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The development of high‐performance anode materials for potassium‐based energy storage devices with long‐term cyclability requires combined innovations from rational material design to electrolyte optimization. A three‐dimensional K+‐pre‐intercalated Ti3C2Tx MXene with enlarged interlayer distance was constructed for efficient electrochemical potassium‐ion storage. We found that the optimized solvation structure of the concentrated ether‐based electrolyte leads to the formation of a thin and inorganic‐rich solid electrolyte interphase (SEI) on the K+‐pre‐intercalated Ti3C2Tx electrode, which is beneficial for interfacial stability and reaction kinetics. As a proof of concept, 3D K+‐Ti3C2Tx//activated carbon (AC) potassium‐ion hybrid capacitors (PIHCs) were assembled, which exhibited promising electrochemical performances. These results highlight the significant roles of both rational structure design and electrolyte optimization for highly reactive MXene‐based anode materials in energy storage devices. [ABSTRACT FROM AUTHOR]

Developing novel catalysts with both easily accessible recyclability and long-term durability toward chemical synthesis is highly desirable yet remains to be explored. In this work, a porous and bulk sponge-confined bismuth (Bi)/Ti3C2Tx (MXene) composite as a monolithic catalyst is synthesized via the photodeposition of Bi nanoparticles with a mean size of 4.4 nm on Ti3C2Tx followed by electrostatic self-assembly between the negatively charged Bi/Ti3C2Tx and positively charged sponge. It is noteworthy that compared to the analogue of widely investigated reduced graphene oxide, Ti3C2Tx with favorable hydrophilic surface groups as the scaffold for the high dispersion of Bi nanoparticles benefits not only efficient aqueous phase catalytic reactions, but also strong electrostatic interaction with the sponge substrate for ensuring the recyclability towards practical applications. As a result, the bulk sponge-confined Bi/Ti3C2Tx as an easily recyclable catalyst possesses both improved catalytic performance and long-term durability for the hydrogenation of nitroarenes in the aqueous phase. This study presents a facile and valuable protocol for functionalizing inexpensively available porous bulk materials to confine catalysts towards integrated materials featuring easy-separation and long-term stability for practical catalytic processes. [ABSTRACT FROM AUTHOR]

Constructing heterostructured photocatalysts with highly exposed active sites proves to be an efficient strategy to improve the photocatalytic performance of bismuth-based photocatalysts. In this work, active site-exposed Bi 2 WO 6 @BiOCl (BWO@BOC) heterostructure composites based on two bismuth-based materials were fabricated by an in situ growth method for improving the photocatalytic hydrogenation of 4-aniline (4-NA) to p -phenylenediamine (PPD). BWO@BOC exhibited enhanced photoactivity for 4-NA hydrogenation compared to pure BWO and BOC. The optimal BWO@BOC composites displayed the highest conversion rate of 4-NA to PPD up to 99.3% within 12 min, with an apparent reaction rate constant of 0.414 min -1 , which is 3.3 times that of pure BOC. The photoactivity enhancement is mainly ascribed to the construction of a tight Z-scheme heterostructure with improved light harvesting properties and charge carrier transport efficiency, which were revealed by optical and photoelectrochemical characterization, respectively. Furthermore, the products of the hydrogenation process were monitored by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to gain a better insight into the 4-NA hydrogenation mechanism.

Engineering the spatial separation and transfer of photogenerated charge carriers has been one of the most enduring research topics in the field of photocatalysis due to its crucial role in determining the performances of photocatalysts. Herein, as a proof-of-concept, Ti 3 C 2 T x MXene is coupled with a typical heterojunction of TiO 2 @CdS through a co-assembly strategy to boost electron pumping towards improving the photocatalytic efficiency. In addition to the band alignment-mediated electron transfer in TiO 2 @CdS-Ti 3 C 2 T x heterojunctions, the plasmon-induced electric field enhancement of Ti 3 C 2 T x is found to cooperate with the electron-reservoir role of Ti 3 C 2 T x to extract photoinduced electrons. The synergistic dual functions of Ti 3 C 2 T x promote multichannel electron transfer in TiO 2 @CdS-Ti 3 C 2 T x hybrids to improve the photocatalytic efficiency. These results intuitively show that there is a wide scope to manipulate the spatial separation and transfer of photoinduced electrons by cultivating the fertile ground of Ti 3 C 2 T x toward boosting the efficiency of solar-to-chemical conversion.

The development of high-performance anode materials for potassium-based energy storage devices with long-term cyclability requires combined innovations from rational material design to electrolyte optimization. A three-dimensional K + -pre-intercalated Ti 3 C 2 T x MXene with enlarged interlayer distance was constructed for efficient electrochemical potassium-ion storage. We found that the optimized solvation structure of the concentrated ether-based electrolyte leads to the formation of a thin and inorganic-rich solid electrolyte interphase (SEI) on the K + -pre-intercalated Ti 3 C 2 T x electrode, which is beneficial for interfacial stability and reaction kinetics. As a proof of concept, 3D K + -Ti 3 C 2 T x //activated carbon (AC) potassium-ion hybrid capacitors (PIHCs) were assembled, which exhibited promising electrochemical performances. These results highlight the significant roles of both rational structure design and electrolyte optimization for highly reactive MXene-based anode materials in energy storage devices., (© 2021 Wiley-VCH GmbH.)

The homemade explosive, triacetone triperoxide (TATP), is easy to synthesize, sensitive to detonation but hard to detect directly. Vapor sensor arrays composed of a few sensor materials have the potential to discriminate TATP, but the stability of the sensor array is always a tricky problem since each sensor may encounter a device fault. Thus, a sensor array based on a single optoelectronic TiO₂/PW 11 sensor was first constructed by regulating the excitation wavelength to discriminate TATP from other explosives. By in situ doping of Na₃PW 12 O 40 , a Keggin structure of PW 11 formed on the TiO₂ to promote the photoinduced electron-hole separation, thus obviously improving the detection sensitivity of the sensor film and shortening the response time. The response of the TiO₂/PW 11 sensor film to TATP under 365, 450 and 550 nm illumination is 81%, 42%, and 37%, respectively. The TiO₂/PW 11 sensor features selectivity to TATP and is able to detect less than 50 ppb. The flexibility and stability of the flexible sensor film is also demonstrated with the extent of bending. Furthermore, the sensing response cannot be affected by ambient air below 60% relative humidity., Competing Interests: The authors declare no conflicts of interest.