A new methanol-tolerant oxygen reduction electrocatalyst,nitrogen-doped hollow carbon microspheres@platinum nanoparticles hybrids(HNCMS@PtNPs),has been synthesized by a facile template route.In brief,PtNPs were loaded...A new methanol-tolerant oxygen reduction electrocatalyst,nitrogen-doped hollow carbon microspheres@platinum nanoparticles hybrids(HNCMS@PtNPs),has been synthesized by a facile template route.In brief,PtNPs were loaded on the surface of NH2-functionalized SiO_(2)microspheres(PtNPs/SiO_(2)).Then,the PtNPs/SiO_(2)hybrids were wrapped by polydopamine(PDA)film.After direct carbonization of PDA-wrapped PtNPs/SiO_(2)hybrids under a nitrogen atmosphere and further treatment in a hydrofluoric acid solution,PtNPs embedded within nitrogen-doped hollow carbon microsphere(HNCMS)were obtained and labeled as HNCMS@PtNPs.Scanning electron microscopy,transmission electron microscopy,X-ray diffraction,Raman spectroscopy,specific surface area analysis,and X-ray photoelectron spectroscopy were used to characterize the HNCMS@PtNPs hybrids.The electrochemical properties of the HNCMS@PtNPs hybrids for oxygen reduction reaction have also been investigated by cyclic voltammetry and linear sweep voltammetry.The results show that the Pt loading mass in the HNCMS@PtNPs hybrids is up to 11.9%(w,mass fraction).Furthermore,the as-prepared HNCMS@PtNPs catalyst exhibits good electrocatalytic activity,high stability,and excellent methanol-tolerance toward oxygen reduction reactions,implying potential applications in practical direct methanol fuel cells(DMFCs)as methanol-tolerant cathodic catalysts.展开更多
Insufficient activity and instability(poisoning)of Pt-based electrocatalysts for methanol oxidation and oxygen reduction reactions(MOR/ORR)impede the development of direct methanol fuel cells.Here,CoWO_(4) nanoparticl...Insufficient activity and instability(poisoning)of Pt-based electrocatalysts for methanol oxidation and oxygen reduction reactions(MOR/ORR)impede the development of direct methanol fuel cells.Here,CoWO_(4) nanoparticles-loaded WO_(3) microrods coated by a thin carbon-layer are used as Pt-supports/co-catalysts for MOR/ORR.WO_(3) grows along the(110)crystal plane to form microrod(diameter of~0.6 um),which is coated by a carbon-layer(~5 nm).Pt-CoWO_(4)/WO_(3)@NCL-mr(850℃)shows a higher mass activity(2208 mA mg^(-1)_(pt))than the commercial Pt/C(659.4 mA mg^(-1)_(pt)).CoWO_(4)/WO_(3) heterojunction on the microrod surface with abundant oxygen vacancies allows the generation of surface-adsorbed hydroxyl to facilitate CO elimination and regeneration of the occupied Pt active-sites(promising stability).PtCo WO_(4)/WO_(3)@NCL-mr(850℃)has higher half-wave(0.46 V)and onset(0.54 V)potentials than Pt/C(0.41 and 0.50 V)for ORR.The microrod structure of Co WO_(4)/WO_(3)@NCL facilitates the dispersibility of Pt NPs to increase the utilization of Pt active sites and relieve the self-aggregation of Pt to obtain a promising synergy between Pt and CoWO_(4)(Co^(2+))for ORR in acid media.This study provides insights not only into the synthesis of acid-resistant WO_(3)@NCL microrod as active Pt co-catalyst,but also into the effective utilization of surface oxygen vacancies and Co^(2+) for MOR/ORR.展开更多
文摘A new methanol-tolerant oxygen reduction electrocatalyst,nitrogen-doped hollow carbon microspheres@platinum nanoparticles hybrids(HNCMS@PtNPs),has been synthesized by a facile template route.In brief,PtNPs were loaded on the surface of NH2-functionalized SiO_(2)microspheres(PtNPs/SiO_(2)).Then,the PtNPs/SiO_(2)hybrids were wrapped by polydopamine(PDA)film.After direct carbonization of PDA-wrapped PtNPs/SiO_(2)hybrids under a nitrogen atmosphere and further treatment in a hydrofluoric acid solution,PtNPs embedded within nitrogen-doped hollow carbon microsphere(HNCMS)were obtained and labeled as HNCMS@PtNPs.Scanning electron microscopy,transmission electron microscopy,X-ray diffraction,Raman spectroscopy,specific surface area analysis,and X-ray photoelectron spectroscopy were used to characterize the HNCMS@PtNPs hybrids.The electrochemical properties of the HNCMS@PtNPs hybrids for oxygen reduction reaction have also been investigated by cyclic voltammetry and linear sweep voltammetry.The results show that the Pt loading mass in the HNCMS@PtNPs hybrids is up to 11.9%(w,mass fraction).Furthermore,the as-prepared HNCMS@PtNPs catalyst exhibits good electrocatalytic activity,high stability,and excellent methanol-tolerance toward oxygen reduction reactions,implying potential applications in practical direct methanol fuel cells(DMFCs)as methanol-tolerant cathodic catalysts.
基金the support by National Natural Science Foundation of China (52070074, 21806031 and 51578218)Long Jiang Scholars Program (Young Scholar, Q201912)。
文摘Insufficient activity and instability(poisoning)of Pt-based electrocatalysts for methanol oxidation and oxygen reduction reactions(MOR/ORR)impede the development of direct methanol fuel cells.Here,CoWO_(4) nanoparticles-loaded WO_(3) microrods coated by a thin carbon-layer are used as Pt-supports/co-catalysts for MOR/ORR.WO_(3) grows along the(110)crystal plane to form microrod(diameter of~0.6 um),which is coated by a carbon-layer(~5 nm).Pt-CoWO_(4)/WO_(3)@NCL-mr(850℃)shows a higher mass activity(2208 mA mg^(-1)_(pt))than the commercial Pt/C(659.4 mA mg^(-1)_(pt)).CoWO_(4)/WO_(3) heterojunction on the microrod surface with abundant oxygen vacancies allows the generation of surface-adsorbed hydroxyl to facilitate CO elimination and regeneration of the occupied Pt active-sites(promising stability).PtCo WO_(4)/WO_(3)@NCL-mr(850℃)has higher half-wave(0.46 V)and onset(0.54 V)potentials than Pt/C(0.41 and 0.50 V)for ORR.The microrod structure of Co WO_(4)/WO_(3)@NCL facilitates the dispersibility of Pt NPs to increase the utilization of Pt active sites and relieve the self-aggregation of Pt to obtain a promising synergy between Pt and CoWO_(4)(Co^(2+))for ORR in acid media.This study provides insights not only into the synthesis of acid-resistant WO_(3)@NCL microrod as active Pt co-catalyst,but also into the effective utilization of surface oxygen vacancies and Co^(2+) for MOR/ORR.
