In this work, BiOBr-BiOI nano photocatalysts with different ratios were synthesized and evaluated under simulated sunlight for the removal of methylene blue (MB). BiOBr-BiOI with a 1:3 ratio removed 97 % of methylene blue, which was the highest removal percentage among the studied samples. The as-prepared photocatalysts were analyzed by XRD, BET-BJH, FESEM, UV–Vis DRS, and PL techniques. According to XRD, in all samples, BiOI and BiOBr crystals were present and the formation of a heterojunction was confirmed. FESEM indicated that the nanolayers of BiOI and BiOBr have been agglomerated in the form of flower-like micronized spheres. DRS analysis showed that BiOBr-BiOI (1:3) had a bandgap energy of 2.46 eV, between the bandgap energies of BiOBr and BiOI. To determine the suitable operating conditions, various operational parameters were examined using BiOBr-BiOI (1:3) and it was found that photocatalyst loading of 1 g/L, initial MB concentration of 5 ppm, and pH = 7, led to the maximum MB conversion. In the next phase, BiOBr-BiOI (1:1), which had the least activity in the degradation of MB, was subjected to plasma to investigate the effect of plasma on photocatalysts with ill-defined structure and low activity. Different voltages as well as different discharge durations were applied to this sample. Analyses confirmed that the size of the clusters, and the roughness of surfaces have declined after plasma treatment. Moreover, plasmonic Bi particles were formed which enhanced the light absorption and decreased charge carrier recombination which all resulted in a rise in the MB photocatalytic conversion from 40 % to 93 %.

在这项工作中，合成了不同比例的BiOBr-BiOI纳米光催化剂，并在模拟阳光下评估了亚甲基蓝（MB）的去除效果。 BiOBr-BiOI以1:3的比例去除了97%的亚甲基蓝，这是研究样品中去除率最高的。通过 XRD、BET-BJH、FESEM、UV-Vis DRS 和 PL 技术对所制备的光催化剂进行了分析。根据XRD，在所有样品中都存在BiOI和BiOBr晶体，并且证实了异质结的形成。 FESEM 表明 BiOI 和 BiOBr 纳米层以花状微粉化球体的形式团聚。 DRS分析表明BiOBr-BiOI (1:3)的带隙能量为2.46 eV，介于BiOBr和BiOI的带隙能量之间。为了确定合适的操作条件，使用 BiOBr-BiOI (1:3) 检查了各种操作参数，发现光催化剂负载量为 1 g/L，初始 MB 浓度为 5 ppm，pH = 7，可达到最大MB 转换。在下一阶段中，对MB降解活性最低的BiOBr-BiOI (1:1)进行等离子体处理，以研究等离子体对结构不明确且活性低的光催化剂的影响。对该样品施加不同的电压以及不同的放电持续时间。分析证实，等离子处理后团簇的尺寸和表面粗糙度均有所下降。此外，等离子体Bi颗粒的形成增强了光吸收并减少了载流子复合，从而使MB光催化转化率从40%提高到93%。