The biggest challenge of exploring the catalytic properties of under-coordinated nanoclusters is the issue of stability.We demonstrate herein that chemical dopants on sulfur-doped graphene(S-G)can be utilized to stabi...The biggest challenge of exploring the catalytic properties of under-coordinated nanoclusters is the issue of stability.We demonstrate herein that chemical dopants on sulfur-doped graphene(S-G)can be utilized to stabilize ultrafine(sub-2 nm)Au_(25)(PET)18 clusters to enable stable nitrogen reduction reaction(NRR)without significant structural degradation.The Au_(25)@S-G exhibits an ammonia yield rate of 27.5μgNH_(3)·mgAu^(-1)·h^(-1)at-0.5 V with faradic efficiency of 2.3%.More importantly,the anchored clusters preserve~80%NRR activity after four days of continuous operation,a significant improvement over the 15%remaining ammonia production rate for clusters loaded on undoped graphene tested under the same conditions.Isotope labeling experiments confirmed the ammonia was a direct reaction product of N2 feeding gas instead of other chemical contaminations.Ex-situ X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy of post-reaction catalysts reveal that the sulfur dopant plays a critical role in stabilizing the chemical state and coordination environment of Au atoms in clusters.Further ReaxFF molecular dynamics(RMD)simulation confirmed the strong interaction between Au nanoclusters(NCs)and S-G.This substrate-anchoring process could serve as an effective strategy to study ultrafine nanoclusters’electrocatalytic behavior while minimizing the destruction of the under-coordinated surface motif under harsh electrochemical reaction conditions.展开更多
基金This research was supported by the Director,Office of Science,Office of Basic Energy Sciences,Chemical Sciences,Geosciences,&Biosciences Division,of the US Department of Energy under Contract DEAC02-05CH11231,FWP CH030201(Catalysis Research Program)The Advanced Light Source was supported by the Director,Office of Science,Office of Basic Energy Sciences,of the US Department of Energy under Contract DE-AC02-05CH11231+1 种基金This work made use of the facilities at the NMR Facility,College of Chemistry,University of California,Berkeley.Inductively coupled plasma optical emission spectrometry was supported by the Microanalytical Facility,College of Chemistry,University of California,BerkeleyPart of this material(WAG,TC)was based on work performed by the Liquid Sunlight Alliance,which was supported by the US Department of Energy,Office of Science,Office of Basic Energy Sciences,Fuels from Sunlight Hub under Award Number DE-SC0021266.
文摘The biggest challenge of exploring the catalytic properties of under-coordinated nanoclusters is the issue of stability.We demonstrate herein that chemical dopants on sulfur-doped graphene(S-G)can be utilized to stabilize ultrafine(sub-2 nm)Au_(25)(PET)18 clusters to enable stable nitrogen reduction reaction(NRR)without significant structural degradation.The Au_(25)@S-G exhibits an ammonia yield rate of 27.5μgNH_(3)·mgAu^(-1)·h^(-1)at-0.5 V with faradic efficiency of 2.3%.More importantly,the anchored clusters preserve~80%NRR activity after four days of continuous operation,a significant improvement over the 15%remaining ammonia production rate for clusters loaded on undoped graphene tested under the same conditions.Isotope labeling experiments confirmed the ammonia was a direct reaction product of N2 feeding gas instead of other chemical contaminations.Ex-situ X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy of post-reaction catalysts reveal that the sulfur dopant plays a critical role in stabilizing the chemical state and coordination environment of Au atoms in clusters.Further ReaxFF molecular dynamics(RMD)simulation confirmed the strong interaction between Au nanoclusters(NCs)and S-G.This substrate-anchoring process could serve as an effective strategy to study ultrafine nanoclusters’electrocatalytic behavior while minimizing the destruction of the under-coordinated surface motif under harsh electrochemical reaction conditions.
