Rationally Designed Three‐Layered Cu2S@Carbon@MoS2 Hierarchical Nanoboxes for Efficient Sodium Storage

Hybrid materials, integrating the merits of individual components, are ideal structures for efficient sodium storage. However, the construction of hybrid structures with decent physical/electrochemical properties is still challenging. Now, the elaborate design and synthesis of hierarchical nanoboxes composed of three‐layered Cu₂S@carbon@MoS₂ as anode materials for sodium‐ion batteries is reported. Through a facile multistep template‐engaged strategy, ultrathin MoS₂ nanosheets are grown on nitrogen‐doped carbon‐coated Cu₂S nanoboxes to realize the Cu₂S@carbon@MoS₂ configuration. The design shortens the diffusion path of electrons/Na⁺ ions, accommodates the volume change of electrodes during cycling, enhances the electric conductivity of the hybrids, and offers abundant active sites for sodium uptake. By virtue of these advantages, these three‐layered Cu₂S@carbon@MoS₂ hierarchical nanoboxes show excellent electrochemical properties in terms of decent rate capability and stable cycle life.     

Unusual Formation of CoSe@carbon Nanoboxes,which have an Inhomogeneous Shell,for Efficient Lithium Storage

Hybrid hollow nanostructures with tailored shell architectures are attractive for electrochemical energy storage applications. Starting with metal–organic frameworks (MOFs), we demonstrate a facile formation of hybrid nanoboxes with complex shell architecture where a CoSe‐enriched inner shell is intimately confined within a carbon‐enriched outer shell (denoted as CoSe@carbon nanoboxes). The synthesis is realized through manipulation of the template‐engaged reaction between Co‐based zeolitic imidazolate framework (ZIF‐67) nanocubes and Se powder at elevated temperatures. By virtue of the structural and compositional features, these unique CoSe@carbon nanoboxes manifest excellent lithium‐storage performance in terms of high specific capacity, exceptional rate capability, excellent cycling stability, and high initial Coulombic efficiency.     

Synthesis of Copper‐Substituted CoS2@CuxS Double‐Shelled Nanoboxes by Sequential Ion Exchange for Efficient Sodium Storage

The construction of hybrid architectures for electrode materials has been demonstrated as an efficient strategy to boost sodium‐storage properties because of the synergetic effect of each component. However, the fabrication of hybrid nanostructures with a rational structure and desired composition for effective sodium storage is still challenging. In this study, an integrated nanostructure composed of copper‐substituted CoS₂@Cu_xS double‐shelled nanoboxes (denoted as Cu‐CoS₂@Cu_xS DSNBs) was synthesized through a rational metal–organic framework (MOF)‐based templating strategy. The unique shell configuration and complex composition endow the Cu‐CoS₂@Cu_xS DSNBs with enhanced electrochemical performance in terms of superior rate capability and stable cyclability.     

Enhanced Multiple Anchoring and Catalytic Conversion of Polysulfides by Amorphous MoS3 Nanoboxes for High-Performance Li-S Batteries

The practical implementation of lithium–sulfur batteries is obstructed by poor conductivity, sluggish redox kinetics, the shuttle effect, large volume variation, and low areal loading of sulfur electrodes. Now, amorphous N-doped carbon/MoS₃ (NC/MoS₃) nanoboxes with hollow porous architectures have been meticulously designed as an advanced sulfur host. Benefiting from the enhanced conductivity by the N-doped carbon, reduced shuttle effect by the strong chemical interaction between unsaturated Mo and lithium polysulfides, improved redox reaction kinetics by the catalytic effect of MoS₃, great tolerance of volume variation and high sulfur loading arising from flexible amorphous materials with hollow-porous structures, the amorphous NC/MoS₃ nanoboxes enabled sulfur electrodes to deliver a high areal capacity with superior rate capacity and decent cycling stability. The synthetic strategy can be generalized to fabricate other amorphous metal sulfide nanoboxes.     

