In the last few years, graphene-based semiconductor photocatalysts have fascinated cosmic interest for improved photocatalytic performance.22,23 Among those photocatalysts graphene has been demonstrated as an efficient electron acceptor to enhance the charge transfer and effectively reduce recombination of the electron–hole pairs in the composite to improve the photocatalytic activity. In 2010, Kamat and coworkers pioneered the enhancement of the photocatalytic activity of graphene based semiconductor–metal composites.24 Zhang et al. showed that the TiO2–graphene nanocomposite leads to the enhanced photocatalytic degradation of organic pollutants.25 Xiang et al. studied different photocatalysts such as graphene–C3N4 composite, graphene modied TiO2 nanosheet and MoS2–graphene modied TiO2 nanoparticles for the enhanced photocatalytic hydrogen production under visible light.26–28 Most recently, Yeh et al. have shown that GO could act as an active photocatalyst for water splitting.29 The inherent wide bandgap of GO opens up the possibilities for photocatalytic applications such as CO2 to methanol conversion, which simultaneously performs solar energy harvesting and CO2 reduction. In this article, systematic investigation of GO for the photocatalytic CO2 reduction process has been performed based on various GOs synthesized under different conditions. Morphological and elemental characterizations of GOs have been applied to correlate with the photoreduction result to provide better understanding. The quantitative and qualitative determinations of the methanol formation were performed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS).