Highly efficient electrocatalysts derived from carbon black supported non-precious metal macrocycle catalysts for oxygen reduction reaction

For the sake of accelerating the commercial application of fuel cells, non-noble metal catalysts with high activity and high stability have been widely developed to replace platinum-based catalysts. Here, we report a simple but cost-effective synthetic strategy using iron tetra-amino phthalocyanine(FePC-NH_2)and modified carbon black(HCB) to obtain a novel oxygen reduction electrocatalyst(named as FePCNH_2/HCB-800) with Fe_2O_3 wrapped in nitrogen-doped carbon(N-carbon) as active site. The HCB as template can effectively promotes the formation of Fe_2O_3 active site in the catalysts. Compared to commercial Pt/C catalyst, the Fe PC-NH_2/HCB-800 catalyst exhibits high electrocatalytic activity for oxygen reduction reaction(ORR) with onset potential of 0.98 V and half-wave potential with 0.84 V vs. reversible hydrogen electrode(RHE). Meanwhile, the catalyst also shows excellent circulation stability. We believe that this work provides a platform for ORR and is conducive to the commercialization of fuel cells and metal-air batteries.

早产儿出生后早期屈光状态及其影响因素

目的:探讨早产儿矫正胎龄32~40周的屈光状态,评估早产儿屈光发育与出生体质量、出生孕龄以及早产儿视网膜病变(ROP)的相关性。方法:选取2016年3-12月在浙江大学医学院附属妇产科医院NICU及温州医科大学附属眼视光医院杭州院区接受ROP筛查的早产儿为研究对象,对早产儿屈光状态以及相关影响因素进行前瞻性研究。在矫正胎龄32~40周时右眼行睫状肌麻痹下检影验光,再进行ROP筛查并记录。记录早产儿的基本信息如出生体质量、出生孕龄、性别、吸氧史等以及接受检查时的矫正胎龄并进行统计分析。采用Pearson相关性分析来研究等效球镜度(SE)分别与出生体质量、出生孕龄、矫正胎龄之间的关系。采用独立样本t检验来比较矫正胎龄40周时有无ROP的SE差异。结果:共333例早产儿纳入研究,其中男175例,女158例。收集屈光记录542份。早产儿出生孕龄为26~36(31.3±2.1)周,出生体质量为740~3 390(1 643±418)g。SE随着早产儿矫正胎龄的增大而增大(r=0.455,P<0.001)。早产儿出生后4~5周,出生孕龄(r=0.373,P<0.001)、出生体质量(r=0.345,P<0.001)均和SE呈正相关。至早产儿矫正胎龄40周时,SE与出生体质量呈正相关(r=0.197,P=0.021),与出生孕龄无相关性,合并ROP的早产儿相比没有ROP的有较低的SE(t=2.225,P=0.028)。结论:早产儿在出生后早期矫正胎龄32~40周时,屈光状态向远视发展。在出生后4~5周,出生孕龄小或出生体质量低的早产儿更偏向于近视状态。至矫正胎龄40周时,有ROP或者低出生体质量的早产儿有较低的SE,而与出生孕龄无相关性。