The development of a facile strategy to construct stable hierarchal porous heterogeneous photocatalysts remains a great challenge for efficient CO₂ reduction. Additionally, hole-trapping sacrificial agents (e.g., triethanolamine, triethylamine, and methanol) are mostly necessary, which produce useless chemicals, and thus cause costs/environmental concerns. Therefore, utilizing oxidation ability of holes to develop an alternative photooxidation reaction to produce value-added chemicals, especially coupled with CO₂ photoreduction, is highly desirable. Here, an in situ partial phosphating method of In₂O₃ is reported for synthesizing InP–In₂O₃ p-n junction. A highly selective photooxidation of tetrahydroisoquinoline (THIQ) into value-added dihydroisoquinoline (DHIQ) is to replace the hole driven oxidation of typical sacrificial agents. Meanwhile, the photoelectrons of InP–In₂O₃ p-n junction can induce the efficient photoreduction of CO₂ to CO with high selectivity and stability. The evolution rates of DHIQ and CO are 2 and 3.8 times higher than those of the corresponding In₂O₃ n-type precursor, respectively. In situ irradiated X-ray photoelectron spectroscopy and electron spin resonance are utilized to confirm that the direct Z-scheme mechanism of InP–In₂O₃ p-n junction accelerate the efficient separation of photocarriers.

中文翻译：

---

在InP–In 2 O 3 Z方案pn结上集成光催化还原CO 2和四氢异喹啉的选择性氧化

构造稳定的分层多孔非均相光催化剂的简便策略的发展仍然是有效减少CO ₂的巨大挑战。另外，空穴捕获牺牲剂（例如，三乙醇胺，三乙胺和甲醇）是最必要的，其会产生无用的化学物质，从而引起成本/环境问题。因此，非常需要利用孔的氧化能力来进行替代的光氧化反应以产生增值的化学物质，特别是与CO _2光还原相结合。在这里，据报道In ₂ O _3的原位部分磷化方法用于合成InP–In ₂ O ₃pn结。四氢异喹啉（THIQ）的高选择性光氧化为增值二氢异喹啉（DHIQ）的作用是取代典型牺牲剂的空穴驱动氧化。同时，InP–In ₂ O ₃ pn结的光电子可以高选择性和高稳定性地将CO ₂有效还原为CO 。DHIQ和CO的释放速率分别比相应的In ₂ O ₃ n型前体的释放速率高2倍和3.8倍。利用原位辐照X射线光电子能谱和电子自旋共振来证实InP–In ₂ O ₃的直接Z方案机理 pn结加速了光载流子的有效分离。