Enhanced Multiple Anchoring and Catalytic Conversion of Polysulfides by Amorphous MoS3 Nanoboxes for High‐Performance Li‐S Batteries

The practical implementation of lithium–sulfur batteries is obstructed by poor conductivity, sluggish redox kinetics, the shuttle effect, large volume variation, and low areal loading of sulfur electrodes. Now, amorphous N‐doped carbon/MoS₃ (NC/MoS₃) nanoboxes with hollow porous architectures have been meticulously designed as an advanced sulfur host. Benefiting from the enhanced conductivity by the N‐doped carbon, reduced shuttle effect by the strong chemical interaction between unsaturated Mo and lithium polysulfides, improved redox reaction kinetics by the catalytic effect of MoS₃, great tolerance of volume variation and high sulfur loading arising from flexible amorphous materials with hollow‐porous structures, the amorphous NC/MoS₃ nanoboxes enabled sulfur electrodes to deliver a high areal capacity with superior rate capacity and decent cycling stability. The synthetic strategy can be generalized to fabricate other amorphous metal sulfide nanoboxes.     

Creation of Al-Enriched Mesoporous ZSM-5 Nanoboxes with High Catalytic Activity: Converting Tetrahedral Extra-Framework Al into Framework Sites by Post Treatment

ZSM-5 zeolite nanoboxes with accessible meso-micro-pore architecture and strong acid sites are important in relevant heterogeneous catalysis suffering from mass transfer limitations and weak acidities. Rational design of parent zeolites with concentrated and non-protective coordination of Al species can facilitate post-synthetic treatment to produce mesoporous ZSM-5 nanoboxes. In this work, a simple and effective method was developed to convert parent MFI zeolites with tetrahedral extra-framework Al into Al-enriched mesoporous ZSM-5 nanoboxes with low silicon-to-aluminium ratios of ≈16. The parent MFI zeolite was prepared by rapid ageing of the zeolite sol gel synthesis mixture. The accessibility to the meso-micro-porous intra-crystalline network was probed systematically by comparative pulsed field gradient nuclear magnetic resonance diffusion measurements, which, together with the strong acidity of nanoboxes, provided superb catalytic activity and longevity in hydrocarbon cracking for propylene production.     

拓扑相变制备具有拓宽可见光响应范围的Ti3+自掺杂3D空盒状TiO2

TiO2广泛用作半导体光催化材料, 但由于自身对光利用率低(只吸收紫外光)、禁带宽度较大、光生载流子复合率极高, 限制了它在相关领域的应用. 为此, 设计了Ti3+离子自掺杂来克服TiO2半导体材料的上述缺点, 进而提高其光催化活性. 在不引入其他元素的情况下, 以TiOF2为原料, Zn粉为还原剂, 在水热条件下采用拓扑相变法原位制备了具有可见光响应的Ti3+自掺杂空盒状TiO2(记为Ti3+/TiO2)催化剂材料. 掺杂金属离子可以改变半导体TiO2的结晶度和产生晶格缺陷, 形成电子或空穴的捕获中心, 影响电子-空穴对的复合; 同时, 掺杂金属离子产生的晶格缺陷有利于Ti3+和氧空位的形成, 有利于提高TiO2的量子效率. Ti3+掺杂是一种既清洁又未引入其他金属离子的掺杂改性方法, 它能有效保持催化剂的结构和形貌不受其他金属离子的影响. 总之, 金属离子掺杂有效拓展了TiO2的光吸收范围, 并极大地提高了TiO2的光催化活性.本文研究了不同量的还原剂对催化剂空盒状TiO2结构形貌影响, 以及在可见光下光催化降解罗丹明B反应性能, 发现Ti3+/TiO2催化剂均拥有非常好的光催化活性, 其中R0.25催化剂在可见光下120 min, RhB降解率达到96%, 是TiO2的4倍多. 且可循环使用5次的光催化循环降解实验后, 表现出较高的稳定性. 催化剂经过Ti3+自掺杂后, 对催化剂自身的空盒状结构形貌并无很大的影响, 随着还原剂Zn粉的量增加, Ti4+还原形成Ti3+数量增加, 导致形成更多的氧空位. 皆为锐钛矿型TiO2,与未掺杂Ti3+的TiO2比较发现, 自掺杂Ti3+的TiO2的(105)XRD衍射峰越来越尖锐, (004)衍射峰越来越宽. 随着还原剂Zn粉质量的逐渐增加, 催化剂的光响应范围拓宽到可见光区, 且逐渐增强. 这说明Ti3+的掺杂不仅提高了TiO2在可见光的响应能力, 也提高了TiO2在紫外光范围的响应能力. 另外, 掺杂后的TiO2禁带宽度的减小, 使其价带上的电子更容易被可见光激发, 产生更多的电子-空穴对参与光催化反应, 从而提高TiO2的光催化效率.