To date, studies pertaining the usage of aliphatic dicarboxylic acids (DCAs) in the preparation of graphene-based hydrogels are limited and mainly has been applied either as a reducing agent or cross-linkers. The modification of the hydrogels' properties can be achieved via the introduction of small amount of additive into the starting material, graphene oxide (GO). The facile synthetic protocol enables the impartation of desired properties to the graphene-based hydrogel as intended for their specific applications. In this study, the in-situ preparation of reduced graphene hydrogel (rGH) was carried out in the presence of a series of aliphatic DCAs namely oxalic acid (OA), malonic acid (MA), succinic acid (SA), glutaric acid (GA) and adipic acid (AA) in the GO reaction mixture via green hydrothermal method and freeze-drying. The as-prepared hydrogels were systematically characterized to probe the changes in their chemical and physical changes. Higher specific surface (SSA) of the hydrogel is obtained for shorter chain length DCAs. The FTIR and XPS results also indicated that shorter chain DCAs exhibited better reducing capability in the removal of oxygen functional groups. The C/O ratio obtained showed decrement with the increase in the chain length of the DCA. On the other hand, good dispersity was found for longer chain DCAs in polar solvent. Overall, this study should provide a comprehensive understanding on hydrothermally reduced graphene hydrogels prepared in the presence of dicarboxylic acids.

迄今为止，关于在制备基于石墨烯的水凝胶中使用脂族二羧酸（DCA）的研究是有限的，并且主要已被用作还原剂或交联剂。可以通过将少量添加剂引入起始材料氧化石墨烯（GO）中来实现水凝胶性能的改变。简便的合成方案能够为基于石墨烯的水凝胶赋予特定用途所需的特性。在这项研究中，还原石墨烯水凝胶（rGH）的原位制备是在一系列脂肪族DCA（草酸（OA），丙二酸（MA），琥珀酸（SA），戊二酸（ GA）和己二酸（AA）在GO反应混合物中通过绿色水热法进行冷冻干燥。对所制备的水凝胶进行了系统表征，以探究其化学和物理变化的变化。对于较短链长的DCA，可获得较高的水凝胶比表面积（SSA）。FTIR和XPS结果还表明，较短链的DCA在去除氧官能团方面表现出更好的还原能力。所获得的C / O比随DCA链长的增加而降低。另一方面，发现较长链的DCA在极性溶剂中具有良好的分散性。总体而言，这项研究应提供对在二羧酸存在下制备的水热还原石墨烯水凝胶的全面理解。对于较短链长的DCA，可获得较高的水凝胶比表面积（SSA）。FTIR和XPS结果还表明，较短链的DCA在去除氧官能团方面表现出更好的还原能力。所获得的C / O比随DCA链长的增加而降低。另一方面，发现较长链的DCA在极性溶剂中具有良好的分散性。总体而言，这项研究应提供对在二羧酸存在下制备的水热还原石墨烯水凝胶的全面理解。对于较短链长的DCA，可获得较高的水凝胶比表面积（SSA）。FTIR和XPS结果还表明，较短链的DCA在去除氧官能团方面表现出更好的还原能力。所获得的C / O比随DCA链长的增加而降低。另一方面，发现较长链的DCA在极性溶剂中具有良好的分散性。总体而言，这项研究应提供对在二羧酸存在下制备的水热还原石墨烯水凝胶的全面理解。发现长链DCA在极性溶剂中具有良好的分散性。总体而言，这项研究应提供对在二羧酸存在下制备的水热还原石墨烯水凝胶的全面理解。发现长链DCA在极性溶剂中具有良好的分散性。总体而言，这项研究应提供对在二羧酸存在下制备的水热还原石墨烯水凝胶的全面理解。