Coupling Fe and Mo single atoms on hierarchical N-doped carbon nanotubes enhances electrochemical nitrogen reduction reaction performance

Electrochemical nitrogen reduction reaction(NRR)paves a new way to cost-efficient production of ammonia,but is still challenging in the sluggish kinetics caused by hydrogen evolution reaction competition and chemical inertness of N≡N bond.Herein,we report a“dual-site”strategy for boosting NRR performance.A high-performance catalyst is successfully constructed by anchoring isolated Fe and Mo atoms on hierarchical N doped carbon nanotubes through a facile self-sacrificing template route,which exhibits a remarkably improved NH3 yield rate of 26.8μg·h^(−1)·mg with 11.8%Faradaic efficiency,which is 2.5 and 1.6 times larger than those of Fe/NC and Mo/NC.The enhancement can be attributed to the unique hierarchical structure that profits from the contact of electrode and electrolyte,thus improving the mass and electron transport.More importantly,the in situ Fourier transform infrared spectroscopy(in situ FTIR)result firmly demonstrates the crucial role of the coupling of Fe and Mo atoms,which can efficiently boost the generation and transmission of*N2Hy intermediates,leading to an accelerated reaction rate.

Out-of-plane photoconductive and bulk photovoltaic effects in two-dimensionalα-In_(2)Se_(3)/Ta_(2)NiS_(5) ferroelectric heterojunctions

Two-dimensionalα-In_(2)Se_(3)exhibits simultaneous intercorrelated in-plane and out-of-plane polarization,making it a highly promising material for use in memories,synapses,sensors,detectors,and optoelectronic devices.With its narrow bandgap,α-In_(2)Se_(3)is particularly attractive for applications in photodetection.However,relatively little research has been conducted on the out-of-plane photoconductive and bulk photovoltaic effects inα-In_(2)Se_(3).This limits the potential ofα-In_(2)Se_(3)in the device innovation and performance modification.Herein,we have developed anα-In_(2)Se_(3)-based heterojunction with a transparent electrode of two-dimensional Ta_(2)NiS_(5).The out-of-plane electric field can effectively separate the photo-generated electron-hole pairs in the heterojunction,resulting in an out-of-plane responsivity(R),external quantum efficiency(EQE),and specific detectivity(D*)of 0.78 mA/W,10−3%and 1.14×10^(8)Jones,respectively.The out-of-plane bulk photovoltaic effect has been demonstrated by changes in the short circuit current(SCC)and open circuit voltage(V_(oc))with different optical power intensity and temperature,which indicates thatα-In_(2)Se_(3)-based heterojunctions has application potential in mid-far infrared light detection based on its out-of-plane photoconductive and bulk photovoltaic effects.Although the out-of-plane photoconductive and bulk photovoltaic effects are relatively lower than that of traditional materials,the findings pave the way for a better understanding of the out-of-plane characteristics of two-dimensionalα-In_(2)Se_(3)and related heterojunctions.Furthermore,the results highlight the application potential ofα-In_(2)Se_(3)in low-power device innovation and performance modification.

3D Printing Technology for Short-continuous Carbon Fiber Synchronous Reinforced Thermoplastic Composites:A Comparison between Towpreg Extrusion and In Situ Impregnation Processes

Three-dimensional(3D)printing of carbon fiber-reinforced thermoplastic composites(CFRTPs)provides an ef-fective method for manufacturing the CFRTPs parts with complex structures.To increase the mechanical per-formance of these parts,a 3D printing technology for short-continuous carbon fiber synchronous-reinforced thermoplastic composites(S/C-CFRTPs)has been proposed.However,the synchronous reinforcement that ex-isted only at particular positions led to a limited improvement in the mechanical performance of the 3D-printed S/C-CFRTP part,which made it challenging to meet the engineering requirements.To solve this problem,two methods for achieving synchronous reinforcement at all the positions of the 3D-printed S/C-CFRTP part are pro-posed.To determine a suitable printing process for the S/C-CFRTP part,a comprehensive comparison between the two methods was conducted through theoretical analysis and experimental verification,involving the print-ing mechanism,fiber content,impregnation percentage,and mechanical performance.The results indicated that the towpreg extrusion process was suitable for manufacturing the 3D-printed S/C-CFRTP part.Compared with the in situ impregnation process,the towpreg extrusion process led to a fiber content increase of approximately 7%and void rate reduction of approximately 6%,resulting in 19%and 20%increases in the tensile and flexural strengths of the 3D-printed S/C-CFRTPs,respectively.Additionally,an optimized process parameter setting for fabricating an S/C-CFRTP prepreg filament with excellent mechanical performance was proposed.The findings of this study can provide a new approach for further improving the mechanical performance of the 3D-printed advanced composites.