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Flexible electronics are excepted to be an important support for the next electronic age, and their quick, cost-effective, and easily realized fabrication is a key motivating factor to the on-going and future applications. The fabrication technique derived from day-to-day handwriting has prompted the advancement of producing flexible electronics with readily available, low-cost and user-friendly tools. Combined advances in materials science, mechanical engineering, and electrical engineering strengthen this method in implementing electronic components, circuits, sensors, and energy devices. This review focuses on the milestones and recent achievements of handwriting flexible electronics, concerning the available tools, writing mechanisms, involved materials, and emerging applications. On account of the merits and demerits of the handwriting technique, discussions and conclusions about the superiorities, possible usages, challenges and predictions are also presented.

Wearable sensors are attracting great attentions due to their potential applications in human health monitoring and caring systems. The wide utilization of wearable electronics may cause great burden to the environment, due to the vast contaminants generated in their fabrication and after their usage. Consequently, great efforts are devoted to the eco-friendly strategies for the material and fabrication in wearable sensors. Herein, recent advantages in developing wearable sensors with eco-friendly materials and green manufacturing approaches are reviewed. The functional materials with accessibility, recoverability and degradability have participated in the sensors as substrates, sensing elements and conductors. The fabrication strategies, from facile manual schemes to low-emission automated techniques are also introduced with their merits and demerits. Finally, the existing challenges and future opportunities in this field are summarized.

The utilization of CO2 to synthesize environmentally benign liquid fuels offers a solution to replacing depleting petroleum resources. Herein, a ternary CuZnZr (CZZ) metal oxide catalyst and a SAPO-34 zeolite were synthesized by co-precipitation and hydrothermal synthesis, respectively. Different metals were impregnated into the latter to obtain MeSAPO-34 (Me = Mn, Zn and Zr). A granule mixture of CZZ and MeSAPO-34 components (CZZ/MeSAPO-34 catalyst) was then effectively utilized in a tandem catalytic process for one-step CO2 hydrogenation to liquefied petroleum gas (LPG). The CZZ/MeSAPO-34 catalysts were characterized by using XRD, H2-TPR, BET, SEM-EDS and NH3-TPD techniques. SEM-EDS and XRD results indicated that an appropriate amount of Zr metal loading induced minimum zeolite framework collapse compared to a similar amount of Mn and Zn, which was more favorable for higher activity. In addition, NH3-TPD results revealed that the acidity of SAPO-34 could be altered after impregnation with different metals in different quantities. Tuning the acid density and strength, together with adjusting the CZZ to MeSAPO-34 weight ratio, had a collectively critical effect on LPG selectivity. An effective hydrogenation microenvironment which favors lower alkane formation (C3–C4) was enhanced after the acidity of the molecular sieve was tuned. LPG selectivity could reach 86% over the CZZ/5% ZrSAPO-34 catalyst at 2 MPa, 350 °C, a W/F ratio of 6, a H2/CO2 ratio of 3 and a weight ratio of 1.

This Note proposed a multi-direction piezoelectric energy harvester with a wide bandwidth and low working frequency, which is distinguished by the multiple working modes of the U-shaped beam and the high capacity of the pendulum in collecting arbitrary vibrations. The structural features are evaluated by finite element simulation and verified by experiments. At least three voltage peaks are generated in the frequency range of 0 Hz-25 Hz, and favorable harvesting consistency in different directions is achieved. The designed structure is adaptable in collecting energy from arbitrary vibration in ambient environments.