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由于人类面临的能源危机与环境污染问题日益严重,光催化技术作为最有可能解决这两大问题的技术而备受关注.其中,光催化剂是光催化技术的核心.开发具有宽光谱响应、高载流子分离效率的光催化剂既是研究热点也是难点.铋系光催化剂具有较强的可见光吸收能力.但是,提高铋系光催化剂对入射光的吸收效率、降低光生载流子复合效率仍是提高其光催化活性的关键.目前主要通过以下策略来解决这些问题:(1)贵金属负载,(2)半导体复合,(3)金属/非金属掺杂,(4)碳材料修饰,(5)铋金属负载等.最后还简要探讨了具有异质结的铋系光催化剂的发展趋势及其潜在应用.采用贵金属负载于铋系光催化剂(构建肖特基结),可以通过等离子体共振效应拓宽铋系光催化剂的光吸收范围,同时贵金属还能有效转移半导体上的光生电子,促进光生载流子的有效分离.但是,采用贵金属负载存在昂贵、容易发生团聚等不足.通过半导体之间构建紧密异质结,不仅可以调节所制备复合催化剂的能带结构,满足不同光催化反应的要求,而且由于内电场的存在可以促进光生载流子定向转移,从而提高光生载流子的分离效率.除此之外,通过杂原子掺杂可以在原子层面上构建异质结结构,也能有效抑制光生载流子的复合.近年来,通过与具有较好导电性能的碳材料复合,可以快速转移铋系半导体上产生的光子,提高光催化剂的活性和量子效率.铋纳米颗粒具有与贵金属类似的性能,通过采用铋金属对铋系半导体进行负载也可以发生等离子体共振效应,从而可以提高铋系半导体的活性.最后,作者展望了铋系半导体复合光催化剂发展的三个重要方向:(1)创制非化学计量比的铋系半导体复合光催化材料;(2)通过与还原能力更强的半导体构建复合光催化材料,实现光催化CO_2还原制备有机物和光催化全解水的应用中去;(3)充分利用铋系半导体化合物具有较强氧化能力的优点,将其应用于光催化有机物合成中,比如光催化甲苯类有机物选择性氧化等.
As human beings face the energy crisis and environmental pollution is worsening day by day, photocatalytic technology as the most likely to solve these two major problems of technology and much attention, of which photocatalyst is the core of photocatalytic technology.Developed with a wide spectral response, high Photocatalyst with carrier separation efficiency is not only a research hotspot but also a difficult one.Bismuth photocatalyst has a strong ability to absorb visible light.But improving the absorption efficiency of incident light by bismuth photocatalyst and reducing photo-carrier recombination efficiency are still increasing At present, these problems are mainly solved by the following strategies: (1) noble metal loading, (2) semiconductor recombination, (3) metal / nonmetal doping, (4) carbon material modification, Metal loading, etc. Finally, the development trends and potential applications of bismuth-based photocatalysts with heterojunction are briefly discussed.Using noble metal supported on bismuth photocatalyst (Schottky junction), bismuth can be broadened by the plasma resonance effect Department of light absorption of the photocatalyst range, while the precious metals can effectively transfer the photo-generated semiconductor on the semiconductor to promote the effective separation of photo-generated carriers However, the use of precious metals negative Which is expensive and prone to agglomeration.Construction of close heterojunction between semiconductors can not only adjust the energy band structure of the prepared composite catalyst to meet the requirements of different photocatalytic reactions but also promote the photo-current carrying because of the internal electric field In order to improve the separation efficiency of photogenerated carriers.In addition, the heterojunction structure can be constructed at the atomic level by heteroatom doping, and the recombination of photogenerated carriers can be effectively suppressed.In recent years, With the better conductivity of the carbon material composite, you can quickly transfer bismuth semiconductor photons produced to improve the photocatalytic activity and quantum efficiency of bismuth nanoparticles have a similar performance with precious metals, bismuth-based semiconductor by using bismuth-based semiconductor Load can also generate plasma resonance effect, which can improve the bismuth-based semiconductor activity.Finally, the author of the bismuth-based semiconductor composite photocatalyst development prospects of three important directions: (1) the creation of non-stoichiometric bismuth semiconductor composite light Catalytic material; (2) through the composite with stronger reducing power semiconductor photocatalytic material, to achieve photocatalytic CO_2 (3) taking full advantage of the strong oxidizing ability of bismuth-based semiconducting compounds, and applying them to the synthesis of photocatalytic organic compounds, such as selective photocatalytic oxidation of toluene-based organic compounds and the like .