Single-metal sites anchored in nitrogen-doped nanocarbons are recognized as potent electrocatalysts for applications in energy conversion and storage.Here,an innovative inorganic salt-mediated secondary calcination st...Single-metal sites anchored in nitrogen-doped nanocarbons are recognized as potent electrocatalysts for applications in energy conversion and storage.Here,an innovative inorganic salt-mediated secondary calcination strategy was developed to construct robust Pt single-atom catalysts on nitrogen-and oxygen-doped graphene nanosheets(Pt-N/O-GNs),thereby significantly enhancing the efficiency of the electrocatalytic oxygen reduction reaction(ORR).The ultrathin N/O-GNs,obtained by stripping Zn-ZIF with auxiliaries of KCl and LiCl,provide stable anchoring sites for highly exposed Pt-N_(3)O active structures.The Pt-N/O-GNs catalyst,featuring a low Pt loading of 0.44 wt%,demonstrates exceptional mass activity in the ORR process.It attains an impressive onset potential of 0.99 V and a half-wave potential of 0.88 V.The zinc-air battery driven by the Pt-N/O-GNs displays superior power density and cycle stability.Theoretical computational studies reveal that the structure of heteroatoms doped in few-layer graphene facilitates the stable anchoring of single-atom configurations.The findings provide new perspectives for the tailored design and fabrication of single-metal-site electrocatalysts.展开更多
The efficient conversion of lignin into mono-cycloalkanes via both C–O and C–C bonds cleavage are attractive,but challenging due to the high C–C bond dissociation energy.Previous studies have demonstrated that NbO_...The efficient conversion of lignin into mono-cycloalkanes via both C–O and C–C bonds cleavage are attractive,but challenging due to the high C–C bond dissociation energy.Previous studies have demonstrated that NbO_(x)-based catalysts exhibited exceptional capabilities for C_(Ar)–C bond cleavage and broken the limitation of lignin monomers.In this work,we presented an economical multifunctional Pt-Nb/MOR catalyst that achieved an impressive monomer yield of 147%during the depolymerization and hydrodeoxygenation of lignin into mono-cycloalkanes.Reaction pathway studies showed that unlike traditional NbO_(x)-based catalytic system,bicyclohexane was an important intermediate in this system and followed the C_(sp3)–C_(sp3)cleavage pathway after complete cyclic-hydrogenation.Deep investigations demonstrated that the doping of Nb in Pt/MOR not only enhanced the activation of hydrogen by Pt,but also increased the acidity of MOR,both of these are favor for the hydrogenolytic cleavage of C_(sp3)–C_(sp3)bonds.This work provides a low-cost catalyst to obtain high-yield monomers from lignin under relatively mild conditions and would help to design catalysts with higher activity for the valorization of lignin.展开更多
文摘Single-metal sites anchored in nitrogen-doped nanocarbons are recognized as potent electrocatalysts for applications in energy conversion and storage.Here,an innovative inorganic salt-mediated secondary calcination strategy was developed to construct robust Pt single-atom catalysts on nitrogen-and oxygen-doped graphene nanosheets(Pt-N/O-GNs),thereby significantly enhancing the efficiency of the electrocatalytic oxygen reduction reaction(ORR).The ultrathin N/O-GNs,obtained by stripping Zn-ZIF with auxiliaries of KCl and LiCl,provide stable anchoring sites for highly exposed Pt-N_(3)O active structures.The Pt-N/O-GNs catalyst,featuring a low Pt loading of 0.44 wt%,demonstrates exceptional mass activity in the ORR process.It attains an impressive onset potential of 0.99 V and a half-wave potential of 0.88 V.The zinc-air battery driven by the Pt-N/O-GNs displays superior power density and cycle stability.Theoretical computational studies reveal that the structure of heteroatoms doped in few-layer graphene facilitates the stable anchoring of single-atom configurations.The findings provide new perspectives for the tailored design and fabrication of single-metal-site electrocatalysts.
文摘The efficient conversion of lignin into mono-cycloalkanes via both C–O and C–C bonds cleavage are attractive,but challenging due to the high C–C bond dissociation energy.Previous studies have demonstrated that NbO_(x)-based catalysts exhibited exceptional capabilities for C_(Ar)–C bond cleavage and broken the limitation of lignin monomers.In this work,we presented an economical multifunctional Pt-Nb/MOR catalyst that achieved an impressive monomer yield of 147%during the depolymerization and hydrodeoxygenation of lignin into mono-cycloalkanes.Reaction pathway studies showed that unlike traditional NbO_(x)-based catalytic system,bicyclohexane was an important intermediate in this system and followed the C_(sp3)–C_(sp3)cleavage pathway after complete cyclic-hydrogenation.Deep investigations demonstrated that the doping of Nb in Pt/MOR not only enhanced the activation of hydrogen by Pt,but also increased the acidity of MOR,both of these are favor for the hydrogenolytic cleavage of C_(sp3)–C_(sp3)bonds.This work provides a low-cost catalyst to obtain high-yield monomers from lignin under relatively mild conditions and would help to design catalysts with higher activity for the valorization of lignin.
