Nasir Salisu, Hussein Mohd Zobir, Yusof Nor Azah, Zainal Zulkarnain
Materials Synthesis and Characterisation Laboratory (MSCL), Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia.
Department of Chemistry, Faculty of Science, Federal University Dutse, 7156 Dutse, Jigawa State, Nigeria.
Nanomaterials (Basel). 2017 Jul 13;7(7):182. doi: 10.3390/nano7070182.
Herein, a new approach was proposed to produce reduced graphene oxide (rGO) from graphene oxide (GO) using various oil palm wastes: oil palm leaves (OPL), palm kernel shells (PKS) and empty fruit bunches (EFB). The effect of heating temperature on the formation of graphitic carbon and the yield was examined prior to the GO and rGO synthesis. Carbonization of the starting materials was conducted in a furnace under nitrogen gas for 3 h at temperatures ranging from 400 to 900 °C and a constant heating rate of 10 °C/min. The GO was further synthesized from the as-carbonized materials using the 'improved synthesis of graphene oxide' method. Subsequently, the GO was reduced by low-temperature annealing reduction at 300 °C in a furnace under nitrogen gas for 1 h. The I/I ratio calculated from the Raman study increases with the increasing of the degree of the graphitization in the order of rGO from oil palm leaves (rGOOPL) < rGO palm kernel shells (rGOPKS) < rGO commercial graphite (rGOCG) < rGO empty fruit bunches (rGOEFB) with the I/I values of 1.06, 1.14, 1.16 and 1.20, respectively. The surface area and pore volume analyses of the as-prepared materials were performed using the Brunauer Emmett Teller-Nitrogen (BET-N₂) adsorption-desorption isotherms method. The lower BET surface area of 8 and 15 m g observed for rGOCG and rGOOPL, respectively could be due to partial restacking of GO layers and locally-blocked pores. Relatively, this lower BET surface area is inconsequential when compared to rGOPKS and rGOEFB, which have a surface area of 114 and 117 m² g, respectively.
在此，提出了一种利用各种油棕废弃物：油棕叶（OPL）、棕榈壳（PKS）和空果串（EFB）从氧化石墨烯（GO）制备还原氧化石墨烯（rGO）的新方法。在合成GO和rGO之前，研究了加热温度对石墨化碳形成和产率的影响。起始材料在氮气气氛下于炉中在400至900℃的温度范围内以10℃/min的恒定加热速率碳化3小时。使用“改进的氧化石墨烯合成”方法从碳化后的材料中进一步合成GO。随后，在氮气气氛下于炉中300℃低温退火还原1小时将GO还原。根据拉曼研究计算的I/I比随着石墨化程度的增加而增加，顺序为油棕叶rGO（rGOOPL）<棕榈壳rGO（rGOPKS）<商业石墨rGO（rGOCG）<空果串rGO（rGOEFB），其I/I值分别为1.06、1.14、1.16和1.20。使用布鲁诺尔-埃米特-泰勒氮气（BET-N₂）吸附-脱附等温线方法对所制备材料进行表面积和孔体积分析。rGOCG和rGOOPL观察到的较低BET表面积分别为8和15 m²/g，这可能是由于GO层的部分重新堆叠和局部堵塞的孔。相对而言，与表面积分别为114和117 m²/g的rGOPKS和rGOEFB相比，这种较低的BET表面积影响不大。
