Tannin/cellulose microspheres (T/C) were successfully prepared via a facile homogeneous reaction in a water/oil (W/O) emulsion for removing Pb(II) ions from aqueous solution. The structure of the microspheres was characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, and a zeta potential test. The effects of pH, adsorbent dosage, contact time, and temperature on adsorption ability were investigated. The results showed that T/C microspheres could combine Pb(II)ions via electrostatic attractions and physical adsorption. Adsorption kinetics could be better described by the pseudo-second-order kinetic model. The adsorption behaviors were in agreement with the Langmuir adsorption isotherm model with a fitting correlation coefficient of 0.9992. The maximum adsorption capacity was 23.75 mg/g from the Langmuir isotherm evaluation at 308K with an initial pH of 5. The results suggested that tannin/cellulose microspheres could be a low-cost and effective adsorbent for removing Pb(II) ions from aqueous solution.

A catalyst determines the mechanism of an organic chemical reaction, thus enabling the commercially viable formation of desired material products. Biopolymers offer new opportunities for the construction of catalysts by virtue of their biocompatibility, environmental benignity, and sustainability, as well as their low cost. Biopolymers are especially useful as carriers and precursors in catalysis application. The employment of biocompatible and biosustainable collagen and silk fibroin materials will revolutionize state-of-the-art electronic devices and systems that currently rely on conventional technologies. In this review, we first consider the ordered hierarchical structure, origin, and processing methods of collagen and silk fibroin. Then, the unique advantages and applicability of collagen and silk fibroin for constructing catalysts are summarized. Moreover, a summary of the state-of-the-art design, fabrication, and application of collagen- and silk fibroin-based catalysts, as well as the application of collagen- and silk-based catalysts, is presented by focusing on their roles as carriers and precursors, respectively. Finally, challenges and prospects are assessed for the construction and development of collagen and silk fibroin-based catalysts.

Van der Waals heterostructures have also been demonstrated to exhibit remarkable performance in optoelectronic devices. Here, a self-driven photodetector based on GaSe/MoSe2 field-effect transistor (FET) was designed and fabricated. The built-in electric field in the type-II band alignment can exhibit excellent response and serve as an equivalent of a bias voltage. Moreover, the detector can achieve a broad bandwidth spanning from 520 nm to 850 nm, with peak responsivity observed at 785 nm. The heterostructure device produced responsivity of 0.47 A/W at a power density of 80 mW/cm2, an external quantum efficiency of 74.4%, a specific detectivity of 9.65×109 Jones, and a fast photoresponse speed (24.6 ms). In addition, the photodetector presents a well-defined rectification ratio of 95.6, which is comparable to that of a conventional diode. These results indicate that GaSe/MoSe2 photodetectors can provide high performance for future optoelectronic devices.