Potential utility of BiOX photocatalysts and their design/modification strategies for the optimum reduction of CO(2).

As an effective means to efficiently control the emissions of carbon dioxide (CO2), photo-conversion of CO2 into solar fuels (or their precursors) is meaningful both as an option to generate cleaner energy and to alleviate global warming. In this regard, bismuth oxyhalide (BiOX, where X = Cl, Br, and I) semiconductors have sparked considerable interest due to their multiple merits (e.g., visible light-harvesting, efficient charge carriers separation, and excellent chemical stability). In this review, the fundamental aspects of BiOX-based photocatalysts are discussed in relation to their modification strategies and associated reduction mechanisms of CO2 to help expand their applicabilities. In this context, their performance is also evaluated in terms of the key performance metrics (e.g., quantum efficiency (QE), space-time yield (STY), and figure of merit (FoM)). Accordingly, the morphology design of BiOX materials is turned out as one of the most efficient strategies for the maximum yield of CO while the introduction of heterojunctions into BiOX materials was more suitable for CH4 formation. As such, the adoption of the proper modification approach is recommended for efficient conversion of CO2.

Sun Y ，Younis SA ，Kim KH ，Kumar V ... -  《-》

Recent advances on bismuth oxyhalides for photocatalytic CO(2) reduction.

Photocatalytic conversion of CO2 into fuels such as CO, CH4, and CH3OH, is a promising approach for achieving carbon neutrality. Bismuth oxyhalides (BiOX, where X = Cl, Br, and I) are appropriate photocatalysts for this purpose due to the merits of visible-light-active, efficient charge separation, and easy-to-modify crystal structure and surface properties. For practical applications, multiple strategies have been proposed to develop high-efficiency BiOX-based photocatalysts. This review summarizes the development of different approaches to prepare BiOX-based photocatalysts for efficient CO2 reduction. In the review, the fundamentals of photocatalytic CO2 reduction are introduced. Then, several widely used modification methods for BiOX photocatalysts are systematacially discussed, including heterojunction construction, introducing oxygen vacancies (OVs), Bi-enrichment, heteroatom-doping, and morphology design. Finally, the challenges and prospects in the design of future BiOX-based photocatalysis for efficient CO2 reduction are examined.

Xu L ，Yu JC ，Wang Y 《Journal of Environmental Sciences》

BiOX (X = Cl, Br, I) photocatalytic nanomaterials: Applications for fuels and environmental management.

Energy and environmental issues are the major concerns in our contemporary "risk society". As a green technique, photocatalysis has been identified as a promising solution for above-mentioned problems. In recent decade, BiOX (X = Cl, Br, I) photocatalytic nanomaterials have sparked numerous interest as economical and efficient photocatalysts for energy conversion and environmental management. The distinctive physicochemical properties of BiOX nanomaterials, especially their energy band structures and levels as well as relaxed layered nanostructures, should be responsible for the visible-light-driven photocatalytic performance improvement, which could be utilized in dealing with the global energy and environmental challenges. In this review, recent advances for the enhancement of BiOX photocatalytic activity are detailedly summarized. Furthermore, the applications of BiOX photocatalysts in water splitting and refractory organic pollutants removal are highlighted to offer guidelines for better development in photocatalysis. Particularly, no relative reports in previous studies were documented in CO2 reduction as well as heavy metals and air pollutants removal, thus this review presented as a considerable research value. Challenges in the construction of high-performance BiOX-based photocatalytic systems are also discussed. With the exponential growth of studies on BiOX photocatalytic nanomaterials, this review provides unique and comprehensive perspectives to design BiOX-based photocatalytic systems with superior visible light photocatalytic activity. The knowledge of both the merits and demerits of BiOX photocatalysts are updated and provided as a reference.

Yang Y ，Zhang C ，Lai C ，Zeng G ，Huang D ，Cheng M ，Wang J ，Chen F ，Zhou C ，Xiong W ... -  《-》

Recent advances in bismuth oxyhalide photocatalysts for degradation of organic pollutants in wastewater.

Photocatalysis has been considered as an environmental-friendly strategy for degradation of organic pollutants to the nontoxic products of H2O and CO2. Compared to metal oxide semiconductors, BiOX (X = Cl, Br and I) photocatalysts exhibit some advantages, such as, unique layered structure, good chemical stability and superior photocatalytic activity. This review provides an overview on the controllable synthesis of BiOX-based photocatalysts and their application in photodegradation of organic pollutants. Firstly, the controllable synthesis of BiOX is introduced, including hydrothermal, solvothermal, hydrolysis, precipitation, two-phase methods, ultrasonic/microwave-assisted methods, and physical methods. Then, the doping and surface modification of BiOX are summarized, including non-metal doping, metal doping, dual doping, and the modification by introducing surface terminations or carriers. In addition, the heterojunctions of BiOX/BiOY and BiOX/Bi m O n X z are introduced. At last, the promising research trends of BiOX-based photocatalysts are put forward. The main purpose is providing practical guidelines for developing high-performance BiOX photocatalysts.

Li Y ，Jiang H ，Wang X ，Hong X ，Liang B ... -  《-》

Bismuth-Based Photocatalysts for Solar Photocatalytic Carbon Dioxide Conversion.

Photocatalytic CO2 conversion into solar fuels is an effective means for simultaneously solving both the greenhouse effect and energy crisis. In the past ten years, bismuth-based photocatalysts for environmental remediation have experienced a golden period of development. However, solar photocatalytic CO2 conversion has only been developed over the past five years and, until now, no reviews have been published on bismuth-based photocatalysts for the photocatalytic conversion of CO2 . For the first time, solar photocatalytic CO2 conversion systems are reviewed herein. Synthetic methods and photocatalytic CO2 performances of bismuth-based photocatalysts, including Sillén-structured BiOX (X=Cl, Br, I); Aurivillius-structured Bi2 MO6 (M=Mo, W); and Scheelite-structured BiVO4 , Bi2 S3 , BiYO3 , and BiOIO3 , are summarized. In addition, activity-enhancing strategies for this photocatalyst family, including oxygen vacancies, bismuth-rich strategy, facet control, conventional type II heterojunction, Z-scheme heterojunction, and cocatalyst deposition, are reviewed. Finally, the main mechanistic research methods, such as in situ FTIR spectroscopy and theoretical calculations, are presented. Challenges and research trends reported in studies of bismuth-based photocatalysts for photocatalytic CO2 conversion are discussed and summarized.

Ye L ，Deng Y ，Wang L ，Xie H ，Su F ... -  《-》