【作者】 周丽；

【导师】 真嶋哲朗（MAJIMA Tetsuro）； 王楠；

【作者基本信息】 华中科技大学 ， 分析化学， 2022， 硕士

【摘要】 半导体材料光催化分解水制氢将光能转化为清洁能源氢能,已成为解决能源危机与环境问题的有效手段。作为层状结构的三元金属硫族化物,硫化铟锌（ZnIn₂S₄）具有较窄的带隙,可用于可见光下光催化产氢。但由于其光生电子-空穴易复合,光催化产氢量子效率不高。将ZnIn₂S₄与其他材料复合,可有效提高其电子-空穴对的分离与传递效率。鉴于此,本论文构建了基于ZnIn₂S₄的两种复合材料,探究其光催化产氢性能,主要研究结果如下:（1）选用金属酞菁（MPc）与ZnIn₂S₄复合,构建了系列ZnIn₂S₄/MPc复合催化剂（M=Zn、Ni、Mg、Fe、Co、H）,并探究了不同金属酞菁对复合物产氢性能的影响。结果显示:与ZnIn₂S₄相比,ZnIn₂S₄/MPc均具有更强的光催化产氢性能,其产氢速率按如下顺序递增:ZnIn₂S₄<ZnIn₂S₄/Co Pc<ZnIn₂S₄/H₂Pc<ZnIn₂S₄/Fe Pc<ZnIn₂S₄/Mg Pc<ZnIn₂S₄/Ni Pc<ZnIn₂S₄/Zn Pc,其中ZnIn₂S₄/0.5%-Zn Pc产氢速率最佳,可达到1176.9μmol·g^–1·h^–1,是纯ZnIn₂S₄的9.4倍。采用多种光谱及电化学分析手段阐明了MPc的增效机制:ZnIn₂S₄/MPc复合催化剂受光激发后,MPc的最高占有轨道（HOMO）上的电子跃迁至最低空轨道（LUMO）,进而转移至ZnIn₂S₄导带,用于还原水产氢;而ZnIn₂S₄价带的光生空穴则转移至MPc的HOMO轨道,从而实现了光生载流子在空间的有效分离,故MPc负载提高了ZnIn₂S₄的光催化产氢性能;此外,金属酞菁自身的光吸收能力及LUMO轨道位置是影响光生电子数量的关键因素。（2）采用磷化二钴（Co₂P）作为助催化剂,乙二胺（EDA）作为桥连剂,构筑了ZnIn₂S₄/EDA/Co₂P复合催化剂,并探究了其光催化产氢性能。结果显示:当Co₂P/ZnIn₂S₄与EDA/ZnIn₂S₄的质量比分别为12.5%和0.5%时,制得的ZnIn₂S₄/EDA/Co₂P异质结催化剂的产氢活性最佳,高达2324.1μmol·g^–1·h^–1,分别约为ZnIn₂S₄/Co₂P和ZnIn₂S₄的1.7倍和18倍。Zeta电位及光电化学等表征结果表明,Co₂P复合可增强ZnIn₂S₄的光吸收能力及电荷分离效率,但二者的等电点均在p H2以下,在近中性的水中,其表面带负电荷,不利于紧密接触;采用两个端基带正电荷的乙二胺(p K_a1=9.9)为桥连剂可显著增强Co₂P和ZnIn₂S₄之间的界面作用,极大地促进了光生电子与空穴的迁移与分离,从而进一步提高ZnIn₂S₄/Co₂P的光催化产氢性能。更多还原

【Abstract】 Semiconductor-based photocatalytic hydrogen evolution from water splitting can convert solar energy into clean hydrogen energy,which is considered as the promising technology to solve the energy crisis and environmental problems.As a layered structure ternary metal chalcogenide,zinc indium sulfide（ZnIn₂S₄）has a narrow band gap and can be used for photocatalytic hydrogen evolution under visible light.However,due to the fast recombination of photogenerated electrons and holes,the quantum efficiency of ZnIn₂S₄ for photocatalytic hydrogen evolution is not high.Combining ZnIn₂S₄ with other materials can effectively improve charge separation and transfer efficiency.Therefore,in this thesis,two kinds of ZnIn₂S₄-based composites were constructed,and their application in photocatalytic hydrogen evolution were studied in detail.The main research results are as follows:（1）A series of metal phthalocyanines（MPc;M=Zn,Ni,Mg,Fe,Co,H）were used to combine with ZnIn₂S₄ for the preparation of ZnIn₂S₄/MPc composite catalysts.The ZnIn₂S₄/MPc composites were applied in photocatalytic hydrogen evolution to explore the effect of different MPc on the hydrogen evolution activity.The results showed that compared with ZnIn₂S₄,ZnIn₂S₄/MPc showed enhanced photocatalytic hydrogen evolution activity,and its hydrogen production rate increased in the following order:ZnIn₂S₄<ZnIn₂S₄/Co Pc<ZnIn₂S₄/H₂Pc<ZnIn₂S₄/Fe Pc<ZnIn₂S₄/Mg Pc<ZnIn₂S₄/Ni Pc<ZnIn₂S₄/Zn Pc.Among them,ZnIn₂S₄/0.5%-Zn Pc showed the highest hydrogen evolution rate,which could reach 1176.9μmol·g^–1·h^–1,being 9.4 times than that of pure ZnIn₂S₄.The synergistic mechanism of MPc was elucidated by spectroscopic and electrochemical analysis methods.After the ZnIn₂S₄/MPc composite catalysts were excited by light,the electrons on the highest occupied molecular orbital（HOMO）of MPc transferred to its lowest unoccupied molecular orbital（LUMO）,and then transferred to the conduction band of ZnIn₂S₄,which were used to reduce water to produce hydrogen;while the photogenerated holes in the valence band of ZnIn₂S₄ transferred to the HOMO orbital of MPc,achieving the effective separation of photogenerated carriers in space.Thus,the introduction of MPc improved the photocatalytic hydrogen evolution activity of ZnIn₂S₄.Moreover,the light absorption ability of MPc and the position of LUMO orbital were the key factors affecting the number of photogenerated electrons.（2）Cobalt phosphide（Co₂P）was used as a cocatalyst and ethylenediamine（EDA）was used as a bridging agent to construct ZnIn₂S₄/EDA/Co₂P composites,which was then used in photocatalytic hydrogen evolution.The results showed that when the mass ratio of Co₂P/ZnIn₂S₄ and EDA/ZnIn₂S₄ were 12.5%and 0.5%,respectively,the prepared ZnIn₂S₄/EDA/Co₂P heterojunction catalyst showed the highest hydrogen evolution activity,which could reach 2324.1μmol·g^–1·h^–1,being about 1.7 and 18 times than that of ZnIn₂S₄/Co₂P and ZnIn₂S₄,respectively.The characterization results of zeta potential and photoelectrochemistry showed that Co₂P could enhance the light absorption capacity and charge separation efficiency of ZnIn₂S₄,but their isoelectric points were below p H 2 to have negatively charged surface in near-neutral water,which was not beneficial for their close contact.Ethylenediamine(p K_a1=9.9)with two positively charged terminal groups as a bridging agent could significantly enhance the interfacial interaction between Co₂P and ZnIn₂S₄,which greatly promoted the migration and separation of photogenerated electrons and holes,thereby improving the photocatalytic hydrogen evolution activity of ZnIn₂S₄/Co₂P.更多还原