Flexible pressure sensors usually exhibit high sensitivity, excellent resolution, and can be mass-produced. Herein, a high-resolution, capacitive, paper-based, 3D-printed pressure sensor with a simple, low-cost preparation method is proposed. The sensor has a wide detection range (300–44,000 Pa), a short response time (<50 ms), and high mechanical stability during repeated loading/unloading (3750 Pa). It can measure the weight of an object precisely, from which the shape of the object can be predicted. The sensor can also perform gait detection. The advantages presented by low-cost, high sensitivity, wide detection range, and the ability to be mass-produced make these sensors potential candidates for applications in contact detection and wearable medical devices.

High activity and recycling efficient are exciting characteristics of photocatalysts for water treatment. In this contribution, we report the synthesis methods and photocatalytic properties of Fe₃O₄-SiO₂-TiO₂ core-shell nanoparticles (FST NPs). The magnetic Fe₃O₄, which is synthesized via carbon reduction, is used as core, and the SiO₂ intermitted layer and TiO₂ outside layer are prepared by sol-gel method. The hierarchic structure and the components of the FST NPs were demonstrated by transmission electron microscope and X-ray diffraction. The optimum ratio of alcohol, ester, and water was determined as 4.6:12.3:1 and 30.3:12.5:1 for the SiO₂ and TiO₂ layers, respectively. The X-ray photoelectron spectroscopy, magnetism, and photocatalytic activity of the FST NPs were tested as well. It is found that the methyl orange solution at a concentration of 10 mg/L can be decomposed completely within 240 min by the FST NPs.