Effect of reducing agents on co-precipitation synthesis of titanium dioxide/reduced graphene oxide composite materials for upgrading the performance of dye-sensitized solar cells

[Display omitted] •TiO2/rGO composite materials was synthesized by the co-precipitation method.•Potential reducing agents had been investigated with the co-precipitation synthesis.•The compared performance of DSSCs showed the effect of various reducing agents concurrently.•Ascorbic acid, sodium borohydride, and hydrazine were the appropriate reducing agents. Herein, titanium dioxide/reduced graphene oxide (TiO2/rGO) composite material was synthesized using the co-precipitation method to investigate reducing agents. The as-prepared TiO2/rGO composite material was employed to fabricate photoanode in dye-sensitized solar cells (DSSCs). Experimental results showed that the reducing agents were essential in reducing GO into rGO. Still, they also had a significant influence on the bonding of rGO with TiO2, leading to the narrowing of band-gap energy photoanode material and enhancement of DSSCs performance. The high performance was recognized for DSSCs using ascorbic acid (6.94 %), hydrazine (7.08 %), and sodium borohydride (7.17 %), while low counterpart was affirmed to sodium citrate (5.54 %), and d-glucose (4.63 %) in comparison with pure TiO2 (6.82 %). Therefore, the findings from this research are highly expected to pave the way for optimizing co-precipitation synthesis of TiO2/rGO composite based on the favorable reducing agents, ultimately applying for the fabrication of DSSCs commercially.