An innovative tactic is to architecture novel p–n junctions for the efficient separation of charge carriers at heterojunction interfaces and enhance the photocatalytic activity under visible light irradiation. In view of this, we have fabricated a novel CuO/PbTiO₃ p–n junction by a simple impregnation method and examined its photocatalytic activity towards the degradation of malachite green. First and foremost, the photoelectrochemical measurements confirmed the n-type and p-type semiconducting properties of PbTiO₃ and CuO, respectively. The measured asymmetric photocurrent in opposite directions and the rectifying behaviour of all the prepared heterojunctions confirmed the formation of a p–n junction between the CuO and PbTiO₃. The TEM results reveal that the p-type CuO nanoparticles were successfully assembled on the surface of the polyhedron-shaped n-type PbTiO₃ and a strong p–n junction interface was formed between them. A regular study is represented for the detailed characterization of the phases, surface chemical composition, surface morphology, and optical properties of the prepared heterojunctions. All the CuO/PbTiO₃ p–n junctions exhibited superior photocatalytic activity for the degradation of malachite green (MG) under visible light irradiation compared to neat PbTiO₃ and CuO. The superior photocatalytic activity of the p–n junction samples was due to the efficient separation of charge carriers at the junction interface. The efficient separation of charge carriers at the p–n junction interface was confirmed by EIS, steady state, and time-resolved PL analysis. The 33% CuO/PbTiO₃ p–n junction reveals a higher activity around 91% degradation of malachite green under visible light irradiation in comparison to the other p–n junctions. The kinetic analysis of the prepared photocatalysts for malachite green (MG) degradation showed that the process followed a pseudo-first-order kinetics model.

中文翻译：

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CuO / PbTiO ₃：一种新型的p–n结，设计用于有效吸收可见光，并具有增强的界面电荷转移，光电化学和光催化活性

一种创新策略是构建新颖的p–n结，以有效分离异质结界面处的载流子，并增强可见光照射下的光催化活性。有鉴于此，我们通过简单的浸渍方法制备了新型的CuO / PbTiO ₃ p–n结，并研究了其对孔雀石绿降解的光催化活性。首先，光电化学测量结果分别证实了PbTiO ₃和CuO的n型和p型半导体性能。在相反方向上测量的不对称光电流以及所有制备的异质结的整流行为证实了CuO和PbTiO ₃之间的ap–n结的形成。TEM结果表明，p型CuO纳米颗粒已成功组装在多面体形状的n型PbTiO ₃的表面上，并且在它们之间形成了牢固的p–n结界面。常规研究代表了所制备异质结的相，表面化学组成，表面形态和光学性质的详细表征。与纯PbTiO ₃相比，所有CuO / PbTiO ₃ p–n结在可见光照射下均表现出对孔雀石绿（MG）降解的优异光催化活性。和CuO。p–n结样品的优异光催化活性是由于在结界面处有效分离了载流子。EIS，稳态和时间分辨的PL分析证实了p–n结界面处载流子的有效分离。与其他p-n连接相比，在可见光照射下33％的CuO / PbTiO ₃ p-n连接显示出约91％的孔雀石绿降解性能。所制备的用于孔雀石绿（MG）降解的光催化剂的动力学分析表明，该过程遵循伪一级动力学模型。