Current Trends in Nanomaterials for Metal Oxide-Based Conductometric Gas Sensors: Advantages and Limitations—Part 2: Porous 2D Nanomaterials

This article discusses the features of the synthesis and application of porous two-dimensional nanomaterials in developing conductometric gas sensors based on metal oxides. It is concluded that using porous 2D nanomaterials and 3D structures based on them is a promising approach to improving the parameters of gas sensors, such as sensitivity and the rate of response. The limitations that may arise when using 2D structures in gas sensors intended for the sensor market are considered

Synthesis of Birnessite Structure Layers at the Solution–Air Interface and the Formation of Microtubules from Them

H_<i>x</i>MnO₂·<i>n</i>H₂O layers have been successfully produced through a facile low-temperature process at the solution–air interface without using any templates. The crystalline structures of layers can be tuned by the compositions and the pH of the growth solutions. The analysis of birnessite-like layers indicates that they are formed by nanosheets approximately 4–6 nm thick that are oriented for the most part normally to the interface. Our results demonstrated that 1–3-μm-thick layers can roll up into microtubules 20 to 100 μm in diameter and up to 10 mm long. The hypothesis explaining the formation of the microtubular structures is assumed

The Effect of the Open Vase-like Microcapsules Formation with NiFe Double-Hydroxide Walls during Hydrolysis of the Mixture NiSO₄ and FeSO₄ Salt Solution Microdroplets Deposited on the Alkaline Solution Surface

In this work, the conditions for the synthesis of open vase-like microcapsules with a size of 1–5 μm and 20–40 nm walls of NiFe0.3(OH)x layered double hydroxide were studied. These microcapsules were obtained by the rapid hydrolysis of microdroplets of a solution of a mixture of NiSO4 and FeSO4 salts at the surface of an alkali solution. A hypothetical model of successive chemical processes occurring at the interface during synthesis is presented. The features of the “rim” formation around each microcapsule hole from the wall material with a peculiar nozzle-like shape are noted. These microcapsules can be transferred to the surface of a nickel foil using the Langmuir–Schaefer (LS) method. During the transfer process, they are fixed to the surface in an oriented position with a “rim” that contacts the nickel surface. It was established that electrodes made of such a foil with a layer of microcapsules exhibit active electrocatalytic properties in the oxygen evolution reaction during the electrolysis of water in an alkaline medium

A feasible interlayer strategy for simultaneous light and heat management in photothermal catalysis

Summary: Photothermal conversion represents one crucial approach for solar energy harvesting and its exploitation as a sustainable alternative to fossil fuels; however, an efficient, cost-effective, and generalized approach to enhance the photothermal conversion processes is still missing. Herein, we develop a feasible and efficient photothermal conversion strategy that achieves simultaneous light and heat management using supported metal clusters and WSe2 interlayer toward enhanced CO2 hydrogenation photothermal catalysis. The interlayer can simultaneously reduce heat loss in the catalytic layer and improve light absorption, leading to an 8-fold higher CO2 conversion rate than the controls. The optical and thermal performance of WSe2 interlayered catalysts on different substrates was quantified using Raman spectroscopy. This work demonstrates a feasible and generalized approach for effective light and heat management in solar harvesting. It also provides important design guidelines for efficient photothermal converters that facilitate the remediation of the energy and environmental crises faced by humans