In this paper, an ultrathin 2D/2D Ti₃C₂/g-C₃N₄ heterojunction was synthesized by direct calcination the mixture of bulk Ti₃C₂ and urea, where urea not only acts as the gas template to exfoliate Ti₃C₂ into nanosheets, but also as the precursor of g-C₃N₄ to craft Ti₃C₂/g-C₃N₄ heterojunction. CO₂ photoreduction activity tests reveal that pure g-C₃N₄ (UCN) exhibits very weak photoactivity. However, when Ti₃C₂ was coupled with g-C₃N₄, the photocatalytic performance is soaringly enhanced. The optimal sample (10TC) shows the yields of 5.19 and 0.044 µmol h⁻¹ g⁻¹ for CO and CH₄, respectively, and the total CO₂ conversion is 8.1 times higher than that of UCN. The enhanced CO₂ photoreduction activity is mainly attributed to the combined effects of (1) improved CO₂ adsorption and activation, and (2) the construction of ultrathin 2D/2D Ti₃C₂/g-C₃N₄ heterojunction, where the intimate contact stimulates an efficient spatial separation of photo-excited charge carriers.

本文通过直接煅烧大量的Ti ₃ C ₂和尿素的混合物来合成超薄的2D / 2D Ti ₃ C ₂ / gC ₃ N ₄异质结，其中尿素不仅充当剥离Ti ₃ C ₂的气体模板制成纳米片，也可以作为gC ₃ N ₄的前体来制备Ti ₃ C ₂ / gC ₃ N ₄异质结。CO _2光还原活性测试表明，纯gC ₃ N ₄（UCN）表现出非常弱的光活性。但是，当Ti₃ C ₂与gC ₃ N _4结合，光催化性能急剧提高。最佳样品（10TC）显示，CO和CH ₄的产率分别为5.19和0.044 µmol h ^-1  g ^-1，总的CO ₂转化率是UCN的8.1倍。CO _2的光还原活性增强主要归因于（1）改善的CO ₂吸附和活化，以及（2）超薄2D / 2D Ti ₃ C ₂ / gC ₃ N _{4的组合。} 异质结，其中紧密接触可激发光激发载流子的有效空间分离。