Mild polarization electric field in ultra-thin BN-Fe-graphene sandwich structure for efficient nitrogen reduction
The electrocatalytic N2 reduction reaction(NRR)is expected to supersede the traditional Ha-ber-Bosch technology for NH3 production under ambient conditions.The activity and selectivity of electrochemical NRR are restricted to a strong polarized electric field induced by the catalyst,cor-rect electron transfer direction,and electron tunneling distance between bare electrode and active sites.By coupling the chemical vapor deposition method with the poly(methyl methacyl-ate)-transfer method,an ultrathin sandwich catalyst,i.e.,Fe atoms(polarized electric field layer)sandwiched between ultrathin(within electron tunneling distance)BN(catalyst layer)and gra-phene film(conducting layer),is fabricated for electrocatalytic NRR.The sandwich catalyst not only controls the transfer of electrons to the BN surface in the correct direction under applied voltage but also suppresses hydrogen evolution reaction by constructing a neutral polarization electric field without metal exposure.The sandwich electrocatalyst NRR system achieve NH3 yield of 8.9 μg h-1 cm-2 and Faradaic Efficiency of 21.7％.The N2 adsorption,activation,and polarization electric field changes of three sandwich catalysts(BN-Fe-G,BN-Fe-BN,and G-Fe-G)during the electrocatalytic NRR are investigated by experiments and density functional theory simulations.Driven by applied voltage,the neutral polarized electric field induced by BN-Fe-G leads to the high activity of electro-catalytic NRR.
Ultra-thin BNFe dopingBN-Fe-grapheneMild polarization electric fieldNitrogen reduction reaction
万方数据
