A comprehensive review on oxygen vacancy modified photocatalysts including synthesis (controllability of location, content, etc. ), characterization (qualitative, quantitative and locational analysis), and applications and mechanisms.

In the context of the global energy structure transformation, concentrated solar power (CSP) technology has gained significant attention. Its future trajectory is oriented towards the construction of ultra-high temperature (700–1000 °C) power plants, aiming to enhance thermoelectric conversion efficiency and economic competitiveness. Chloride molten salts, serving as a crucial heat transfer and storage medium in the third-generation CSP system, offer numerous advantages. However, they are highly corrosive to metal materials. This paper provides a comprehensive review of the corrosion behaviors of stainless steels and high-temperature alloys in molten salts. It analyzes the impacts of factors such as temperature and oxygen, and it summarizes various corrosion types, including intergranular corrosion and hot corrosion, along with their underlying mechanisms. Simultaneously, it presents an overview of the types, characteristics, impurity effects, and purification methods of molten salts used for high-temperature heat storage and heat transfer. Moreover, it explores novel technologies such as alternative molten salts, solid particles, gases, liquid metals, and the carbon dioxide Brayton cycle, as well as research directions for improving material performance, like the application of nanoparticles and surface coatings. At present, the corrosion of metal materials in high-temperature molten salts poses a significant bottleneck in the development of CSP. Future research should prioritize the development of commercial alloy materials resistant to chloride molten salt corrosion and conduct in-depth investigations into related influencing factors. This will provide essential support for the advancement of CSP technology.

The piezoelectric enhancement of photo‐catalytic activity for water splitting and pollutant degradation is a novel approach to developing renewable energy and environmental protection applications. Herein, a new form of defect engineered Na‐Sm bimetallic‐regulated CaBi₂Nb₂O₉ platelet is synthesized via a molten salt process for water splitting and pollutant degradation applications. An intermediate band structure is introduced by Sm‐doping, and empty orbitals in the conductive band are introduced by Na‐doping. These factors, combined with the increased local charge density around the Sm and Na atoms, result in an increased electrical conductivity, improved electron mobility, and provide additional electrons for enhancing catalytic reactions. As a consequence, the judicious co‐doping of CaBi₂Nb₂O₉ with Sm and Na leads to a unique synergetic piezo‐photo‐electric effect to provide a superior piezo‐photo‐catalytic performance for H₂ production (158.53 µmol g⁻¹ h⁻¹) and pollutant degradation (rate constant, k = 0.257 min⁻¹). This new approach provides important insights into the application of defect engineering to exploit the cooperative doping of alkaline earth metals and rare metals to create high‐performance catalysts.