Ultrasensitive, Sustainable, and Selective Electrochemical Hydrazine Detection by ALD-Developed Two-Dimensional WO3

A redox-active covalent organic framework for the efficient detection and removal of hydrazine

The removal and detection of soluble hydrazine is of importance due to its harm to soil and subterranean water, but challenging. Herein, we preferentially disposed a porous and redox active covalent-organic framework (DAAQ-TFP COF, denoted as DQ-COF) to simultaneously removal and detect hydrazine. Electroactive sites (anthraquinone units) can be intelligently incorporated into the channel walls/pores of COF. DQ-COF has high crystallinity and good thermal stability, and DQ-COF dropped onto nickel matrix (DQ-COF/Ni composite) still retains high surface area, characterized by PXRD, FT-IR, nitrogen adsorption and TGA. Subsequently, a detailed study of DQ-COF towards hydrazine uptake and detection potentials is explored. DQ-COF as adsorbent unfolds strong removal ability towards hydrazine, the maximum removal capacity of which is up to 1108 mg g^-1, following Friedrich and pseudo-second-order kinetic models. Meanwhile, the DQ-COF supported on nickel renders attractive electrochemical properties, which is efficiently responsive to hydrazine at a part per billion (ppb) level, coupled with a wide linear range (0.5 ˜ 1223 μM), low detection limit (0.07 μM) and high anti-interference ability. There is no other COFs with such a favorable capability in synchronous removal and selective detection towards hydrazine, probably applying in superintending water quality and disposing wastewater.

Challenges and recent advancements of functionalization of two-dimensional nanostructured molybdenum trioxide and dichalcogenides

Atomically thin two-dimensional (2D) semiconductors are the thinnest functional semiconducting materials available today. Among them, both molybdenum trioxide and chalcogenides (MT&Ds) represent key components within the family of different 2D semiconductors for various electronic, optoelectronic and electrochemical applications due to their unique electronic, optical, mechanical and electrochemical properties. However, despite great progress in research dedicated to the development and fabrication of 2D MT&Ds observed within the last decade, there are significant challenges that affected their charge transport behavior and fabrication on a large scale as well as there is high dependence of the carrier mobility on the thickness. In this article, we review the recent progress in the carrier mobility engineering of 2D MT&Ds and elaborate devised strategies dedicated to the optimization of MT&D properties. Specifically, the latest physical and chemical methods towards the surface functionalization and optimization of the major factors influencing the extrinsic transport at the electrode-2D semiconductor interface are discussed.

Novel urchin-like FeCo oxide nanostructures supported carbon spheres as a highly sensitive sensor for hydrazine sensing application

Herein, we successfully fabricated a novel nanostructure based on hierarchical urchin-like FeCo oxide supported carbon spheres (FeCo Oxide/CSs) via a two-step hydrothermal method followed by a simple annealing step at 300 °C under air. It was found that such urchin-like FeCo Oxide/CSs structure exhibited superior catalytic activity towards hydrazine oxidation to CSs, Fe Oxide/CSs, Co Oxide/CSs, and FeCo Hydroxide/CSs material. In this regard, the FeCo Oxide/CSs displayed a wide linear detection range of 0.1-516.6 μM, low detection limit of 0.1 μM, and long-term stability. The material also showed good selectivity towards hydrazine detection in the presence of various interferences, such as uric acid, ascorbic acid, urea, dopamine, Na⁺, SO₄^2-, K⁺, and Cl-. The excellent sensing performance of the FeCo Oxide/CSs was assumed to the unique hierarchical urchin structure with the high density and uniformity of nano-sized FeCo Oxide nanoneedles, which produced massive electroactive sites and enhanced charge transfer ability. The achieved results implied that the FeCo Oxide/CSs may be a great candidate for sensitive hydrazine detection.