Abstract
Developing earth-abundant electrocatalysts for hydrogen evolution reaction(HER)is important for the sustainable energy economy.Herein,efficient and stable heterocatalysts consisting of crystalline-amorphous M@MNx(M=Co,Fe,Ni)encapsulated in N-doped car-bon layers supported with N-doped graphene sheets(de-noted as M@MNx@NC-NG)are synthesized by facile hydrothermal reaction and nitridation process.During the nitriding process,metal ions in M(tzbc)2(H2O)4(tzbc=4-(1H-1,2,4-triazol-1-yl)benzoic acid)complexes are reduced to crystalline M cores,accompanied by the for-mation of amorphous MNx shells;the tzbc ligands are in-situ carbonized to form outermost N-doped carbon(NC)layers that connect with inner MNx via M-N-C motifs inherited from the complex precursors and inhibit the transition of MNx from amorphous to crystalline phase.The Co@CoNx@NC-NG catalyst exhibits excellent HER activity with small overpotentials of 45 and 64 mV at a cathode current density of 10 mA-cm-2 and low Tafel slopes of 40 and 85 mV·dec-1 in 0.5 mol-L-1 H2SO4 and 1.0 mol-L-1 KOH electrolytes,respectively.The Co@CoNx@NC-NG retains 97％of the initial overpoten-tial after 100,000 s in both acidic and alkaline media.Such outstanding HER performance originates from the crys-talline-amorphous Co@CoNx that redistributes electrons around the heterointerfaces,facilitating the conversion process of H+/H2O to hydrogen and thereby promoting HER kinetics.The outermost NC layers serve as the armor of Co@CoNx,and graphene nanosheets act as carriers of egg-like Co@CoNx@NC and conduction paths for electron shuttles,ensuring stable and continuous electrocatalytic hydrogen production.
基金项目
National Natural Science Foundation of China(91961201)
China Postdoctoral Science Foundation(2022M722344)
Shanxi"1331"Project()
NETL
NSTL
万方数据