This study provides a significant enhancement in CO₂ photoconversion efficiency by the functionalization of a reduced graphene oxide/cadmium sulfide composite (rGO/CdS) with amine. The amine-functionalized graphene/CdS composite (AG/CdS) was obtained in two steps. First, graphene oxide (GO) was selectively deposited via electrostatic interaction with CdS nanoparticles modified with 3-aminopropyltriethoxysilane. Subsequently, ethylenediamine (NH₂C₂H₄NH₂) was grafted by an N,N′-dicyclohexylcarbodiimide coupling reaction between the amine group of ethylenediamine and the carboxylic group of GO. As a result, a few layers of amine-functionalized graphene wrapped CdS uniformly, forming a large interfacial area. Under visible light, the photocurrent through the AG/CdS significantly increased because of enhanced charge separation in CdS. The CO₂ adsorption capacity on AG/CdS was 4 times greater than that on rGO/CdS at 1 bar. These effects resulted in a methane formation rate of 2.84 μmol/(g h) under visible light and CO₂ at 1 bar, corresponding to 3.5 times that observed for rGO/CdS. Interestingly, a high methane formation rate (1.62 μmol/(g h)) was observed for AG/CdS under CO₂ at low pressure (0.1 bar), corresponding to a value 20 times greater than that observed for the rGO/CdS. Thus, the enhanced performance for photocatalytic reduction of CO₂ on the AG/CdS is due to the improved CO₂ adsorption related to the amine groups on amine-functionalized graphene, which sustains the strong absorption of visible light and superior charge-transfer properties in comparison with those of graphene.

中文翻译：

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胺官能化石墨烯/ CdS复合材料对光催化还原CO _2的影响

这项研究通过用胺还原的氧化石墨烯/硫化镉复合材料（rGO / CdS）的功能化，大大提高了CO _2的光转化效率。分两步获得胺官能化的石墨烯/ CdS复合材料（AG / CdS）。首先，通过与3-氨基丙基三乙氧基硅烷改性的CdS纳米粒子之间的静电相互作用，选择性沉积氧化石墨烯（GO）。随后，将乙二胺（NH ₂ C ₂ H ₄ NH ₂）通过N，N接枝。乙二胺的胺基与GO的羧基之间的'-二环己基碳二亚胺偶联反应。结果，几层胺官能化的石墨烯均匀地包裹了CdS，形成了较大的界面面积。在可见光下，由于CdS中电荷分离的增强，通过AG / CdS的光电流显着增加。在1 bar的压力下，AG / CdS上的CO ₂吸附能力是rGO / CdS上的CO ₂吸附能力的4倍。这些作用导致可见光和1 bar的CO ₂下的甲烷形成速率为2.84μmol/（gh），相当于rGO / CdS的3.5倍。有趣的是，在CO ₂条件下，AG / CdS的甲烷生成率很高（1.62μmol/（gh））在低压（0.1巴）下，对应的值比rGO / CdS所观察到的值大20倍。因此，在AG / CdS上光催化还原CO _2的性能增强是由于与胺官能化石墨烯上的胺基相关的CO ₂吸附得到了改善，从而保持了可见光的强吸收性和优异的电荷转移性能。与石墨烯的比较。