Tailoring hierarchical porous TiO2 based ternary rGO/NiO/TiO2 photocatalyst for efficient hydrogen production and degradation of Rhodamine B

Abstract

This study reports a facile and cost effective approach for synthesizing a ternary photocatalyst rGO/NiO/TiO2 (RGNPT) based on three-dimensionally hierarchical porous TiO2 (PT) particles, rGO and NiO as a cocatalyst for efficient photocatalytic hydrogen generation. The efficient junction architecture of RGNPT was observed from the TEM study. The composite's morphology was tuned by varying the weight ratio variation of graphene oxide (5, 7.5, and 10 Wt%). The obtained material showed impressive photocatalytic efficiency for H2 production in aqueous methanol suspension. The p-n junction hybrid composite RGNPT-7.5Wt% showed superior activity towards H2 production yield 8,215 µmolg−1 after 4 h of light irradiation and apparent quantum yield efficiency 9.19%. The photocatalyst shows promising results of 88% of photo-degradation efficiency to Rhodamine B (Rh-B) dye. The RGNPT-7.5Wt% demonstrated the higher current density 0.16 µAcm−2 whereas NiO-porous TiO2 (NPT) showed ten folds lower of 0.017 µAcm−2 using Ag/AgCl electrode. The electron impedance spectroscopic results of RGNPT-7.5Wt% heterostructure exhibited higher photocurrent response and lower charge transfer resistance and significantly accelerate the electrons transfers across the NPT and NiO. Photoluminescence lifetime of RGNPT-7.5Wt% (τ = 3.21 ns) is 16 times higher than porous TiO2 (τ = 0.10 ns). This work manifestates that hierarchical porous TiO2 and rGO graphene plays a vital role in the electron transfer pathway, which is further considered an excellent strategy for synthesizing the ternary composites and enhancing photocatalytic hydrogen production.