With the continuous development and progress of materials science, increasingly more attention has been paid to the new technology of powder synthesis and material preparation. The hydrothermal method is a promising liquid phase preparation technology that has developed rapidly during recent years. It is widely used in many fields, such as the piezoelectric, ferroelectric, ceramic powder, and oxide film fields. The hydrothermal method has resulted in many new methods during the long-term research process, such as adding other force fields to the hydrothermal condition reaction system. These force fields mainly include direct current, electric, magnetic (autoclaves composed of non-ferroelectric materials), and microwave fields. Among them, the microwave hydrothermal method, as an extension of the hydrothermal reaction, cleverly uses the microwave temperature to compensate for the lack of temperature in the hydrothermal method, allowing better practical application. This paper reviews the development of the hydrothermal and microwave hydrothermal methods, introduces their reaction mechanisms, and focuses on the practical application of the two methods.

https://www.mdpi.com/1996-1944/12/7/1177/pdf

Conventional and Microwave Hydrothermal Synthesis and Application of Functional Materials: A Review

BiVO4, Bi2WO6 and Bi2MoO6 photocatalysis: A brief review

/pdf/metal-oxide-nanostructures-for-sensor-applications-3fe10u79mn.pdf

Metal oxide nanostructures for sensor applications

Manganese dioxides, inorganic materials which have been used in industry for more than a century, now find great renewal of interest for storage and conversion of energy applications. In this review article, we report the properties of MnO2 nanomaterials with different morphologies. Techniques used for the synthesis, structural, physical properties, and electrochemical performances of periodic and aperiodic frameworks are discussed. The effect of the morphology of nanosized MnO2 particles on their fundamental features is evidenced. Applications as electrodes in lithium batteries and supercapacitors are examined.

Nanostructured MnO2 as Electrode Materials for Energy Storage

In the past decades, there has been a strong incentive to develop electric vehicles by the introduction of batteries to reduce the dependence on petroleum oil and mitigate the tailpipe emissions. Lithium-ion batteries have dominated the electric vehicle market due to their high capacity and energy efficiency. However, the insufficient energy density of lithium-ion batteries is still a big problem for the development of electric vehicles. Metal–air batteries have been considered among the most promising power sources for electric vehicles due to some attractive advantages such as high energy density, low cost and environmental friendliness. One of the most important issues for metal–air batteries is developing oxygen reduction reaction catalysts with high catalytic activity and stability. Transition metal oxides are a series of important catalysts for the oxygen reduction reaction in alkaline solution. The purpose of this paper is to provide a comprehensive review of the recent progress in transition metal oxide-type catalysts for the ORR in aqueous media, including simple transition metal oxide-type catalysts, perovskite-type catalysts, spinel-type catalysts and other ternary transition metal oxides catalysts (such as double perovskite oxides, pyrochlore oxides, Ruddlesden–Popper oxides, LiCoO2-related oxides, and Mn-based mullite oxides). Moreover, we also discuss the factors influencing the transition metal oxide-type catalysts for the ORR in metal–air batteries with aqueous electrolytes.

Dongfeng Shi

Papers

Hydrothermal synthesis of urchin-like MnO2 nanostructures and its electrochemical character for supercapacitor

{10–12} Twins across twin boundaries traced by in situ EBSD

Hydrothermal synthesis of hierarchical SnO2 nanostructures made of superfine nanorods for smart gas sensor

Twinning behaviors of a rolled AZ31 magnesium alloy under multidirectional loading

The effect of twin–twin interaction in Mg3Al1Zn alloy during compression