Selective catalytic reduction (SCR) stands out as a pivotal method for curbing NO_x emissions from flue gas. The support, crucially, for SCR efficacy, loads and interacts with the active components within the catalyst. The catalysts could be amplified by the denitration performance of the catalyst by enhancements in support pore structure, acidity, and mechanical robustness. These improvements ensure efficient interaction between the support and active materials, thereby optimizing the structure and property of the catalysts. TiO₂ is the most commonly used support of the NH₃-SCR catalyst. The catalyst with TiO₂ support has poor thermal stability and a narrow temperature range, which can be improved. This paper reviews the research progress on the effects of various aspects of TiO₂ support on the NH₃-SCR catalyst’s performance, focusing on the TiO₂ crystal type, TiO₂ crystal surface, different TiO₂ structures, TiO₂ support preparation methods, and the effects of TiO₂-X composite support on the NH₃-SCR catalyst’s performance. The reaction mechanism, denitrification performance, and anti-SO₂/H₂O poisoning performance and mechanism of TiO₂ support with different characteristics were described. At the same time, the development trend of the NH₃-SCR catalyst using TiO₂ as the support is prospected. It is hoped that this work can provide optimization ideas for SCR catalyst research.

Increasing the concentration of oxygen vacancies in ceria-based materials to solve the bottleneck of their applications in various fields has always been a research hotspot. In this paper, ceria-based cerium–oxygen–sulfur (Ce-O-S) composites that were composed of CeO₂, Ce₄O₄S₃, and Ce₂(SO₄)₃ were synthesized by a precipitation method. The compositional, structural, morphological, and light response characteristics of prepared Ce-O-S composites were investigated by various characterization techniques. The molar ratio of oxygen vacancies to lattice oxygen can reach a maximum of 1.83 with Ce-O-S composites. The band gap values of the Ce-O-S composites were less than 3.00 eV, and the minimum value was 2.89 eV (at pH 12), which successfully extended the light response range from the ultraviolet light region to the short-wave blue light region. The remarkable light response performance of Ce-O-S composites can be mainly attributed to the high proportion of oxygen vacancy. Moreover, the higher proportion of oxygen vacancies can be attributed to the doping of Ce (+3) and S (−2) in the lattice of CeO₂, and the synergistic effect of CeO₂, Ce₄O₄S₃, and Ce₂(SO₄)₃. Moreover, the ceria-based Ce-O-S composites with rich oxygen vacancy in this research can be applied in light blocking, photocatalysis, and other related fields.