Nankai University

About: Nankai University is a education organization based out in Tianjin, China. It is known for research contribution in the topics: Catalysis & Enantioselective synthesis. The organization has 42964 authors who have published 51866 publications receiving 1127896 citations. The organization is also known as: Nánkāi Dàxué.

Nonstoichiometric perovskite CaMnO(3-δ) for oxygen electrocatalysis with high activity.

Abstract: Perovskite oxides offer efficient and cheap electrocatalysts for both oxygen reduction reactions and oxygen evolution reactions (ORR/OER) in diverse oxygen-based electrochemical technologies. In this study, we report a facile strategy to enhance the electrocatalytic activity of CaMnO3 by introducing oxygen defects. The nonstoichiometric CaMnO(3-δ) (0 < δ ≤ 0.5) was prepared through thermal reduction of pristine perovskite microspheres and nanoparticles, which were synthesized from thermal-decomposition of carbonate precursors and the Pechini route, respectively. The as-prepared samples were analyzed by chemical titration, structural refinement, thermogravimetric analysis, and energy spectrometry. In 0.1 M KOH aqueous solution, the nonstoichiometric CaMnO(3-δ) with δ near 0.25 and an average Mn valence close to 3.5 exhibited the highest ORR activity (36.7 A g(-1) at 0.70 V vs RHE, with onset potential of 0.96 V), which is comparable to that of benchmark Pt/C. Density functional theory (DFT) studies and electrical conductivity measurement revealed that the enhanced ORR kinetics is due to facilitated oxygen activation and improved electrical properties. Besides high activity, the nonstoichiometric perovskite oxides showed respectable catalytic stability. Furthermore, the moderate oxygen-defective CaMnO(3-δ) (δ ≈ 0.25) favored the OER because of the improved electrical conductivity. This study makes nonstoichiometric CaMnO(3-δ) a promising active, inexpensive bifunctional catalytic material for reversible ORR and OER.

Ti2CO2 MXene: a highly active and selective photocatalyst for CO2 reduction

Abstract: Photocatalytic reduction of carbon dioxide (CO2) into hydrocarbons could promote the CO2 utilization and retard the greenhouse effect, which has gained much attention Due to high surface–bulk ratio, two-dimensional materials can be promising candidates for catalysis In this study, by means of first-principles computations, we have investigated the reduction of CO2 at the oxygen vacancy on MXene monolayers Among Ti2CO2, V2CO2 and Ti3C2O2, Ti2CO2 has exhibited the best catalytic performance for the reduction of CO2 The reaction pathway CO2 → HCOO → HCOOH was found to be favorable with an energy barrier of 053 eV The energy barriers of the reaction pathways for other single-carbon organic products were much higher, indicating high selectivity for HCOOH Moreover, we have proposed that CO and H2 can introduce sufficient oxygen vacancies on O-terminated MXene This study provides new insights into the design of catalysts for the reduction of CO2 and further widens the applications of MXene-based materials

Beyond yolk-shell nanoparticles: Fe3O4@Fe3C core@shell nanoparticles as yolks and carbon nanospindles as shells for efficient lithium ion storage.

Abstract: To well address the problems of large volume change and dissolution of Fe3O4 nanomaterials during Li+ intercalation/extraction, herein we demonstrate a one-step in situ nanospace-confined pyrolysis strategy for robust yolk–shell nanospindles with very sufficient internal void space (VSIVS) for high-rate and long-term lithium ion batteries (LIBs), in which an Fe3O4@Fe3C core@shell nanoparticle is well confined in the compartment of a hollow carbon nanospindle. This particular structure can not only introduce VSIVS to accommodate volume change of Fe3O4 but also afford a dual shell of Fe3C and carbon to restrict Fe3O4 dissolution, thus providing dual roles for greatly improving the capacity retention. As a consequence, Fe3O4@Fe3C–C yolk–shell nanospindles deliver a high reversible capacity of 1128.3 mAh g–1 at even 500 mA g–1, excellent high rate capacity (604.8 mAh g–1 at 2000 mA g–1), and prolonged cycling life (maintaining 1120.2 mAh g–1 at 500 mA g–1 for 100 cycles) for LIBs, which are much better than t...