Today,nanocrystals enclosed by high-index facets(HIFs)are attracting widely attentions of researchers due to their tremendous potential in the field of catalysis,especially in electrocatalysis,such as electro-oxidatio...Today,nanocrystals enclosed by high-index facets(HIFs)are attracting widely attentions of researchers due to their tremendous potential in the field of catalysis,especially in electrocatalysis,such as electro-oxidation of small organic molecule(such as formic acid,methanol,and ethanol),oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),as well as the oxygen evolution reaction(OER).However,the practical applications of nanocrystals enclosed by HIFs still face many limitations in preparations of advanced electrocatalysts,including preparation strategy,limited life-time and stability.The development of advanced electrocatalysts enclosed with HIFs is crucial for solving these problems if the large-scale application of them is to be realized.Herein,we firstly detailedly demonstrate the identification methods of nanocrystals enclosed by HIFs,and then preparation strategies are elaborated in detail in this review.Current advanced nanocrystals enclosed by HIFs in electrocatalytic application are also summarized and we present representative achievements to further reveal the relationship of excellent electrocatalytic performance and nanocrystals with HIFs.Finally,we predict the remaining challenges and present our perspectives with regards of design strategies of improving electrocatalytic performance of Ptbased catalysts in the future.展开更多
在昆明西山国家森林公园地盘松林连续分布区内设置样地,并将样地内的地表凋落物分成枯枝、凋落物上层和凋落物下层3层,通过外业调查采集样品,在实验室测定载量、热值等相关燃烧能量参数,以单位面积热量为关键指标研究地盘松林地表凋落...在昆明西山国家森林公园地盘松林连续分布区内设置样地,并将样地内的地表凋落物分成枯枝、凋落物上层和凋落物下层3层,通过外业调查采集样品,在实验室测定载量、热值等相关燃烧能量参数,以单位面积热量为关键指标研究地盘松林地表凋落物的潜在能量。结果表明,在地盘松林地表凋落物中,凋落物上层、下层和枯枝的单位面积热量最大值差异不大,分别为51 866.3 k J/m2、48 942.13 k J/m2和42 611.53 k J/m2;平均值的差异也不大,分别为38 688.5 k J/m2、39 716.63 k J/m2和25 796.23 k J/m2。但最低值的差异却非常明显,凋落物上层的为25 510.8 k J/m2,枯枝的为8 980.93 k J/m2,凋落物下层的为30 491.1 k J/m2。展开更多
Designing the low cost, active, durable, and alcohol-tolerant cathode catalysts towards the oxygen reduction reaction(ORR) is significant for the large-scale commercialization of direct alcohol fuel cells.Recently, Pd...Designing the low cost, active, durable, and alcohol-tolerant cathode catalysts towards the oxygen reduction reaction(ORR) is significant for the large-scale commercialization of direct alcohol fuel cells.Recently, Pd-based nanocrystals have attracted attention as Pt-alternative cathode catalysts towards the ORR in the alkaline electrolyte. Unfortunately, the pristine Pd-based nanocrystals lack the selectivity towards the ORR due to their inherent activity for the alcohol molecule oxidation reaction in the alkaline electrolyte. In this work, polyethyleneimine(PEI) modified Au Pd alloy nanocrystals with Au-rich Au Pd alloy cores and Pd-rich Pd Au alloy shells(AuPd@PdAu-PEI) are successfully synthesized using a traditional chemical reduction method in presence of PEI. The rotating disk electrode(RDE) technique is applied to evaluate the ORR performance of AuPd@PdAu-PEI nanocrystals. Compared with commercial Pd black,AuPd@PdAu-PEI nanocrystals show significantly enhanced activity and durability towards the ORR, and simultaneously exhibit particular alcohol tolerance towards the ORR in the alkaline electrolyte.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22008135)the China Postdoctoral Science Foundation(No.2020M670345)。
文摘Today,nanocrystals enclosed by high-index facets(HIFs)are attracting widely attentions of researchers due to their tremendous potential in the field of catalysis,especially in electrocatalysis,such as electro-oxidation of small organic molecule(such as formic acid,methanol,and ethanol),oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),as well as the oxygen evolution reaction(OER).However,the practical applications of nanocrystals enclosed by HIFs still face many limitations in preparations of advanced electrocatalysts,including preparation strategy,limited life-time and stability.The development of advanced electrocatalysts enclosed with HIFs is crucial for solving these problems if the large-scale application of them is to be realized.Herein,we firstly detailedly demonstrate the identification methods of nanocrystals enclosed by HIFs,and then preparation strategies are elaborated in detail in this review.Current advanced nanocrystals enclosed by HIFs in electrocatalytic application are also summarized and we present representative achievements to further reveal the relationship of excellent electrocatalytic performance and nanocrystals with HIFs.Finally,we predict the remaining challenges and present our perspectives with regards of design strategies of improving electrocatalytic performance of Ptbased catalysts in the future.
文摘在昆明西山国家森林公园地盘松林连续分布区内设置样地,并将样地内的地表凋落物分成枯枝、凋落物上层和凋落物下层3层,通过外业调查采集样品,在实验室测定载量、热值等相关燃烧能量参数,以单位面积热量为关键指标研究地盘松林地表凋落物的潜在能量。结果表明,在地盘松林地表凋落物中,凋落物上层、下层和枯枝的单位面积热量最大值差异不大,分别为51 866.3 k J/m2、48 942.13 k J/m2和42 611.53 k J/m2;平均值的差异也不大,分别为38 688.5 k J/m2、39 716.63 k J/m2和25 796.23 k J/m2。但最低值的差异却非常明显,凋落物上层的为25 510.8 k J/m2,枯枝的为8 980.93 k J/m2,凋落物下层的为30 491.1 k J/m2。
基金sponsored by the National Natural Science Foundation of China(21473111)Fundamental Research Funds for the Central Universities(GK201602002 and GK201701007)
文摘Designing the low cost, active, durable, and alcohol-tolerant cathode catalysts towards the oxygen reduction reaction(ORR) is significant for the large-scale commercialization of direct alcohol fuel cells.Recently, Pd-based nanocrystals have attracted attention as Pt-alternative cathode catalysts towards the ORR in the alkaline electrolyte. Unfortunately, the pristine Pd-based nanocrystals lack the selectivity towards the ORR due to their inherent activity for the alcohol molecule oxidation reaction in the alkaline electrolyte. In this work, polyethyleneimine(PEI) modified Au Pd alloy nanocrystals with Au-rich Au Pd alloy cores and Pd-rich Pd Au alloy shells(AuPd@PdAu-PEI) are successfully synthesized using a traditional chemical reduction method in presence of PEI. The rotating disk electrode(RDE) technique is applied to evaluate the ORR performance of AuPd@PdAu-PEI nanocrystals. Compared with commercial Pd black,AuPd@PdAu-PEI nanocrystals show significantly enhanced activity and durability towards the ORR, and simultaneously exhibit particular alcohol tolerance towards the ORR in the alkaline electrolyte.
