In the construction of metal-semiconductor heterojunction, rationally tuning the Schottky barrier has a significant influence on its catalytic activity. Herein, we have successfully constructed plasmonic Ag NPs on nitrogen-vacancy modified g-C₃N₄ nanotubes (ACNNT) through a facile in situ self-assembly strategy for realizing high visible-light photocatalytic CO₂ conversion. Benefiting from uniform distribution of Ag NPs and spatially directed separation and migration of 1D tubular g-C₃N₄ architecture, the plasmonic metal utilization efficiency can be significantly enhanced. The ACNNT catalyst exhibits a superior CO evolution rate of 88.2 μmol g⁻¹ h⁻¹ under visible light irradiation, more than 10.9 times higher than BCN. DFT calculations combined with experimental studies demonstrate that the introduced nitrogen vacancy can alter the Schottky barrier at the interface and simultaneously diminish the energy barrier for CO₂ activation. Therefore, the optimized Schottky barrier height not only accelerate charge kinetics via the driving force from the Schottky junction, but also prevent the photoelectrons trapped by Ag from flowing back to g-C₃N₄ under visible light, which effectively inhibit the photoinduced charge carrier recombination, thus contributing to more efficient CO₂ photoreduction. This work reveals a key insight on the construction of carbon nitride-based Schottky heterojunction in the field of photocatalytic CO₂ reduction.

在金属-半导体异质结的构建中，合理调整肖特基势垒对其催化活性有显着影响。在此，我们通过简便的原位自组装策略成功地在氮空位修饰的gC ₃ N ₄纳米管（ACNT）上构建了等离子体Ag NPs，以实现高可见光光催化CO ₂转化。_{得益于Ag NPs的均匀分布和一维管状gC 3} N ₄结构的空间定向分离和迁移，等离子体金属的利用效率可以显着提高。ACNT 催化剂表现出优异的 CO 析出率，为 88.2 μmol g ^-1 h ^-1在可见光照射下，比 BCN 高 10.9 倍以上。DFT计算结合实验研究表明，引入的氮空位可以改变界面处的肖特基势垒，同时降低CO ₂活化的能垒。因此，优化后的肖特基势垒高度不仅可以通过肖特基结的驱动力加速电荷动力学，而且可以防止被Ag捕获的光电子在可见光下回流到gC ₃ N ₄ ，从而有效抑制光致载流子复合，从而有助于提高 CO _2的效率光还原。_{这项工作揭示了在光催化 CO 2}还原领域中构建基于氮化碳的肖特基异质结的关键见解。