Significant efforts have been focused on the development of non-noble metal electrocatalysts for efficient production of green hydrogen using renewable energy sources such as water and sunlight. Various transition metal oxides have been explored as promising candidates for hydrogen evolution reactions (HER), attracting considerable attention in the field of water splitting. In this study, we report the synthesis of anatase phase TiO₂ nanoparticles (NPs) with a crystallite size of 6.94 nm, achieved through a co-precipitation method specifically for neutral water electrochemical HER applications. The as-synthesized anatase phase of TiO₂ electrocatalyst have been characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and ultraviolet visible spectroscopy. Transmission electron microscopy analysis revealed that the average particle size of the TiO₂ NPs was approximately 5.80 nm. The exceptional HER performance of these nanoparticles can be attributed to their optimal crystallite size, rapid charge transfer kinetics, and reduced band gap energy. The electrocatalyst demonstrated an overpotential of 470 mV to achieve a current density of 10 mA cm^-2 in a 0.2 M Na₂SO₄ electrolyte. Furthermore, the electrode maintained stable HER activity over a continuous period of 50 h, indicating its potential for practical applications. These findings highlight the critical role of crystallite size optimization in enhancing HER activity, particularly in neutral electrolytes. By advancing the understanding of non-noble metal electrocatalysts, this study contributes to the ongoing efforts to develop efficient, sustainable methods for green hydrogen production, aligning with global goals for renewable energy utilization.

Prashant D. Sanadi

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