Vacancy defect engineering in semiconductors for solar light‐driven environmental remediation and sustainable energy production

Abstract

The introduction of vacancy defects in semiconductors has been proven to be a highly effective approach to improve their photocatalytic activity owing to their advantages of promoting light absorption, facilitating photogenerated carrier separation, optimizing electronic structure, and enabling the production of reactive radicals. Herein, we outline the state-of-the-art vacancy-engineered photocatalysts in various applications and reveal how the vacancies influence photocatalytic performance. Specifically, the types of vacancy defects, the methods for tailoring vacancies, the advanced characterization techniques, the categories of photocatalysts with vacancy defects, and the corresponding photocatalytic behaviors are presented. Meanwhile, the methods of vacancies creation and the related photocatalytic performance are correlated, which can be very useful to guide the readers to quickly obtain indepth knowledge and to have a good idea about the selection of defect engineering methods. The precise characterization of vacancy defects is highly challenging. This review describes the accurate use of a series of characterization techniques with detailed comments and suggestions. This represents the uniqueness of this comprehensive review. The challenges and development prospects in engineering photocatalysts with vacancy defects for practical applications are discussed to provide a promising research direction in this field.

Emerging heterostructured C3N4photocatalysts for photocatalytic environmental pollutant elimination and sterilization

“…Up to now, a variety of modification methods such as ion doping, defect introduction, heterostructure construction, surface modification, and noble metal nanoparticle decoration have been developed for improving photocatalytic reaction rates. [31][32][33][34][35] In particular, the combination of g-C 3 N 4 with other semiconductors to obtain heterostructures has proven the most effective. Usually, engineering heterojunctions can effectively increase the visible light response range and promote photoinduced charge dissociation of photocatalysts.…”

Bioinspired Strategy for Efficient TiO2/Au/CdS Photocatalysts Based On Mesocrystal Superstructures in Biominerals and Charge-Transfer Pathway in Natural Photosynthesis

“…The direct conversion of solar energy to highly active chemical energy through photocatalytic water splitting has been considered as an attractive approach to tackle current energy shortages and environmental crisis problems. − However, serious recombination of photogenerated electron–hole pairs leads to a low-energy conversion efficiency in most artificial systems. − Natural photosynthesis, regarded as an important bioprocess, has a subtle electron-transfer mechanism in which photogenerated electron–hole pairs are rapidly separated by multiple electron-transfer intermediates between photosystem II and photosystem I, thus providing almost 100% quantum efficiency. , Inspired by this unique photogenerated-carrier transportation path, recent studies have focused on designing artificial photosynthesis systems. For instance, the approach of immense interest is utilizing semiconductors and noble metals to, respectively, emulate photosystems and electron-transfer intermediates for introducing efficient charge separation chains in artificial photosynthesis systems. ,, This well-designed charge-transfer pathway confers long-lived photogenerated carriers for subsequent redox processes, but the lack of focus on the rational design principle of the structure of semiconductors is still an obstacle for pursuing improved performance.…”

Red Emissive Upconversion Carbon Quantum Dots Modifying TiO2 for Enhanced Photocatalytic Performance

“…As a result, TiO 2 is used in a variety of fields, including water splitting, air purification, wastewater treatment, and solar cell production. 10 However, TiO 2 has relatively poor performance due to a number of limiting variables, which is the main barrier to obtain efficient photocatalysis. 11,12 The main factors include rapid recombination of photogenerated charge carriers, low charge separation at the interface, and poor light-harvesting efficiency because of their wide band gap (3.2, 3.02, and 2.96 eV) for the anatase, rutile, and brookite phases, respectively.…”

“…TiO 2 is regarded as a highly important photocatalyst among semiconductors due to its excellent properties, which include, but are not limited to, its low cost; significant photocatalytic efficiency; chemical durability; unique optical, structural, and electrical properties; and nontoxicity. As a result, TiO 2 is used in a variety of fields, including water splitting, air purification, wastewater treatment, and solar cell production . However, TiO 2 has relatively poor performance due to a number of limiting variables, which is the main barrier to obtain efficient photocatalysis. , The main factors include rapid recombination of photogenerated charge carriers, low charge separation at the interface, and poor light-harvesting efficiency because of their wide band gap (3.2, 3.02, and 2.96 eV) for the anatase, rutile, and brookite phases, respectively .…”