The sluggish kinetics of the oxygen reduction reaction(ORR)and high over potential of oxygen evolution reaction(OER)are big challenges in the development of high-performance zinc-air batteries(ZABs)and fuel cells.In t...The sluggish kinetics of the oxygen reduction reaction(ORR)and high over potential of oxygen evolution reaction(OER)are big challenges in the development of high-performance zinc-air batteries(ZABs)and fuel cells.In this work,we report a rational design and a simple fabrication strategy of a photo-enhanced Co single-atom catalyst(SAC)comprising g-C3N4 coupled with cobalt-nitrogen-doped hierarchical mesoporous carbon(Co-N/MPC),forming a staggered p-n heterojunction that effectively improves charge separation and enhances electrocatalytic activity.The incorporation of Co SACs and g-C3N4 synergistically optimizes the photogenerated electron-hole pair separation,significantly boosting the intrinsic ORR-OER duplex activity.Under illumination,g-C_(3)N_(4)@Co-N/MPC exhibits an outstanding ORR half-wave potential(E1/2)of 0.841 V(vs.RHE)in 0.1 mol L^(–1)KOH and a low OER overpotential of 497.4 mV(vs.RHE)at 10 mA cm^(–2)in 1 mol L^(–1)KOH.Notably,the catalyst achieves an exceptional peak power density of 850.7 mW cm^(–2)in ZABs and of 411 mW cm^(–2)even in H_(2)-air fuel cell.In addition,g-C_(3)N_(4)@Co-N/MPC-based ZABs also show remarkable cycling stability exceeding 250 h.The advanced photo-induced charge separation at the p-n heterojunction facilitates faster electron transfer kinetics,and the mass transport owing to hierarchical mesoporous structure of Co-N-C,thereby reducing the overpotential and enhancing the overall energy conversion efficiency.This work provides a new perspective on designing next-generation of single-atom dispersed oxygen reaction catalysts,paving the way for high-performance photo-enhanced energy storage and conversion systems.展开更多
Developing highly efficient and recyclable photocatalysts has been regarded as an attractive strategy to solve antibiotic contaminants.Herein,we designed and fabricated Cy-C_(3) N_(4)/TiO_(2) S-scheme heterojunction f...Developing highly efficient and recyclable photocatalysts has been regarded as an attractive strategy to solve antibiotic contaminants.Herein,we designed and fabricated Cy-C_(3) N_(4)/TiO_(2) S-scheme heterojunction film with boosted charge transfer and a highly hydrophilic surface.The as-prepared heterojunction exhibited outstanding removal efficiency on tetracyclines and fluoroquinolone antibiotics(more than 80% within 90 min).The removal rate of 300-Cy-C_(3) N_(4)/TiO_(2) on norfloxacin(NOR)was 2.12,and 1.59 times higher than that of pristine TiO_(2),C_(3) N_(4)/TiO_(2),respectively.The excellent photocatalytic performance of 300-Cy-C_(3) N_(4)/TiO_(2) was attributed to the highly hydrophilic surface and effective transfer and separation of carriers.Moreover,the NOR degradation pathways were proposed based on the results of density functional theory(DFT),and liquid chromatography-mass spectrometry.The toxicity assessment indicated the toxicity of intermediates can be remarkably alleviated.The DFT calculation and selective photo-deposition experiment demonstrated that an internal electric field was formed at the heterojunction interface,and the charge carriers migrated between Cy-C_(3) N_(4) and TiO_(2) following an S-scheme transfer pathway.This research not only provides a promising method for tracking charge distribution on thin-film heterojunction photocatalysts but also helps us to design high-efficiency,and recyclable heterojunctions to solve antibiotic contaminants.展开更多
文摘The sluggish kinetics of the oxygen reduction reaction(ORR)and high over potential of oxygen evolution reaction(OER)are big challenges in the development of high-performance zinc-air batteries(ZABs)and fuel cells.In this work,we report a rational design and a simple fabrication strategy of a photo-enhanced Co single-atom catalyst(SAC)comprising g-C3N4 coupled with cobalt-nitrogen-doped hierarchical mesoporous carbon(Co-N/MPC),forming a staggered p-n heterojunction that effectively improves charge separation and enhances electrocatalytic activity.The incorporation of Co SACs and g-C3N4 synergistically optimizes the photogenerated electron-hole pair separation,significantly boosting the intrinsic ORR-OER duplex activity.Under illumination,g-C_(3)N_(4)@Co-N/MPC exhibits an outstanding ORR half-wave potential(E1/2)of 0.841 V(vs.RHE)in 0.1 mol L^(–1)KOH and a low OER overpotential of 497.4 mV(vs.RHE)at 10 mA cm^(–2)in 1 mol L^(–1)KOH.Notably,the catalyst achieves an exceptional peak power density of 850.7 mW cm^(–2)in ZABs and of 411 mW cm^(–2)even in H_(2)-air fuel cell.In addition,g-C_(3)N_(4)@Co-N/MPC-based ZABs also show remarkable cycling stability exceeding 250 h.The advanced photo-induced charge separation at the p-n heterojunction facilitates faster electron transfer kinetics,and the mass transport owing to hierarchical mesoporous structure of Co-N-C,thereby reducing the overpotential and enhancing the overall energy conversion efficiency.This work provides a new perspective on designing next-generation of single-atom dispersed oxygen reaction catalysts,paving the way for high-performance photo-enhanced energy storage and conversion systems.
基金funded by the National Natural Science Foundation of China(Nos.51772003 and 51701001)the Excellent Research and Innovation Team Project of Anhui Province(No.2023AH010077)the Key Research and Development Projects in Anhui Province(No.202004b11020021).
文摘Developing highly efficient and recyclable photocatalysts has been regarded as an attractive strategy to solve antibiotic contaminants.Herein,we designed and fabricated Cy-C_(3) N_(4)/TiO_(2) S-scheme heterojunction film with boosted charge transfer and a highly hydrophilic surface.The as-prepared heterojunction exhibited outstanding removal efficiency on tetracyclines and fluoroquinolone antibiotics(more than 80% within 90 min).The removal rate of 300-Cy-C_(3) N_(4)/TiO_(2) on norfloxacin(NOR)was 2.12,and 1.59 times higher than that of pristine TiO_(2),C_(3) N_(4)/TiO_(2),respectively.The excellent photocatalytic performance of 300-Cy-C_(3) N_(4)/TiO_(2) was attributed to the highly hydrophilic surface and effective transfer and separation of carriers.Moreover,the NOR degradation pathways were proposed based on the results of density functional theory(DFT),and liquid chromatography-mass spectrometry.The toxicity assessment indicated the toxicity of intermediates can be remarkably alleviated.The DFT calculation and selective photo-deposition experiment demonstrated that an internal electric field was formed at the heterojunction interface,and the charge carriers migrated between Cy-C_(3) N_(4) and TiO_(2) following an S-scheme transfer pathway.This research not only provides a promising method for tracking charge distribution on thin-film heterojunction photocatalysts but also helps us to design high-efficiency,and recyclable heterojunctions to solve antibiotic contaminants.
