Heterostructured Bi₃O₄Br/α-Bi₂O₃ nanocomposites are prepared via in situ one-step self-combustion of ionic liquids. Tetrabutylammonium bromide (TBAB) is employed to be fuel, complexing agent for ionic liquids, as well as the reactant supplying Br for the objective material. The ratio of Bi₃O₄Br/α-Bi₂O₃ can be easily adjusted by controlling the amount of TBAB. The heterojunctions show higher photocatalytic ability towards both azo dye methyl orange (MO) and colorless pollutant phenol. The electron spin resonance (ESR) test and p-nitro blue tetrazolium chloride (NBT) degradation result indicate that generation amounts of superoxide anion radicals (O₂⁻) over heterojunctions are less than that over pure Bi₃O₄Br. Photoelectrochemical measurements show that separation efficiencies of photo-generated electrons and holes are decreased after the combination of Bi₃O₄Br and α-Bi₂O₃. Work function test and scavenger experiments display that holes play key role for pollutant degradation and the position of holes on α-Bi₂O₃ is lowered via hybridization. Thus, the enhanced photocatalytic activity over composites can be attributed to the position decline of α-Bi₂O₃ valence band, thus improving the reactivity of holes in direct oxidation of pollutants. In this case, valence band position is confirmed to be more important than separation efficiency of charge carriers in affecting photocatalytic performance.

异质结构的Bi ₃ ö ₄比Br /α-Bi系_2个ö ₃纳米复合材料是通过制备在原位的离子液体一步法自燃。四丁基溴化铵（TBAB）被用作燃料，离子液体的络合剂以及目标物供应溴的反应物。Bi的比率₃ ö ₄比Br /α-Bi系₂ ö ₃可以通过控制TBAB的量轻松地进行调整。异质结对偶氮染料甲基橙（MO）和无色污染物苯酚显示出更高的光催化能力。电子自旋共振（ESR）测试和对-硝基蓝四唑氯化物（NBT）降解结果表明超氧化物阴离子自由基的那一代量（ö ₂ ^- ）上的异质结是小于在纯的Bi ₃ ö ₄溴。光电化学测量显示光产生的电子和空穴的分离效率是Bi的组合后降低₃ ö ₄ Br和α-Bi系₂ ö ₃。功函数测试和清除剂的实验显示孔发挥污染物降解关键作用和空穴的对α-Bi系的位置₂ ö ₃通过杂交被降低。因此，随着复合材料增强的光催化活性可以归因于α-Bi的位置下降₂ ö ₃价带，从而提高了污染物的直接氧化孔的反应性。在这种情况下，在影响光催化性能方面，价带位置被证实比电荷载流子的分离效率更重要。