Jilin University

About: Jilin University is a education organization based out in Changchun, China. It is known for research contribution in the topics: Catalysis & Apoptosis. The organization has 101453 authors who have published 88966 publications receiving 1444456 citations. The organization is also known as: Jílín Dàxué.

Coupling Mo2C with Nitrogen‐Rich Nanocarbon Leads to Efficient Hydrogen‐Evolution Electrocatalytic Sites

Abstract: In our efforts to obtain electrocatalysts with improved activity for water splitting, meticulous design and synthesis of the active sites of the electrocatalysts and deciphering how exactly they catalyze the reaction are vitally necessary. Herein, we report a one-step facile synthesis of a novel precious-metal-free hydrogen-evolution nanoelectrocatalyst, dubbed Mo2C@NC that is composed of ultrasmall molybdenum carbide (Mo2C) nanoparticles embedded within nitrogen-rich carbon (NC) nanolayers. The Mo2C@NC hybrid nanoelectrocatalyst shows remarkable catalytic activity, has great durability, and gives about 100 % Faradaic yield toward the hydrogen-evolution reaction (HER) over a wide pH range (pH 0–14). Theoretical calculations show that the Mo2C and N dopants in the material synergistically co-activate adjacent C atoms on the carbon nanolayers, creating superactive nonmetallic catalytic sites for HER that are more active than those in the constituents.

Atomic Modulation of FeCo–Nitrogen–Carbon Bifunctional Oxygen Electrodes for Rechargeable and Flexible All-Solid-State Zinc–Air Battery

Abstract: Rational design and exploration of robust and low-cost bifunctional oxygen reduction/evolution electrocatalysts are greatly desired for metal–air batteries. Herein, a novel high-performance oxygen electrode catalyst is developed based on bimetal FeCo nanoparticles encapsulated in in situ grown nitrogen-doped graphitic carbon nanotubes with bamboo-like structure. The obtained catalyst exhibits a positive half-wave potential of 0.92 V (vs the reversible hydrogen electrode, RHE) for oxygen reduction reaction, and a low operating potential of 1.73 V to achieve a 10 mA cm−2 current density for oxygen evolution reaction. The reversible oxygen electrode index is 0.81 V, surpassing that of most highly active bifunctional catalysts reported to date. By combining experimental and simulation studies, a strong synergetic coupling between FeCo alloy and N-doped carbon nanotubes is proposed in producing a favorable local coordination environment and electronic structure, which affords the pyridinic N-rich catalyst surface promoting the reversible oxygen reactions. Impressively, the assembled zinc–air batteries using liquid electrolytes and the all-solid-state batteries with the synthesized bifunctional catalyst as the air electrode demonstrate superior charging–discharging performance, long lifetime, and high flexibility, holding great potential in practical implementation of new-generation powerful rechargeable batteries with portable or even wearable characteristic.

Transparent dense sodium.

Abstract: Under pressure, metals exhibit increasingly shorter interatomic distances. Intuitively, this response is expected to be accompanied by an increase in the widths of the valence and conduction bands and hence a more pronounced free-electron-like behaviour. But at the densities that can now be achieved experimentally, compression can be so substantial that core electrons overlap. This effect dramatically alters electronic properties from those typically associated with simple free-electron metals such as lithium (Li; refs 1-3) and sodium (Na; refs 4, 5), leading in turn to structurally complex phases and superconductivity with a high critical temperature. But the most intriguing prediction-that the seemingly simple metals Li (ref. 1) and Na (ref. 4) will transform under pressure into insulating states, owing to pairing of alkali atoms-has yet to be experimentally confirmed. Here we report experimental observations of a pressure-induced transformation of Na into an optically transparent phase at approximately 200 GPa (corresponding to approximately 5.0-fold compression). Experimental and computational data identify the new phase as a wide bandgap dielectric with a six-coordinated, highly distorted double-hexagonal close-packed structure. We attribute the emergence of this dense insulating state not to atom pairing, but to p-d hybridizations of valence electrons and their repulsion by core electrons into the lattice interstices. We expect that such insulating states may also form in other elements and compounds when compression is sufficiently strong that atomic cores start to overlap strongly.

Highly Oriented Low-Dimensional Tin Halide Perovskites with Enhanced Stability and Photovoltaic Performance

Abstract: The low toxicity and a near-ideal choice of bandgap make tin perovskite an attractive alternative to lead perovskite in low cost solar cells. However, the development of Sn perovskite solar cells has been impeded by their extremely poor stability when exposed to oxygen. We report low-dimensional Sn perovskites that exhibit markedly enhanced air stability in comparison with their 3D counterparts. The reduced degradation under air exposure is attributed to the improved thermodynamic stability after dimensional reduction, the encapsulating organic ligands, and the compact perovskite film preventing oxygen ingress. We then explore these highly oriented low-dimensional Sn perovskite films in solar cells. The perpendicular growth of the perovskite domains between electrodes allows efficient charge carrier transport, leading to power conversion efficiencies of 5.94% without the requirement of further device structure engineering. We tracked the performance of unencapsulated devices over 100 h and found no apprec...

Photoluminescent metal-organic polymer constructed from trimetallic clusters and mixed carboxylates.

Abstract: The solvothermal reaction of zinc acetate dihydrate with a mixture of benzene-1,4-dicarboxylic acid (H(2)BDC) and benzene-1,3,5-tricarboxylic acid (H(3)BTC) in a solution containing N,N'-dimethylformamide (DMF), absolute ethanol, and chlorobenzene gave rise to a metal-organic polymer, Zn(3).BDC.2BTC.2NH(CH(3))(2).2NH(2)(CH(3))(2). The structure of this polymer possesses a unique three-dimensional framework with tri-zinc clusters, and BDC and BTC units colinking the clusters. Moreover, this metal-organic polymer exhibits strong photoluminescence at room temperature, and the main emission band is at about 430 nm (lambda(ex) = 325 nm). Crystal data for this compound (C(17)H(20)N(2)O(8)Zn(1.5)): monoclinic, space group P2(1)/n, cell dimensions a = 11.6171(3) A, b = 14.2456(4) A, c = 12.6426(3) A, beta = 107.030(2) degrees, V = 2000.51(9) A(3), and Z = 4.