Enhanced H2 production from hydrolysis of sodium borohydride using Co3O4 nanoparticles assembled coatings prepared by pulsed laser deposition
Enhanced H2 production from hydrolysis of sodium borohydride using Co3O4 nanoparticles assembled coatings prepared by pulsed laser deposition
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DOI：
10.1016/j.apcata.2016.01.031
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发表时间：
2016-04-10
影响因子：
5.5
通讯作者：
Miotello, A.
中科院分区：
文献类型：
--
作者：
Edla, R.;Gupta, S.;Miotello, A.
采用脉冲激光沉积(PLD)技术，在优化的工艺参数下，制备了纳米Co3O4纳米粒子组装涂层(NPAC)催化剂。在高激光强度下发生的相爆炸现象产生了平均尺寸接近5 nm的纳米粒子，其尺寸分布窄(3-10 nm)，团聚程度低，以涂层的形式随机排列在衬底表面。与化学合成的Co3O4晶体粉末相比，PLD法制备的NPAC对NaBH4水解生成H-2的催化活性显著提高。NPAC的最大产氢速率(5010mlmin(-1)g(CAT)(-1))约为Co3O4粉末(1000mlmin(-1)g(CAT)-1)的5倍，这主要是由于Co3O4纳米粒子的大小和形状决定了涂层具有较高的比表面积和大量的活性中心。通过改变PLD过程中的氧分压，在NPAC中形成了Co3O4和CoO两种不同的氧化钴相，发现Co3O4相比CoO相具有更高的催化活性和更低的氧化数。通过改变激光强度和衬底温度来调节纳米Co3O4的形貌和结晶度，并研究了它们对氢气生成速率的影响。结果表明，纳米颗粒表面具有非晶态和纳米晶混合相，是相互作用和NaBH4转化的活性中心。(C)2016年，由爱思唯尔出版。
Nanocatalysts, in the form of nanoparticles assembled coatings (NPACs) of Co3O4, were synthesized by pulsed laser deposition (PLD) with optimized parameters. Phase explosion phenomena occurring at high laser fluences produce nanoparticles (NPs) with an average size of similar to 5 nm having narrow size distribution (3-10 nm) and low degree of agglomeration, which are randomly arranged in the form of coating on the substrate surface. In comparison with chemically synthesized Co3O4 crystalline powder, the NPACs deposited by PLD showed significantly higher catalytic activity for H-2 generation by hydrolysis of NaBH4. Maximum H-2 generation rate obtained by NPACs (5010 ml min(-1) g(cat)(-1)) is about 5 times higher than that produced by Co3O4 powder (1000 ml min(-1) g(cat)(-1)), which is mainly attributed to high surface area and large number of active sites provided by the Co3O4 NPs in the coating owing to their size and shape. By varying the O-2 pressure during PLD, two different cobalt oxide phases, namely Co3O4 and CoO, were formed in NPACs and found that Co3O4 phase is more active for hydrolysis than CoO phase with lower oxidation number. The morphology and crystallinity of Co3O4 NPACs were tuned by varying the laser fluence and substrate temperature respectively, and their effect on H-2 generation rate was studied. The results showed that the NPs with mixed amorphous-nanocrystalline phase on the surface act as active sites for favorable interaction and NaBH4 conversion. (C) 2016 Published by Elsevier B.V.