Nano-engineered catalysts for high-performance oxygen reduction reaction

The efficient energy conversion of fuel cells is greatly constrained by the slow oxygen reduction reac tion(ORR)kinetics,which necessitates the use of highly active metal catalysts such as platinum(Pt).The critical challenge limiting large-scale usage of Pt is the capital cost that can be addressed through a pro totypical approach by embedding metal nanoparticles(NPs),e.g.,Pt NPs,in the conductive framework However,previously reported embedding approaches are sophisticated and suffer from limited yields leading to higher chemical process costs and remaining distant from commercial viability.Here,we re port a facile,cost-effective and time-efficient structural tuning approach to synthesizing ultrafine Pt NP impregnated within a conductive and highly porous carbon framework via a microwave-assisted polyo reduction method.Pt NPs with a uniform size of~2.27 nm can be successfully integrated within the pore of the carbon framework,enabling homogeneous dispersion.Benefiting from these highly dispersed and ultrafine Pt NPs,the electrochemical surface area(ECSA)is improved to 142.98 m^(2)/gPt,2.25 times highe than that of the commercial counterpart(63.52 m^(2)/gPt).Furthermore,our structurally optimized catalys composite features a remarkably catalytic activity with a high half-wave potential(E_(1/2))of 0.895 V and an improved mass activity(MA)of 0.2289 A/mgPt,2.39-fold improvement compared to the commercia counterpart.In addition,orthogonal experiments were designed to identify the key process parameter for fabricating Pt/C catalysts,offering insights for scaled-up and industrial production.

3D anchoring structured for LiFe_(0.5)Mn_(0.5)PO_(4)@cornstalk-C cathode materials

The organic carbon source coating LiFe_(x)Mn_(1-x)PO_(4)suffers from the problem of non-uniform carbon cladding.Too thick carbon cladding layer instead hinders the de-embedding of lithium ions.In this paper,we choose cornstalk as the carbon source,then LiFe_(0.5)Mn_(0.5)PO_(4)@cornstalk-C(LFMP@C-C)with 3D anchoring structure is prepared by the solvothermal method.The results show that the LFMP with cornstalk as the carbon source has better performance compared to the sucrose-coated LFMP material(LFMP@C).The discharge capacity of LFMP@C-C is 116 mAh/g for the first cycle at 1 C and the capacity retention rate is 94.0%after 500 cycles,and the discharge capacity of LFMP@C-C is more than 17.17%higher than that of LFMP@C.