Abstract Heavy metal pollution has become increasingly serious in recent decades with the progress of industrialization, posing a significant threat to human health. This raises the demand for portable and ease of use heavy metal ion detection devices. In this study, we develop ultra-thin (5 µ m) and highly flexible composite paper of MXene/bacterial cellulose (M/BC x , with x denoting the BC content) and apply it in a self-powered triboelectric nanosensor (TENS) to do heavy metal ion detection. The M/BC x composite paper is fabricated using a simple vacuum filtration method, and combines the advantages of the high electrical conductivity of MXene with the excellent mechanical properties of BC. The TENS employs the M/BC x composite paper and polytetrafluoroethylene as the friction layers, and the influences of different ratios of M/BC x on the electrical signals is investigated. The TENS shows high sensitivity in the detection of Cu 2+ , Cr 3+ , and Zn 2+ , as the detection limit is as low as 1 µ M without the need of ligand molecules. A linear range of 10–300 µ M is obtained. The TENS also shows excellent stability after more than 10 000 continuous operations. This simple-structured, cost-effective and durable TENS device provides new insights into the methodology of heavy metal ion detection and can be further developed for the detection of the corresponding ions in serum.
Abstract Heavy metal pollution has become increasingly serious in recent decades with the progress of industrialization, posing a significant threat to human health. This raises the demand for portable and ease of use heavy metal ion detection devices. In this study, we develop ultra-thin (5µm) and highly flexible composite paper of MXene/bacterial cellulose (M/BCx, with x denoting the BC content) and apply it in a self-powered triboelectric nanosensor (TENS) to do heavy metal ion detection. The M/BCx composite paper is fabricated using a simple vacuum filtration method, and combines the advantages of the high electrical conductivity of MXene with the excellent mechanical properties of BC. The TENS employs the M/BCx composite paper and PTFE as the friction layers, and the influences of different ratios of M/BCx on the electrical signals is investigated. The TENS shows high sensitivity in the detection of Cu2+, Cr3+, and Zn2+, as the detection limit is as low as 1µM without the need of ligand molecules. A linear range of 10 µM to 300 µM is obtained. The TENS also shows excellent stability after more than 10,000 continuous operations. This simple-structured, cost-effective and durable TENS device provides new insights into the methodology of heavy metal ion detection and can be further developed for the detection of the corresponding ions in serum.
In 2013 Raytheon began to integrate deep submicron (≤0.25 µm gate) 200mm GaN on Si HEMT processes within a commercial CMOS Si Foundry environment. When fully realized, these processes will demonstrate multi GHz GaN on Si MMICs by leveraging a fully subtractively processed transistor coupled with multi level copper based back end of line (Cu BEOL) processes. This work provides a status update on the progress towards that goal.
Typically, transition metals are considered as the centers for the activation of dinitrogen. Here we demonstrate that the nitride hydride compound Ca3 CrN3 H, with robust ammonia synthesis activity, can activate dinitrogen through active sites where calcium provides the primary coordination environment. DFT calculations also reveal that an associative mechanism is favorable, distinct from the dissociative mechanism found in traditional Ru or Fe catalysts. This work shows the potential of alkaline earth metal hydride catalysts and other related 1 D hydride/electrides for ammonia synthesis.
Human-machine interfaces have penetrated various academia and industry fields such as smartphones, robotic, virtual reality, and wearable electronics, due to their abundant functional sensors and information interaction methods. Nevertheless, most sensors' complex structural design, monotonous parameter detection capability, and single information coding communication hinder their rapid development. As the frontier of self-powered sensors, the triboelectric nanogenerator (TENG) has multiple working modes and high structural adaptability, which is a potential solution for multi-parameter sensing and miniaturizing of traditional interactive electronic devices. Herein, a self-powered hybrid coder (SHC) based on TENG is reported to encode two action parameters of touch and press, which can be used as a smart interface for human-machine interaction. The top-down hollow structure of the SHC, not only constructs a compositing mode to generate stable touch and press signals but also builds a hybrid coding platform for generating action codes in synergy mode. When a finger touches or presses the SHC, Morse code and Gray code can be transmitted for text information or remote control of electric devices. This self-powered coder is of reference value for designing an alternative human-machine interface and having the potential to contribute to the next generation of highly integrated portable smart electronics.
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