Recent advances in covalent organic frameworks (COFs) as a smart sensing material are summarized and highlighted.

Semiconductor photocatalysis, a sustainable and renewable technology, is deemed to be a new path to resolve environmental pollution and energy shortage. The development of effective photocatalysts, especially the metal‐free photocatalysts, is a critical determinant of this technique. The recently emerged 2D material of black phosphorus with distinctive properties of tunable direct bandgap, ultrahigh charge mobility, fortified optical absorption, large specific surface area, and anisotropic structure has captured enormous attention since the first exfoliation of bulk black phosphorus into mono‐ or few layered phosphorene in 2014. In this article, the state‐of‐the‐art preparation methods are first summarized for bulk black phosphorus, phosphorene, and black phosphorus quantum dot and then the fundamental structure and electronic and optical properties are analyzed to evaluate its feasibility as a metal‐free photocatalyst. Various modifications on black phosphorus are also summarized to enhance its photocatalytic performance. Furthermore, the multifarious applications such as solar to energy conversion, organic removal, disinfection, nitrogen fixation, and photodynamic therapy are discussed and some of the future challenges and opportunities for black phosphorus research are proposed. This review reveals that the rising star of black phosphorus will be a multifunctional material in the postgraphene era.

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An efficient binary BiFeO/BiWO Z-scheme heterojunction was fabricated through a facile hydrothermal route. The obtained BiFeO/BiWO displays high catalytic activity for rhodamine B (RhB) photodegradation, and 100% of RhB was photodegraded by BiFeO (7%)/BiWO within 90 min, which is much better than that by pure BiFeO and BiWO. The effective photoinduced carrier separation, the broadened photoabsorption range, high oxidation capacity of hole, and the high reduction power of electron are in charge of the elevated catalytic activity because of the formed Z-scheme system. In addition, the effects such as pollutant concentration, pH, inorganic anions, and water sources exerted on photocatalytic performance were also investigated, and the results suggest that BiFeO/BiWO still possesses a high photocatalytic performance. The free-radical trapping experiments and electron spin resonance spin-trapping technology disclose that hole (h), hydroxy radical (OH), and superoxide radical (O) are cardinal active radicals in the catalytic system. In terms of the above experimental analysis, a possible photodegradation mechanism of the as-fabricated photocatalyst is thoroughly elucidated. In addition, the possible RhB photodegradation pathway is also raised in the light of the analysis of liquid chromatography-mass/mass spectrometry. In addition, BiFeO/BiWO composite does not display dramatic reduction of the catalytic performance after five recycles. Thus, this study reveals that the as-obtained BiFeO/BiWO catalyst has a great prospect for the environmental purification.

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