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用电极反应方法实现水的光电分解,是利用太阳能的一条途经.但这一方法的主要障碍是能量转换效率低.原因之一是目前能用于光解水的大部分半导体材料的禁带宽度大,只能吸收太阳谱带中很小的一部分能量.例如,TiO_2的禁带宽度约为3电子伏,相应吸收波长小于413nm 的光子,其能量只占整个太阳能的3%左右.而一些禁带宽度比较小的半导体材料,如禁带宽度为1.43电子伏的GaAs,光照时,在电解液中易发生腐蚀溶解.寻找既能吸收长波方向的光子,在电解液中又比较稳定的半导体材料,提高能量转换效率,是一项有意义的探索.Fe_2O_3是一种有希望的材料,它的禁带宽度为2.2电子伏,相应吸收光的波长小于564nm,理论上可以利用整个太阳能的25%以上,在pH>4的电解液中是稳定的.自1976年K.L.Hardee 和A.J.Bard 报道了用CVD 法制得氧化铁光敏电极以来,相继又报道了单品α—Fe_2O_3半导体电极,金属热氧化法及压片烧结法等不同的制备方法及材料的光电化学性能.在本文中,我们试就Fe_2O_3 掺TiO_2经压片烧结后获得的电极,测试其光电响应,以期探讨杂质对Fe_2O_3电极的影响.
One of the main obstacles to achieving this photodecomposition of water by electrode reaction is the use of solar energy, but one of the major obstacles to this approach is the energy conversion efficiency, which is due to the forbidden band width of most semiconductor materials currently available for photolysis For example, the bandgap of TiO_2 is about 3 electron volts, and the corresponding absorption wavelength is less than 413nm photons, its energy is only about 3% of the total solar energy, while some ban For semiconductor materials with relatively small bandwidths, such as GaAs with a bandgap of 1.43 electron volts, it is prone to corrode and dissolve in the electrolyte when illuminated, looking for photons that absorb both long-wave and relatively stable semiconductor materials in the electrolyte , To improve the energy conversion efficiency is a meaningful exploration.Fe_2O_3 is a promising material with a forbidden band width of 2.2 eV and a corresponding absorbed light wavelength of less than 564 nm and can theoretically make use of 25% Above, stable at pH> 4. Since KLHardee and AJBard reported in 1976 that the iron oxide photodetector was prepared by CVD method, single-phase α-Fe_2O_3 semiconductor , Metal thermal oxidation and tableting sintering method and other different preparation methods and the photoelectrochemical properties of materials.In this paper, we try to Fe_2O_3 doped TiO_2 obtained by pressing the sintered electrode, the test of its photoelectric response, in order to explore the impurity pairs Fe_2O_3 electrode.