Yingqiao Zhou,Bowen Yang,Richard L Smith Jr.,Yaqiong Su,Xinhua Qi
The development of recyclable heterogeneous bifunctional catalysts for the efficient conversion of cellulose into high-value platform chemicals is still a significant challenge. Herein, the preparation of carbon-nanosheet-encapsulated nickel phosphide catalysts was performed via solvent evaporation self-assembly and alkali activation, and the as-synthesized catalyst efficiently (3 h) hydrolyzes and hydrogenates microcrystalline cellulose to sorbitol with a sorbitol yield exceeding 90%. As a bifunctional catalyst, nickel phosphide (Niδ+–Pδ–) facilitates the heterolytic cleavage of H2, simultaneously generating in situ acidic Hδ+ species for hydrolysis and hydridic Hδ– species for the hydrogenation of C═O bonds. Unlike conventional catalysts with spatially separated functionalities, this concurrent process avoids intermediate accumulation and side reactions during cellulose conversion. Furthermore, encapsulation by carbon nanosheets suppresses phosphorus leaching under hydrothermal conditions, endowing the catalyst with balanced durability and activity. This work provides fundamental insights into hydrogen activation by transition metal phosphides and advances the design of bifunctional catalysts integrating both acidic and hydrogenation functionalities.
Sodium-ion batteries (SIBs) have recently attracted increasing attention as the promising alternative to lithium-ion batteries due to their multiple advantages of abundant reserves and low cost. However, the development of highly desirable anode materials suitable for SIBs is still hampered by a rather low capacity, poor rate capability, and cycling stability. Herein, a deliberate design to implement reliable and simple fabrication of an inverse opal structured nanohybrid of carbon-confined various transition metal sulfides quantum dots (QDs) is presented. Comprehensive characterizations demonstrate that the hybrids hold a 3D architecture with uniform dispersion of QDs in a conductive carbon matrix that in turn encapsulates these quantum dots. With Co 9 S 8 as an example, such a unique architecture, when applied as the anode of SIBs, endows the hybrids with multiple advantages including a high reversible specific capacity, extraordinary high rate capability, and excellent durability over 2000 cycles charging–discharging process.
Yongdong Liu,Zengwei Pang,MiaoMiao Liu,Quanxing Liao,Yunfeng Li,Xiaohui Niu,Hongxia Li,Kunjie Wang
As one of the promising alternatives for high energy-power supplying system, sodium ion hybrid capacitors (SIHCs) still remain a challenge towards seeking robust anode materials for hosting larger Na + . Cobalt sulfides are expected to be desired anode material due to its high capacity and superior thermal stability, but the application is hindered by the huge volume change. Herein, a hollow core-shell architectural Co 9 S 8 dodecahedron with dual‑carbon confinement (Co 9 S 8 /C@CNPS) is fabricated by controllable pyrolysis of ZIF-67 assisted with polymer. The unique structural features of small particle size, ample surface heteroatom doping, hollow architecture and dual‑carbon confinement can effectively shorten ions/electron transport path, offer abundant active sites as well as relax volume strain upon cycling. Consequently, the fast kinetic behavior and robust host structure endow Co 9 S 8 /C@CNPS with impressive performance for Na + storage. By integrating Co 9 S 8 /C@CNPS anode with a tobacco-derived biomass porous carbon (DTPC) cathode, the as-assembled SIHC demonstrates a high energy density of 96.5 W h kg −1 , high power supplying of 21 kW kg −1 and a long cycling stability with high capacity retention of 97.98 % after 10,000 cycles at 1 A g −1 . This work may shed light on the role of the structural engineering in electrode materials design.
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