Nickel-based layered double hydroxides(LDHs)are widely recognized as promising substitutes for noble metal catalysts in the oxygen evolution reaction(OER).However,conventional Ni^(2+)sites exhibit a high-spin configur...Nickel-based layered double hydroxides(LDHs)are widely recognized as promising substitutes for noble metal catalysts in the oxygen evolution reaction(OER).However,conventional Ni^(2+)sites exhibit a high-spin configuration(d_(xz)^(2)d_(yz)^(2)d_(xy)^(2)d_(x^(2)-y^(2))^(1)d_(z^(2))^(1))with excessive frontier-orbital occupancy,resulting in weak binding strength toward oxygen intermediates,which dramatically limits their OER performance.Herein,we first report the successful construction of low-spin state Ni^(2+)(d_(xz)^(2)d_(yz)^(2)d_(xy)^(2)d_(x^(2)-y^(2))^(1)d_(z^(2))^(0))in NiCoFe-LDH(LS-NCF)through oxygen defect engineering.LS-NCF exhibits a splendid OER activity with an ultralow overpotential of 241 mV at the current density of 1 A·cm^(−2),which is 79 mV lower than that of the conventional NiCoFe-LDH d_(z^(2)) with high-spin Ni^(2+)(HS-NCF),significantly outperforming previously reported transition metal-based catalysts.Comprehensive studies reveal that LS Ni^(2+)with reduced orbital occupancy effectively enhances oxygen intermediates adsorption through reinforcing the orbital hybridization between Ni 3d and O 2p.Moreover,the d-band center of LS Ni^(2+)is closer to the Fermi level compared to that of HS Ni^(2+),thus accelerating electron transfer.Consequently,the strengthened adsorption of ^(*)O intermediate and accelerated electron transfer in LS-NCF efficiently lower the reaction energy barrier of the rate-determining step(^(*)O→^(*)OOH),thereby greatly boosting its OER performance.This work provides valuable insights into designing high-performance Ni-based electrocatalysts via spintronic-level engineering.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22379023 and 22102007)the China Postdoctoral Science Foundation(No.2023M740555)+3 种基金Heilongjiang Provincial Postdoctoral Science Foundation(No.LBH-Z23001)Heilongjiang Provincial Natural Science Foundation Outstanding Youth Fund Project(No.YQ2024B002)the Foundation of State Key Laboratory of Catalysis(No.N-22-07)the Fundamental Research Funds for the Central Universities(No.2572023CT10).
文摘Nickel-based layered double hydroxides(LDHs)are widely recognized as promising substitutes for noble metal catalysts in the oxygen evolution reaction(OER).However,conventional Ni^(2+)sites exhibit a high-spin configuration(d_(xz)^(2)d_(yz)^(2)d_(xy)^(2)d_(x^(2)-y^(2))^(1)d_(z^(2))^(1))with excessive frontier-orbital occupancy,resulting in weak binding strength toward oxygen intermediates,which dramatically limits their OER performance.Herein,we first report the successful construction of low-spin state Ni^(2+)(d_(xz)^(2)d_(yz)^(2)d_(xy)^(2)d_(x^(2)-y^(2))^(1)d_(z^(2))^(0))in NiCoFe-LDH(LS-NCF)through oxygen defect engineering.LS-NCF exhibits a splendid OER activity with an ultralow overpotential of 241 mV at the current density of 1 A·cm^(−2),which is 79 mV lower than that of the conventional NiCoFe-LDH d_(z^(2)) with high-spin Ni^(2+)(HS-NCF),significantly outperforming previously reported transition metal-based catalysts.Comprehensive studies reveal that LS Ni^(2+)with reduced orbital occupancy effectively enhances oxygen intermediates adsorption through reinforcing the orbital hybridization between Ni 3d and O 2p.Moreover,the d-band center of LS Ni^(2+)is closer to the Fermi level compared to that of HS Ni^(2+),thus accelerating electron transfer.Consequently,the strengthened adsorption of ^(*)O intermediate and accelerated electron transfer in LS-NCF efficiently lower the reaction energy barrier of the rate-determining step(^(*)O→^(*)OOH),thereby greatly boosting its OER performance.This work provides valuable insights into designing high-performance Ni-based electrocatalysts via spintronic-level engineering.
