Overview of Polyvinyl Alcohol Nanocomposite Hydrogels for Electro‐Skin,Actuator, Supercapacitor and Fuel Cell

The properties of polyvinyl alcohol (PVA) nanocomposite hydrogels influenced by nanoparticles are reviewed. Various kinds of nanoparticles with excellent mechanical and electrical properties have been introduced into PVA hydrogel to produce stretchable and conductive PVA nanocomposite hydrogel. Understanding the mechanism between the matrix of PVA hydrogel and nanoparticles is therefore critical for the development of PVA nanocomposite hydrogels. This review focuses on the nanoparticles include carbon nanotubes, graphene oxide and metal nanoparticles, and describes the effects of nanoparticles on the mechanical and conductive properties of PVA nanocomposite hydrogels. A new promising area of soft stretchable PVA nanocomposite hydrogel is highlighted for possible applications. Finally, a brief outlook for future research is presented.     

2020 Roadmap on Carbon Materials for Energy Storage and Conversion

Carbon is a simple, stable and popular element with many allotropes. The carbon family members include carbon dots, carbon nanotubes, carbon fibers, graphene, graphite, graphdiyne and hard carbon, etc. They can be divided into different dimensions, and their structures can be open and porous. Moreover, it is very interesting to dope them with other elements (metal or non‐metal) or hybridize them with other materials to form composites. The elemental and structural characteristics offer us to explore their applications in energy, environment, bioscience, medicine, electronics and others. Among them, energy storage and conversion are extremely attractive, as advances in this area may improve our life quality and environment. Some energy devices will be included herein, such as lithium‐ion batteries, lithium sulfur batteries, sodium‐ion batteries, potassium‐ion batteries, dual ion batteries, electrochemical capacitors, and others. Additionally, carbon‐based electrocatalysts are also studied in hydrogen evolution reaction and carbon dioxide reduction reaction. However, there are still many challenges in the design and preparation of electrode and electrocatalytic materials. The research related to carbon materials for energy storage and conversion is extremely active, and this has motivated us to contribute with a roadmap on ‘Carbon Materials in Energy Storage and Conversion’.     

Electrochemistry in Carbon‐based Quantum Dots

Electrochemistry belongs to an important branch of chemistry that deals with the chemical changes produced by electricity and the production of electricity by chemical changes. Therefore, it can not only act a powerful tool for materials synthesis, but also offer an effective platform for sensing and catalysis. As extraordinary zero‐dimensional materials, carbon‐based quantum dots (CQDs) have been attracting tremendous attention due to their excellent properties such as good chemical stability, environmental friendliness, nontoxicity and abundant resources. Compared with the traditional methods for the preparation of CQDs, electrochemical (EC) methods offer advantages of simple instrumentation, mild reaction conditions, low cost and mass production. In return, CQDs could provide cost‐effective, environmentally friendly, biocompatible, stable and easily‐functionalizable probes, modifiers and catalysts for EC sensing. However, no specific review has been presented to systematically summarize both aspects until now. In this review, the EC preparation methods of CQDs are critically discussed focusing on CQDs. We further emphasize the applications of CQDs in EC sensors, electrocatalysis, biofuel cells and EC flexible devices. This review will further the experimental and theoretical understanding of the challenges and future prospective in this field, open new directions on exploring new advanced CQDs in EC to meet the high demands in diverse applications.     

Investigation of Structural Evolution of SnO2 Nanosheets towards Electrocatalytic CO2 Reduction

In‐depth understanding of the catalytic active sites is of paramount importance for the design of efficient electrocatalysts for CO₂ conversion. Here we highlight the structural evolution of SnO₂ nanosheets for electrocatalytic CO₂ reduction. The transformation of SnO₂ into metallic Sn would occur on the surface of catalyst during the catalytic process, followed by enhanced selectivity and activity for the conversion of CO₂ to HCOOH. Electrocatalytic characterization and structural analysis demonstrate that the metallic Sn derived from structural evolution plays a dominant role in the CO₂ reduction to HCOOH. This work deepens the understanding of the catalytic mechanism and provides a new pathway for the rational design of advanced electrocatalysts for CO₂ reduction.     

Obituary: Professor Dr.-Ing. Justus Mühlenpfordt

Abstract

The dose-dependent isotope fractionation during decarboxylation (¹³C/¹²C) amplifies the radiation effect in the relatively low dose range. The fractionation of the nitrogen isotopes during deamination (¹⁵N/¹⁴N) at the dose of 17 Gy was found to be smaller than that of decarboxylation.     

热囚禁离子系统中的两量子比特条件相位门的简单方案

提出了一个实现两离子量子逻辑门的简单方案。本方案使用了两个囚禁于线性阱的三能级离子。本方案不使用振动模作为数据总线,仅需要激光与离子的单个相互作用,因而相互作用时间变短,这点从退相干的角度看是很重要的,而且本方案对振动模的加热不敏感。     

Encapsulation of nanocrystals with responsive gels for spatial optical identification

A tripeptide (β-AspFF) gelator was designed and synthesised using solid-phase peptide synthesis. The as-prepared gelator formed a stable and clear multi-responsive gel in toluene solution. Encapsulating the quantum dots with β-AspFF effectively increased stability and antioxidisation ability which are beneficial for optical identification.