Nanjing Tech University

About: Nanjing Tech University is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Catalysis & Membrane. The organization has 21827 authors who have published 21794 publications receiving 364050 citations. The organization is also known as: Nangongda & Nánjīng Gōngyè Dàxúe.

Planar pentacoordinate carbons

Abstract: Carbon centres in typical organic molecules have a coordination number that can reach a maximum of four, in which case the bonded atoms are situated at the vertices of a tetrahedron. Exceptions to those two structural rules have been posited and examined for decades, and planar tetracoordinate carbon (ptC) species are notable molecules that violate the second rule. There is continued interest in experimental and theoretical studies of ptCs, as well as emerging molecules that contain planar pentacoordinate carbon (ppC) and planar hexacoordinate carbon (phC) atoms, species that violate both structural rules. This Review describes recent progress in the theoretical prediction of viable entities that contain ppC centres. The first such molecule reported, the D5h-symmetric ppC species CAl5+, was followed by a series of predicted ppC species that could be obtained by substituting the Al centres for other heteroatoms. More complicated ppC systems have also been suggested, including metallocene-stabilized ppCs and quasi-ppCs embedded within cage structures or 2D materials. To date, computational studies have identified at least 65 local and 39 global minimum energy structures that contain ppCs or quasi-ppCs. The general design principles for ptC-centred candidate structures include delocalization of the central C 2pz lone electron pair, ensuring an 18 valence electron count and allowing for strong electron delocalization. These principles have been extended to ppC systems with some success. It is hard to predict the extent to which the coordination number of planar C can be increased because it depends not only on the valence and size of C but also on the size of the atoms bonded to it and the mode of bonding. Although a few energetically low-lying planar hexacoordinate and heptacoordinate C species have been identified computationally, none have been observed experimentally. Building on the theoretical prediction and experimental realization of planar tetracoordinate carbons, there has been great progress in the theoretical prediction of species containing planar pentacoordinate carbon (ppC) centres. From simple clusters such as CAl5+ to complicated ppCs in 2D materials, this Review summarizes the ppC-containing species predicted to date and the design principles behind them.

Achieving stable and efficient water oxidation by incorporating NiFe layered double hydroxide nanoparticles into aligned carbon nanotubes

Abstract: A facile and scalable co-precipitation method is developed to prepare stable colloidal NiFe-LDH nanoparticles at room temperature. We further scrolled NiFe-LDH nanoparticles into well-aligned multi-walled carbon nanotube (MWCNT) sheets to form binder-free hybrid microfiber electrodes, which showed excellent OER activity, reaching 180 mA cm−2 at a small overpotential of 255 mV with outstanding durability.

Defect engineering of oxide perovskites for catalysis and energy storage: synthesis of chemistry and materials science.

Abstract: Oxide perovskites have emerged as an important class of materials with important applications in many technological areas, particularly thermocatalysis, electrocatalysis, photocatalysis, and energy storage. However, their implementation faces numerous challenges that are familiar to the chemist and materials scientist. The present work surveys the state-of-the-art by integrating these two viewpoints, focusing on the critical role that defect engineering plays in the design, fabrication, modification, and application of these materials. An extensive review of experimental and simulation studies of the synthesis and performance of oxide perovskites and devices containing these materials is coupled with exposition of the fundamental and applied aspects of defect equilibria. The aim of this approach is to elucidate how these issues can be integrated in order to shed light on the interpretation of the data and what trajectories are suggested by them. This critical examination has revealed a number of areas in which the review can provide a greater understanding. These include considerations of (1) the nature and formation of solid solutions, (2) site filling and stoichiometry, (3) the rationale for the design of defective oxide perovskites, and (4) the complex mechanisms of charge compensation and charge transfer. The review concludes with some proposed strategies to address the challenges in the future development of oxide perovskites and their applications.