Unlocking interfacial effects in NiTiO3-TiO2 eutectic composite: Enhancing overall electrocatalytic and photoelectrochemical water splitting

• Published in: Fuel (Guildford) 2025-02, Vol.381, p.133273, Article 133273
• Main Authors: Saha, Sanjit, Devi, Assa Aravindh Sasikala, Kolodziejak, Katarzyna, Tymicki, Emil, Vadivel, Govindan, Pawlak, Dorota A.
• Format: Article
• Language: English
• Subjects: Eutectic-composite; Heat Treatment; Interface; Overall water-splitting; Photo-anode
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.133273

[Display omitted] •NiTiO3-TiO2 eutectic composite were prepared by micro pulling-down methods.•Abundant interfaces and oxygen vacancies promoted interfacial charge transfer.•NiTiO3-TiO2 shows a very small HER overpotential of 80 mV (at 10 mA/cm2)•NiTiO3-TiO2 shows a very small OER overpotential of 120 mV (at 50 mA/cm2)•NiTiO3-TiO2 exhibited a photocurrent of 3.5 mA/cm2. This study introduces a novel approach to tackle the urgent demand for catalysts possessing both bifunctional capabilities and efficient photocatalytic properties. By employing the micro-pulling down method, a NiTiO3/TiO2 eutectic composite is synthesized, creating an interface rich structure. This composite is utilized as a photo-anode, displaying a significant photocurrent of 3.5 mA/cm2 at 1.4 V. Through annealing in an H2 atmosphere, the catalytic performance is finely adjusted, revealing distinct electrochemical activities at the interface of NiTiO3 and TiO2. Enhanced interfacial adsorption is confirmed by scanning electrochemical microscopy post-annealing. Remarkably, the annealed NiTiO3/TiO2 exhibits outstanding overall water-splitting efficiency, with minimal overpotentials of 80 mV (at 10 mA/cm2) and 120 mV (at 50 mA/cm2) for the HER and OER, respectively. The low Tafel slope (41 mV dec-1) underscores rapid water splitting kinetics. Density functional theory (DFT) calculations suggest that NiTiO3-TiO2 heterostructure can enhanced the catalytic properties of the surface providing higher adsorption of the electrolyte ions during catalytic reactions. This study establishes a straightforward crystal growth strategy for the design of highly effective, enduring, and bifunctional photocatalytic catalysts, signaling promising advancements in water splitting technology.