中文摘要：

使用相分离的水解-溶剂热法制备了α-Fe2O3纳米粒子,通过简单的湿化学法实现了质量分数为3%的石墨烯、氮掺杂石墨烯和g-C3N43种二维异质体对纳米α-Fe2O3的复合改性,并比较了3种二维异质体对α-Fe2O3光催化活性的影响.结果表明,在光催化还原二氧化碳和降解液相苯酚过程中,二维异质体的复合均提高了纳米α-Fe2O3的光催化活性,氮掺杂石墨烯对α-Fe2O3的改性效果优于石墨烯,其中g-C3N4对α-Fe2O3的改性效果最优.通过表面光电压谱、光电化学及羟基自由基等测试,确认二维异质体的复合改性主要通过促进纳米α-Fe2O3的光生电荷分离和提高活性中间组分（羟基自由基）的含量提高纳米α-Fe2O3的光催化活性.

英文摘要：

Alpha iron-trioxide（ α-Fe2O3） nanoparticles were synthesized by a phase-separated hydrolysissolvothermal method,and then modified by coupling 3%（ mass fraction） graphene,nitrogen-doped graphene and g-C3N4 as the two-dimensional hetero-materials by a simple wet chemical process. Detailed comparative studies of their effects on photocatalytic activities of α-Fe2O3 were carried out. The results show that the photocatalytic activities of nano α-Fe2O3 for reducing CO2 to CO and for degrading phenol are enhanced after coupling with all two-dimensional hetero-materials. The modification of nitrogen-doped graphene on α-Fe2O3 is better than graphene and the modification of g-C3N4 on α-Fe2O3 is the best. Based on the measurements of surface photovoltage responses,photoelectrochemical curves,and hydroxyl radical amounts,it is confirmed that the introduction of two-dimensional hetero-materials would promote the photogenerated charge separation and increase the content of the active intermediate（ hydroxyl radicals） consequently,leading to the improved photocatalytic activity of nano α-Fe2O3.