The synergetic effects of Ti3C2 MXene and Pt as co-catalysts for highly efficient photocatalytic hydrogen evolution over g-C3N4.

Co-catalyst loading provides an effective way to enhance the efficiency of photocatalysts for solar hydrogen production. From a sustainability point of view, it has immense scientific and technological values to explore more efficient co-catalytic systems by using multi-cocatalysts, because of potential synergetic effects between different components. Herein, the feasibility of using Ti3C2 MXene nanoparticles and Pt nanoclusters as dual co-catalysts to enhance the photoactivity of g-C3N4 for H2 production was investigated. Due to the improved electrical conductivity and increased reactive sites for photoreduction reactions, Ti3C2 and Pt co-modified photocatalysts exhibited a high photocatalytic hydrogen production activity of 5.1 mmol h-1 g-1. Compared to g-C3N4/Ti3C2 and g-C3N4/Pt, the 3- and 5-fold increased photoactivity demonstrated great potential of Ti3C2 MXene nanoparticles to construct high-performance photocatalysts. The synergetic effects between Ti3C2 and Pt were fundamentally investigated, indicating that the specific transfer of electrons not only contributed to the inhibited recombination of charge carriers but also resulted in good stability of heterostructured photocatalysts. Our results have demonstrated an approach worthy for the design and fabrication of high-efficiency heterostructures with superior photoactivity for hydrogen energy production.

Solution Combustion Synthesis of High-Performance Nano-LiFePO4/C Cathode Material from Cost-Effective Mixed Fuels.

Solution combustion synthesis (SCS) is considered as an efficient and energy-saving method for preparing LiFePO4/C composite material with the nanostructure (Nano-LiFePO4/C). In this study, Nano-LiFePO4/C cathode material was prepared using SCS using a cost-effective combination of urea and sorbitol as mixed fuels. The effect of mixed fuels on combustion behavior and microstructure as well as on electrochemical performance was studied using XRD, BET, SEM, TEM, and electrochemical characterization methods. Multiple characterization results indicated that the maximum temperature (Tm) and particle size were influenced by the usage of urea and sorbitol. The sample derived under optimum conditions exhibits a mesoporous nanostructure with a large surface specific area and attractive electrochemical performance with a discharge capacity of 153.5 mAh/g at 0.1 C, which shows strong potential for commercial applications in the future.

Solid-State Explosive Reaction for Nanoporous Bulk Thermoelectric Materials.

High-performance thermoelectric materials require ultralow lattice thermal conductivity typically through either shortening the phonon mean free path or reducing the specific heat. Beyond these two approaches, a new unique, simple, yet ultrafast solid-state explosive reaction is proposed to fabricate nanoporous bulk thermoelectric materials with well-controlled pore sizes and distributions to suppress thermal conductivity. By investigating a wide variety of functional materials, general criteria for solid-state explosive reactions are built upon both thermodynamics and kinetics, and then successfully used to tailor material's microstructures and porosity. A drastic decrease in lattice thermal conductivity down below the minimum value of the fully densified materials and enhancement in thermoelectric figure of merit are achieved in porous bulk materials. This work demonstrates that controlling materials' porosity is a very effective strategy and is easy to be combined with other approaches for optimizing thermoelectric performance.