Synthesis of Ag/Cu decorated 3D self-assembled nanowire TiO2 Photocatalyst for Hydrogen Production: A Promising Pathway towards Sustainable Energy Generation

Abstract Here synthesis and characterization of TiO₂ with different morphologies along with the cost-effective bimetallic decoration on optimized 3D self-assembled nanowire TiO₂ (NWT) photocatalyst (Ag/Cu-NWT) with overwhelming hydrogen production rate is reported. All the photocatalysts were well characterised by different characterization techniques. Initially, the effect of morphology change obtained by changing the NaOH concentration has been studied for TiO₂. Morphology obtained at 10 M NaOH solution i.e., NWT (678 μmol/g) showed better hydrogen production than morphology obtained at 5M (410 μmol/g), 15M (210 μmol/g) and 20M (160 μmol/g) NaOH solutions. Further with the aim to achieve comparable or better activity low cost photocatalyst as compared to Pt-TiO₂ system, NWT was decorated with various Cu percentages and then with minimal percentage of Ag on optimized Cu-NWT photocatalyst. The observed trend for photocatalytic hydrogen production has been found to be P25 TiO₂ < NWT < 1.0Cu-NWT < 0.5Pt-NWT ≤ 0.1Ag/1.0Cu-NWT. The marked increase by a factor of 103 in hydrogen production for the optimized bimetallic 0.1Ag/1.0Cu-NWT (10,184 μmol/g) photocatalyst compared to P25 TiO₂ (99 μmol/g), nearly threefold increment in hydrogen production than optimized 1.0 Cu-NWT (3,907 μmol/g) photocatalyst and comparable hydrogen production as compared to 0.5Pt-NWT (10,050 μmol/g) may be attributed to the successful synthesis of a highly porous NWT morphology, which offers large surface area, increased light absorption combined with the synergistic effects of surface plasmon resonance (SPR) and the Schottky barrier for H⁺ reduction to H₂ gas. The optimization of TiO₂ morphology and inexpensive bimetallic decoration strategy opens up promising opportunities for the development of cost-effective photocatalysts in the realm of energy and environment.