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Graphene supported NiO/Ni nanoparticles as efficient photocatalyst for gas phase CO2 reduction with hydrogen
Applied Catalysis B: Environment and Energy ( IF 20.2 ) Pub Date : 2017-10-31 , DOI: 10.1016/j.apcatb.2017.10.071
Diego Mateo , Josep Albero , Hermenegildo García

The photocatalytic activity of NiO/Ni nanoparticles (NPs) supported on defective graphene (NiO/Ni-G) has been tested for the photoassisted CO2 reduction with H2. NiO/Ni-G was prepared by H2 reduction of NiCl2 adsorbed on few-layers defective G and storage under air. An optimal Ni loading of 23 wt% was found, reaching the maximum specific CH4 formation rate (642 μmol CH4 gNi−1 h−1 at 200 °C) and quantum yield of 1.98%. Under the same conditions Ni NPs supported on silica-alumina or NiO NPs exhibit notably lower specific CH4 production rates than NiO/Ni-G. It was found that H2O formed in the reaction has a detrimental influence on the photocatalytic activity and evidence supports that H2O desorption is one of the reasons why the system requires heating. Under continuous flow operation, undesirable water molecules were easier desorbed from the NiO/Ni-G photocatalyst than in the batch mode, reaching a steady specific CH4 production rate of 244.8 μL h−1 for 50 mg of NiO/Ni-G catalyst with a residence time of 3.1 s. Quenching experiments with electron donor of different oxidation potential (dimethylaniline, anisole and p-xylene) are compatible with a mechanism involving photoinduced charge separation.



中文翻译:

石墨烯负载的NiO / Ni纳米颗粒作为氢气有效还原气相CO 2的有效光催化剂

测试了负载在有缺陷的石墨烯上的NiO / Ni纳米颗粒(NPs)的光催化活性(NiO / Ni-G)对H 2进行的光辅助CO 2还原。通过H 2还原吸附在几层缺陷G上的NiCl 2并在空气中存储来制备NiO / Ni-G 。发现最佳的Ni负载量为23wt%,达到最大的比CH 4形成速率(200℃下642μmolCH 4  g Ni -1  h -1)和量子产率为1.98%。在相同条件下,负载在二氧化硅-氧化铝上的Ni NP或NiO NP的CH 4生成速率明显低于NiO / Ni-G。发现H 2反应中形成的O对光催化活性有不利影响,证据支持H 2 O的解吸是系统需要加热的原因之一。在连续流动操作下,与分批模式相比,不良的水分子更容易从NiO / Ni-G光催化剂中解吸,对于50 mg NiO / Ni-G催化剂,稳定的CH 4特定比CH 4生产率为244.8μLh -1。停留时间为3.1 s。用具有不同氧化电位的电子给体(二甲基苯胺,苯甲醚和对二甲苯)进行的猝灭实验与涉及光致电荷分离的机理兼容。

更新日期:2017-10-31
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