Synthesis And Photocatalytic CO₂ Reduction Performance Of Water-stable Bismuth-halogen Hybrid Semiconductive Materials

In recent years,lead-based hybrid metal halide APbX₃（A=organic cation,X=halogen）has become a research hotspot in synthetic chemistry and materials science due to its excellent catalytic performance and low price.However,poor water stability and lead toxicity issues hinder the practical application of lead-based hybrid metal halides.In this paper,non-toxic bismuth halides were used as inorganic components,and benzothiazole derivatives were used as organic components.The organic components were modified by in-situ alkylation reaction,and a series of bismuth with high water stability were obtained.based hybrid metal halide materials,and the photocatalytic CO₂ reduction performance of the prepared materials was studied,and the results are as follows:1.Using the"non-hydrogen bond"strategy to design and synthesize three bismuth-based hybrid halide materials with zero-dimensional structure,propylbenzo[d]thiazol-3-ium)₃Bi₂I₉,（3-butylbenzo[d]thiazol-3-ium）₃Bi₂I₉ and（3-isobutylbenzo[d]thiazol-3-ium）₂Bi₂I₉·C₄H₁₂O₂are abbreviated as Probt-Bi₂I₉,Bubt-Bi₂I₉ and Iso Bubt-Bi₂I₉,respectively.All three examples of materials contain dinuclear bismuth iodide anions and alkylated benzothiazole"non-hydrogen bond"cations.Water stability studies showed that the three compounds could exist stably for more than 30 days under 75%relative humidity and 254 nm ultraviolet light irradiation,showing significantly enhanced water stability compared with MA₃Bi₂I₉（MA=CH₃NH₃⁺）material.The performance test shows that the three compounds have good photocatalytic reactivity,and can realize the effective catalysis of CO₂ to CO in the pure water reaction system.2.By introducing halogen and amino groups to modify methylbenzothiazole counter cations,three examples of one-dimensional bismuth-based hybrid halide materials were synthesized,which were（3-methylbenzo[d]thiazol-3-ium）Bi I₄,（5-bromo-3-methylbenzo[d]thiazol-3-ium）Bi I₄ and（2-amino-3-methylbenzo[d]thiazol-3-ium）Bi I₄,respectively abbreviated as Mebt-Bi I₄,5-Br Mebt-Bi I₄ and 2-Am Mebt-Bil₄.All three compounds contain one-dimensional bismuth iodide anion chains and alkylated benzothiazole"non-hydrogen bond"cations.Stability studies show that the compound still maintains excellent water,heat and light stability after the introduction of halogen or amino groups.Because the introduction of halogen and amino groups provides more binding sites with water in the reactant,the photocatalytic activity is significantly improved.3.Based on the synthesis strategy of Experiment 1,by changing the halogen species in the inorganic components,two bismuth-based hybrid halide materials were synthesized,namely（3-methylbenzo[d]thiazol-3-ium）4Bi2Br10 and（3-methylbenzo[d]thiazol-3-ium）Bi Cl4,respectively abbreviated as Mebt-Bi2Br10 and Mebt-Bi Cl4.The two compounds contain（Bi2Br10）4-binuclear and（Bi Cl4）-one-dimensional chain anions,respectively,both of which use alkylated "hydrogen bond-free" cations as counter ions.The changes in the elements and structures of the inorganic components in the two compounds have realized the adjustment of the light absorption,band gap width and energy band structure of the material.Both compounds exhibited effective photocatalytic CO₂ reduction activity as well as good catalytic reproducibility and stability.In this paper,the synthesis,stability,photocatalytic CO₂ reduction performance and efficiency optimization of the three systems of hybrid bismuth halogen compounds were studied in depth.The prepared hybrid bismuth halogen photocatalysts can be realized in pure water or aqueous reaction systems.The effective catalytic conversion of CO₂ overcomes some shortcomings in the existing research on the photocatalytic performance of hybrid metal halides,such as poor water stability of materials and lack of effective hydrophilic site control strategies.The obtained research results not only provide good hybrid lead-free photocatalysts for the field of CO₂ reduction,but also provide a general synthetic strategy for water-stable bismuth-based hybrid semiconductor catalysts.