Photocatalysis is regarded as a promising technology for removal of nitrogen oxide (NO), however, the low photocatalytic efficiencies under visible light irradiation and the deactivation of the photocatalyst are as yet the significant issues that should be addressed. In this work, visible-light-driven Bi₂Ti₂O₇/CaTiO₃ heterojunction composites were synthesized by a facile in-situ hydrothermal method. The Bi₂Ti₂O₇/CaTiO₃ composites displayed superior visible light photocatalytic activity than pure CaTiO₃ and pure Bi₂Ti₂O₇ in the removal of NO at the 600 ppb level in air. Among all the composites, Bi₂Ti₂O₇/CaTiO₃ containing 20 wt% Bi₂Ti₂O₇ exhibited the best photocatalytic activity, achieving a maximum removal efficiency of 59%. The improved photocatalytic performance is mainly attributed to the strong visible-light-absorbing ability, the presence of an appropriate density of oxygen vacancy defects and the formation of heterojunction between CaTiO₃ and Bi₂Ti₂O₇, resulting in an efficient charge separation at the interface as proven by photoluminescence (PL) and photo-induced current measurements. According to trapping experiments and spin-trapping ESR analysis, the ^•O₂⁻ and h⁺ are the principal reactive species involved in the photocatalytic NO removal. In addition, the as-obtained Bi₂Ti₂O₇/CaTiO₃ composite showed good chemical stability, which is beneficial for practical applications in air pollution removal.

光催化被认为是去除氮氧化物（NO）的有前途的技术，但是，可见光照射下的低光催化效率和光催化剂的失活仍然是应解决的重要问题。在这项工作中，可见光驱动的Bi ₂ Ti ₂ O ₇ / CaTiO ₃异质结复合材料是通过一种简便的原位水热法合成的。与纯CaTiO ₃和纯Bi ₂ Ti ₂ O ₇相比，Bi ₂ Ti ₂ O ₇ / CaTiO ₃复合材料显示出优异的可见光光催化活性。去除空气中600 ppb的NO。在所有复合材料中，包含20 wt％Bi ₂ Ti ₂ O _7的Bi ₂ Ti ₂ O ₇ / CaTiO ₃表现出最佳的光催化活性，最大去除效率为59％。改善的光催化性能主要归因于强大的可见光吸收能力，适当密度的氧空位缺陷的存在以及CaTiO ₃与Bi ₂ Ti ₂ O ₇之间形成异质结。，通过光致发光（PL）和光感应电流测量证明了界面处的有效电荷分离。据捕获实验和自旋捕获ESR分析，^• Ò ₂ ^-和H ⁺是参与光催化NO脱除的主要反应性物种。另外，所获得的Bi ₂ Ti ₂ O ₇ / CaTiO ₃复合材料显示出良好的化学稳定性，这对于去除空气污染中的实际应用是有利的。