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.

Recent Advances in Perovskite Oxides as Electrode Materials for Nonaqueous Lithium–Oxygen Batteries

Abstract: Lithium–oxygen batteries are considered the next-generation power sources for many applications. The commercialization of this technology, however, is hindered by a variety of technical hurdles, including low obtainable capacity, poor energy efficiency, and limited cycle life of the electrodes, especially the cathode (or oxygen) electrode. During the last decade, tremendous efforts have been devoted to the development of new cathode materials. Among them, perovskite oxides have attracted much attention due to the extraordinary tunability of their compositions, structures, and functionalities (e.g., high electrical conductivities and catalytic activities), demonstrating the potential to achieve superior battery performance. This article focuses on the recent advances of perovskite oxides as the electrode materials in nonaqueous lithium–oxygen batteries. The electrochemical mechanisms of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on the surface of perovskite oxides are first summarized. Then, the effect of nanostructure and morphology on ORR and OER activities is reviewed, from nanoparticles to hierarchical porous structures. Moreover, perovskite-oxide-based composite electrodes are discussed, highlighting the enhancement in electrical conductivities, catalytic activities, and durability under realistic operating conditions. Finally, the remaining challenges and new directions for achieving rational design of perovskite oxides for nonaqueous lithium–oxygen batteries are outlined and discussed.

High activity and durability of novel perovskite electrocatalysts for water oxidation

Abstract: Development of highly active and cost-effective electrocatalysts is central to the large-scale electrolysis of water for renewable energy generation. Perovskite oxides are a group of promising candidates to lower the oxygen evolution reaction (OER) barriers in water splitting and further improvement of their activity and durability is an important objective. Here we report scandium and niobium cation (Sc3+ and Nb5+) doped strontium cobaltite perovskites (SrScxNbyCo1−x−yO3−δ) as a family of highly active and durable electrocatalysts for the OER in alkaline solution. These perovskites not only manifest up to a factor of 50 increase of the intrinsic activity compared to the gold-standard OER electrocatalysts (such as IrO2 and RuO2) and a factor of 5.8 enhancement to the perovskite-Ba0.5Sr0.5Co0.8Fe0.2O3−δ at an overpotential of 0.35 V, but also, more importantly, show excellent durability in alkaline solutions under operation.

Synthesis of zeolitic imidazolate framework-78 molecular-sieve membrane: defect formation and elimination

Abstract: Metal–organic frameworks (MOFs) are ideal micro- and mesoporous materials for molecular separation. A defect-free MOF membrane supported on a porous substrate is required for high separation performance, however it is rather difficult to eliminate the micro-defects or intercrystalline gaps in the membranes. In this work, a ZIF-78 membrane was synthesized on a porous ZnO support. The defect formation mechanism in the membrane was illustrated by in situ thermal expansion analysis. A novel strategy was proposed to eliminate not only the macroscopic defects but also the intercrystalline gaps in the membrane by controlling the diffusion of solvent molecules through the channels of the ZIF-78 crystal. The ZIF-78 membrane exhibited high performance in separating H2. The ideal selectivity and mixture separation factor of H2–CO2 are 11.0 and 9.5, respectively. The approach reported in this paper offers an efficient and universal strategy for the facile synthesis of high-quality MOF membranes on porous supports.