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In this study, the elastocaloric and magnetocaloric effects in a paramagnetic shape memory alloy, i.e., Co37.5Ni34.5Al28alloy were investigated. The study reveals that the alloy shows an elastocaloric effect with a temperature change of 2.2 K under 400 Mpa keeping a strain rate of 0.25 s−1. It shows a temperature change of over 1 K within a temperature span of 50 K including the room temperature. Under the same stress, with a strain rate of 0.50 s−1, the material shows a temperature change of 2.7 K and gives more than 1 K temperature change within a span of 75 K including the ambient temperature. However, increasing the strain rate to 0.62 s−1causes the material to break down. This shows that under a certain limit, the increase in the strain rate increases the elastocaloric temperature change and enhances the temperature window of the material along with the peak shifts toward lower measuring temperatures. Moreover, the study deduces that the material also exhibits a magnetocaloric effect. The study also reveals that both of the effects show temperature changes with the same sign and in the same region of the working temperature, thus enhancing one another.

Advanced adsorbents need high adsorption rate and superior adsorption capability to clean up organic methylene blue (MB) from wastewater. We prepared K2Ti8O17nanowires grown along the [0 1 0] direction with a one-step hydrothermal method. The K2Ti8O17nanowires with tens of nanometers in diameter and tens of micrometers in length were achieved with smooth surfaces and twisted wire-like morphology. The K2Ti8O17nanowires exhibit high uptake capacity of ∼208.8 mg·g–1in the MB removal under equilibrium pH = 7. The adsorption equilibrium of MB onto the K2Ti8O17adsorbent is achieved with a 97% removal rate of MB within only ∼21 min, which is the shortest adsorption time among the recently reported inorganic adsorbents toward MB. The adsorption process has a good agreement with the well-known pseudo-second-order kinetic model (k2= 0.2) and the Langmuir isotherm model. Fourier transform infrared measurements suggest that the adsorption can be assigned to the hydrogen bonding and electrostatic attraction between MB and K2Ti8O17. This ultrafast removal ability is due to the larger (0 2 0) interplanar spacing and zigzag surface structure of the nanowires, which provide abundant active adsorption sites. Thermodynamic parameters reflect the spontaneous, exothermic, and feasible uptake of MB. Besides, K2Ti8O17nanowires enjoy high adsorptive ability for chromium(VI) ions and photocatalytic removal toward NO. This work highlights the great significance of K2Ti8O17nanowires as a low-cost promising material used for the adsorptive elimination of organic contaminations in fast water purification on a large scale.

Doping and novel metallic nanoparticles loading on the photocatalyst are two effective means to enhance its photocatalytic activity. In our study, Pd0/Pd2+-co-modified ZnWO4nanorods were fabricated by a two-step hydrothermal process and room-temperature reduction method. The performance of the as-prepared samples was evaluated through the photocatalytic nitric oxide (NOx) removal under simulated solar and visible-light irradiation. Pd0/Pd2+-co-modified ZnWO4nanorods present a significantly enhanced photocatalytic activity for NOxremoval compared with Pd0-loaded or Pd2+-doped ZnWO4under simulated sunlight irradiation owing to a narrower band gap of Pd2+doping compared with that of pure ZnWO4. The role of Pd0nanoparticles is to act as an electron reservoir to restrain the recombination of e–/h+pairs. According to the trapping measurements, the photoinduced holes and electrons play critical roles during the photocatalytic process. In addition, electron spin resonance (ESR) results further confirm that •O2–and •OH radicals are present and assist in the photocatalysis under simulated solar light irradiation. Stability test demonstrated that 1.5% Pd0/0.5% Pd2+-co-modified ZnWO4nanorods as photocatalyst have high photocatalytic stability in NOxremoval. This work proved that Pd0/Pd2+-co-modified ZnWO4nanorods can be considered as an efficient photocatalyst for NOxremoval.

Novel multifeatured hollandite K1.46Fe0.8Ti7.2O16(KFTO) was synthesized by a simple hydrothermal method. Magnetic KFTO microrods were well controlled to long rectangular rods with pyramid-shaped tops. A KFTO growth mechanism was proposed on the basis of examining phase and morphology of the samples acquired at different reaction times. The KFTO morphology was confirmed by the calculated surface energies. The UV–vis diffuse reflectance spectra of KFTO microrods showed double absorption with band gaps of 2.01 and 2.16 eV, which was further confirmed by photoluminescence. First-principles studies revealed that the double absorption and magnetic properties originate from the d–d transitions of Fe3+under the crystal field. The magnetic property could be applied in ferromagnetic semiconductor devices and the double absorption could be applied in visible-light harvesting. This work highlights the multifunctional KFTO microrods with low cost and environmental friendliness.