used as a cocatalyst to enhance the absorption of visible light.The tight bond between Cu₂Mo S₄ and Zn_0.44Cd_0.56S promotes the transfer of carriers.Under visible light irradiation,using 10 vol%lactic acid as a sacrificial agent,the optimal hydrogen production rate is 48.65 mmol·g^-1·h^-1,which is 2.9 times that of Zn0.44Cd0.56S.