Hierarchically Porous Organic Materials Derived From Copolymers: Preparation and Electrochemical Applications

An electrochemical aptasensor for detection of carbofuran using gold nanoparticles decorated hierarchical porous carbon as an effective sensing platform

In this study, a novel electrochemical aptasensor for carbofuran (CBF) detection is prepared by gold nanoparticles decorated hierarchical porous carbon (Au@HPC). The prepared carbon materials show a three-dimensional hierarchical structure with a large specific surface area and a highly developed porous structure. Aptamers loading significantly improves when gold nanoparticles are embedded into the hierarchical porous carbon skeleton. Besides, Au@HPC modified electrode exhibits a large electroactive area and excellent electrochemical conductivity, serving as a promising platform for highly sensitive and selective electrochemical detection of CBF. The developed CBF electrochemical aptasensor shows a wide linear from 1.0 to 100000 pg/L with a detection limit of 0.5 pg/L, demonstrating an extraordinary sensitivity compared to other sensors for CBF detection. Additionally, the designed aptasensor was used to monitor the CBF in vegetable samples, with a recovery range from 98.4% to 104.8%. The results coincide with the standard test method, revealing its practicability in the food safety analysis.

Hierarchical Design in Nanoporous Metals

Hierarchically porous metals possess intriguing high accessibility of matter molecules and unique continuous metallic frameworks, as well as a high level of exposed active atoms. High rates of diffusion and fast energy transfer have been important and challenging goals of hierarchical design and porosity control with nanostructured metals. This review aims to summarize recent important progress toward the development of hierarchically porous metals, with special emphasis on synthetic strategies, hierarchical design in structure-function and corresponding applications. The current challenges and future prospects in this field are also discussed.

2D Redox-Active Covalent Organic Frameworks for Supercapacitors: Design, Synthesis, and Challenges

Due to the tunable skeletons, variable pore environments, and predesignable structures, covalent organic frameworks (COFs) can be served as a versatile platform to tailor redox activities for efficient energy storage. Redox-active COFs with specific functional groups can not only promote high-speed mass transport in the permanently open channels, but also provide dense active sites for reversible redox reactions so as to efficiently adsorb the electrolyte ions, thus becoming emerging and promising electroactive materials. This review summarizes the design principles and synthetic methods of redox-active COFs, with a focus on surveying the representative advances in supercapacitors. The key progress, major challenges, and future directions in this promising field are highlighted as well.

Tuneable Metamaterial-like Platforms for Surface-Enhanced Raman Scattering via Three-Dimensional Block Co-polymer-Based Nanoarchitectures

Surface-enhanced Raman spectroscopy (SERS) pushes past the boundaries and inherent weaknesses of Raman spectroscopy, with a great potential for a broad range of applications particularly, for sensing. Yet, current real world applications are limited due to poor reproducibility, low-throughput, and stability issues. Here, we present the design and fabrication of self-assembly guided structures based on adjustable block co-polymer (BCP) nanomorphologies and demonstrate reproducible SERS enhancement across large areas. Golden three-dimensional (3D) nanostructured morphologies with controllable dimensions and morphologies exhibit high chemical stability, enhanced plasmonic properties and are highly suitable for SERS substrates due to the strong enhancement of the electromagnetic field. Adjustable, free standing porous nanostructures, continuous in 3D space are achieved by removal of selected BCP constituents. Four BCP morphologies and the corresponding achievable enhancement factors are investigated at 633 and 785 nm excitation wavelengths. The choice of excitation laser is shown to greatly affect the observed signal enhancement, highlighting the sensitivity of the technique to the underlying surface architecture and length scales. By using BCP assemblies, it is possible to reliably tune these parameters to match specific applications, thus bridging the gap toward the realization of applied metamaterials. The fabricated SERS platforms via three-dimensional block co-polymer-based nanoarchitectures provide a recipe for intelligent engineering and design of optimized SERS-active substrates for utilization in the Raman spectroscopy-based devices toward enabling the next-generation technologies fulfilling a multitude of criteria.