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Ravuri Hema Krishna,
- Professor, Department of Chemistry, Amrita Sai Institute of Science and Technology, Amrita Sai Nagar, Gani Atkuru Rd, Bathinapadu, Kanchikacherla Mandal, N.T.R, Andhra Pradesh, India
Abstract
Semiconductor photocatalysis has emerged as one of the most promising green technologies for addressing environmental pollution and global energy challenges through solar energy utilization. Nevertheless, the practical application of conventional semiconductor photocatalysts is often limited by their narrow visible-light absorption, rapid recombination of photogenerated electron–hole pairs, insufficient active sites, and poor charge-transfer efficiency. Defect engineering has recently attracted significant attention as an effective strategy to overcome these limitations by deliberately introducing structural imperfections into semiconductor materials. These defects, including oxygen vacancies, sulphur vacancies, nitrogen vacancies, metal vacancies, interstitial defects, antisite defects, grain boundaries, and dislocations, profoundly modify the electronic structure, surface chemistry, and catalytic properties of photocatalysts. Properly engineered defects create localized energy states within the bandgap, enhance visible-light absorption, facilitate efficient charge separation, improve carrier mobility, and provide abundant catalytic active sites, thereby significantly enhancing photocatalytic performance. Various synthesis approaches such as thermal reduction, plasma treatment, ion implantation, chemical etching, hydrothermal synthesis, solvothermal processing, hydrogenation, and laser irradiation have been developed to precisely regulate defect concentration and distribution. Advanced characterization techniques, including electron paramagnetic resonance spectroscopy-ray photoelectron spectroscopy, photoluminescence spectroscopy, Raman spectroscopy, transmission electron microscopy, scanning electron microscopy, and X-ray diffraction, are extensively employed to investigate defect structures and their influence on photocatalytic behaviour. This review comprehensively discusses the principles of semiconductor photocatalysis, defect engineering strategies, defect characterization methods, and the role of defects in enhancing photocatalytic activity. Furthermore, recent advances in defect-engineered photocatalysts, including titanium dioxide, zinc oxide, graphitic carbon nitride, bismuth vanadate, tungsten trioxide, cadmium sulphide, and other emerging semiconductor systems, are summarized. Finally, current challenges, future research directions, and opportunities for designing next-generation high-performance photocatalysts for environmental remediation and sustainable solar energy conversion are critically discussed.
Keywords: Semiconductor photocatalysis; Defect engineering; Oxygen vacancies; Crystal defects; Charge separation; Visible-light photocatalysis; Surface defects; Bandgap engineering; Environmental remediation; Solar energy conversion; Nanomaterials; Photocatalytic degradation.
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| Volume | 04 | |
| 02 | ||
| Received | 08/07/2026 | |
| Accepted | 28/07/2026 | |
| Published | 11/08/2026 | |
| Publication Time | 34 Days |