A novel nanosized amorphous Ru-Fe-B/ZrO2 alloy catalyst for benzene selective hydrogenation to cyclohexene was investigated. The superior properties of this catalyst were attributed to the combination of the nanosize ...A novel nanosized amorphous Ru-Fe-B/ZrO2 alloy catalyst for benzene selective hydrogenation to cyclohexene was investigated. The superior properties of this catalyst were attributed to the combination of the nanosize and the amorphous character as well as to its textural character. In addition, the concentration of zinc ions, the content of ZrO2 in the slurry, and the pretreatment of the catalyst were found to be effective in improving the activity and the selectivity of the catalyst.展开更多
Fe-N-C catalysts are promising substitutes for precious-metal platinum in acidic oxygen reduction reactions(ORR),yet their moderate intrinsic activity and susceptibility to reactive oxygen species(ROS)-induced degrada...Fe-N-C catalysts are promising substitutes for precious-metal platinum in acidic oxygen reduction reactions(ORR),yet their moderate intrinsic activity and susceptibility to reactive oxygen species(ROS)-induced degradation hinder practical implementation.Herein,we fabricate a Ru-Fe dual-site catalyst(RuFe-N-C)through a two-step pyrolysis strategy.Structural characterization reveals atomic-scale proximity between Ru single atoms and Fe-N_(4) moieties,exhibiting a projected distance of~1.7Å.This configuration induces Fe–N bond elongation accompanied by 2.5%lattice distortion.The optimized RuFe-N-C catalyst exhibits high ORR performance,with a half-wave potential(E_(1/2))of 0.840 V and peak power density(P_(max))of 938 mW cm^(-2) under 150 kPa absolute H_(2)-O_(2).These metrics signify substantial enhancements relative to conventional Fe-N-C benchmarks(+21 mV in E_(1/2) and+42%in P_(max)).Moreover,the catalyst maintains outstanding stability,showing merely 17 mV E_(1/2) decay after 10000 accelerated durability test(ADT)cycles.Experimental analyses reveal a bifunctional mechanism:(1)Adjacent Ru sites substantially enhance the intrinsic ORR activity of Fe-N_(4) moieties,delivering a notable turnover frequency(TOF=17.86 e site^(-1) s^(-1) at 0.85 V vs.RHE)that exceeds state-of-the-art Fe-N-C benchmarks by 1-2 orders of magnitude(<1 e site^(-1) s^(-1));(2)Ru centers function as electron relays that facilitate ROS scavenging,thus suppressing degradation.This work establishes a paradigm for engineering bimetallic single-atom catalysts through synergistic electronic modulation to concurrently enhance activity and stability.展开更多
文摘A novel nanosized amorphous Ru-Fe-B/ZrO2 alloy catalyst for benzene selective hydrogenation to cyclohexene was investigated. The superior properties of this catalyst were attributed to the combination of the nanosize and the amorphous character as well as to its textural character. In addition, the concentration of zinc ions, the content of ZrO2 in the slurry, and the pretreatment of the catalyst were found to be effective in improving the activity and the selectivity of the catalyst.
文摘Fe-N-C catalysts are promising substitutes for precious-metal platinum in acidic oxygen reduction reactions(ORR),yet their moderate intrinsic activity and susceptibility to reactive oxygen species(ROS)-induced degradation hinder practical implementation.Herein,we fabricate a Ru-Fe dual-site catalyst(RuFe-N-C)through a two-step pyrolysis strategy.Structural characterization reveals atomic-scale proximity between Ru single atoms and Fe-N_(4) moieties,exhibiting a projected distance of~1.7Å.This configuration induces Fe–N bond elongation accompanied by 2.5%lattice distortion.The optimized RuFe-N-C catalyst exhibits high ORR performance,with a half-wave potential(E_(1/2))of 0.840 V and peak power density(P_(max))of 938 mW cm^(-2) under 150 kPa absolute H_(2)-O_(2).These metrics signify substantial enhancements relative to conventional Fe-N-C benchmarks(+21 mV in E_(1/2) and+42%in P_(max)).Moreover,the catalyst maintains outstanding stability,showing merely 17 mV E_(1/2) decay after 10000 accelerated durability test(ADT)cycles.Experimental analyses reveal a bifunctional mechanism:(1)Adjacent Ru sites substantially enhance the intrinsic ORR activity of Fe-N_(4) moieties,delivering a notable turnover frequency(TOF=17.86 e site^(-1) s^(-1) at 0.85 V vs.RHE)that exceeds state-of-the-art Fe-N-C benchmarks by 1-2 orders of magnitude(<1 e site^(-1) s^(-1));(2)Ru centers function as electron relays that facilitate ROS scavenging,thus suppressing degradation.This work establishes a paradigm for engineering bimetallic single-atom catalysts through synergistic electronic modulation to concurrently enhance activity and stability.
