Facile preparation and characterization of SmMn2O5/Mn2O3/g-C3N4 nanocomposites for electrochemical hydrogen storage application

Herein, a novel heterostructure of nano-SmMn2O5/Mn2O3 (SMM) coated on porous g-C3N4 (CN) nanosheets was developed via coupling strategy as potential "nano reservoir" in electrochemical hydrogen storage field. First, rational nanoscale interfacial engineering of binary SMM nanostructures was done by one-step auto-combustion method, in which amino acid types and the ratio of serine:Sm3+ cations are changed. Through structural and morphological evaluations, optimized samples having a molar ratio of Sm3+:serine = 1:4 exhibited mixed-phases of orthorhombic SmMn2O5 (89.9%) and cubic Mn2O3 (10.1%) structures as a ultrasmall particle network ranging from 22.03 to 94.70 nm. Additionally, assembling various amounts of SMM nanoarchitecture over CN nanosheets was controlled on electrochemical hydrogen storage features in 2.0 M KOH electrolyte. Impressively, loading 10% SMM to CN substrate depicted considerable discharge capacity of 1858.61 mAh g(-1) at 15th cycle at constant current of 1 mA, in which capacity value is 9.2 times more than that of sole SMM.