BaFeO_(3-δ)-derived perovskites are promising cathodes for intermediate temperature solid oxide fuel cells.The activity of these perovskites depends on the number of oxygen vacancies in their lattice,which can be tun...BaFeO_(3-δ)-derived perovskites are promising cathodes for intermediate temperature solid oxide fuel cells.The activity of these perovskites depends on the number of oxygen vacancies in their lattice,which can be tuned by cationic substitution.Our first-principle calculations show that Ag is a promising substitute for the Fe site,resulting in a reduced oxygen vacancy formation energy compared with the pristine BaFeO_(3-δ).Ag has limited solubility in perovskites,and its introduction generates an Ag metal secondary phase,which influences the cathode performances.In this work,we investigate the matter,using a Ba0:9La0:1Fe_(1-x)AgxO_(3-δ)series of materials as a case study.Acknowledging the limited solubility of Ag in Ba0:9La0:1Fe_(1-x)AgxO_(3-δ),we aim to distinguish the effects of Ag substitution from those of the Ag secondary phase.We observed that Ag substitution increases the number of oxygen vacancies,confirming our calculations,and facilitates the oxygen incorporation.However,Ag substitution lowers the number of holes,in this way reducing the electronic p-type conductivity.On the other hand,Ag metal positively affects the electronic conductivity and helps the redistribution of the electronic charge at the cathode-electrolyte interface.展开更多
The deep burn skin injures usually severely damage the dermis with the loss of hair follicle loss,which are difficult to regenerate.Furthermore,severe burns often accompanied with large amount of wound exudates making...The deep burn skin injures usually severely damage the dermis with the loss of hair follicle loss,which are difficult to regenerate.Furthermore,severe burns often accompanied with large amount of wound exudates making the wound moist,easily infected,and difficult to heal.Therefore,it is of great clinical significance to develop wound dressings to remove wound exudates and promote hair follicle regeneration.In this study,a sandwich-structured wound dressing(SWD)with Janus membrane property was fabricated by hot compression molding using hydrophilic zinc silicate bioceramics(Hardystonite,ZnCS)and hydrophobic polylactic acid(PLA).This unique organic/inorganic Janus membrane structure revealed excellent exudate absorption property and effectively created a dry wound environment.Meanwhile,the incorporation of ZnCS bioceramic particles endowed the dressing with the bioactivity to promote hair follicle regeneration and wound healing through the release of Zn^(2+)and SiO^(2-)_(3)ions,and this bioactivity of the wound dressing is mainly attributed to the synergistic effect of Zn^(2+)and SiO^(2-)_(3)to promote the recruitment,viability,and differentiation of hair follicle cells.Our study demonstrates that the utilization of the Janus membrane and synergistic effect of different type bioactive ions are effective approaches for the design of wound dressings for burn wound healing.展开更多
基金The authors gratefully acknowledge the Research Grant Council of Hong Kong for support through the projects 16201820,and 16206019.
文摘BaFeO_(3-δ)-derived perovskites are promising cathodes for intermediate temperature solid oxide fuel cells.The activity of these perovskites depends on the number of oxygen vacancies in their lattice,which can be tuned by cationic substitution.Our first-principle calculations show that Ag is a promising substitute for the Fe site,resulting in a reduced oxygen vacancy formation energy compared with the pristine BaFeO_(3-δ).Ag has limited solubility in perovskites,and its introduction generates an Ag metal secondary phase,which influences the cathode performances.In this work,we investigate the matter,using a Ba0:9La0:1Fe_(1-x)AgxO_(3-δ)series of materials as a case study.Acknowledging the limited solubility of Ag in Ba0:9La0:1Fe_(1-x)AgxO_(3-δ),we aim to distinguish the effects of Ag substitution from those of the Ag secondary phase.We observed that Ag substitution increases the number of oxygen vacancies,confirming our calculations,and facilitates the oxygen incorporation.However,Ag substitution lowers the number of holes,in this way reducing the electronic p-type conductivity.On the other hand,Ag metal positively affects the electronic conductivity and helps the redistribution of the electronic charge at the cathode-electrolyte interface.
基金This work was supported by the National Key Research and Development Program of China(No.2016YFC1100201)the National Natural Science Foundation of China(No.81772078)+1 种基金the National Natural Science Foundation of China(No.81671830)the Science and Technology Commission of Shanghai Municipality(No.19441902300).
文摘The deep burn skin injures usually severely damage the dermis with the loss of hair follicle loss,which are difficult to regenerate.Furthermore,severe burns often accompanied with large amount of wound exudates making the wound moist,easily infected,and difficult to heal.Therefore,it is of great clinical significance to develop wound dressings to remove wound exudates and promote hair follicle regeneration.In this study,a sandwich-structured wound dressing(SWD)with Janus membrane property was fabricated by hot compression molding using hydrophilic zinc silicate bioceramics(Hardystonite,ZnCS)and hydrophobic polylactic acid(PLA).This unique organic/inorganic Janus membrane structure revealed excellent exudate absorption property and effectively created a dry wound environment.Meanwhile,the incorporation of ZnCS bioceramic particles endowed the dressing with the bioactivity to promote hair follicle regeneration and wound healing through the release of Zn^(2+)and SiO^(2-)_(3)ions,and this bioactivity of the wound dressing is mainly attributed to the synergistic effect of Zn^(2+)and SiO^(2-)_(3)to promote the recruitment,viability,and differentiation of hair follicle cells.Our study demonstrates that the utilization of the Janus membrane and synergistic effect of different type bioactive ions are effective approaches for the design of wound dressings for burn wound healing.
