Insights into the role of Co3O4/Ti3C2 MXene hybrid material in photoelectrochemical water oxidation over BiVO4 photoanode

• Published in: Journal of environmental chemical engineering 2024-06, Vol.12 (3), p.113058, Article 113058
• Main Authors: Jahangir, Tahir Naveed, Kandiel, Tarek A., Fatima, Wajiha, Abdalmwla, Mohammed A., Al-Ahmed, Amir, Ahmed, Amira Y.
• Format: Article
• Language: English
• Subjects: Hole transport layer; Hybrid materials; MXenes; Photoelectrochemical cells; Water Oxidation Catalysts
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2024.113058

Developing efficient hole transport layers and water oxidation electrocatalysts is vital for improving the performance of photoelectrochemical (PEC) devices for water-splitting. In this work, we synthesized Co3O4 nanoparticles/Ti3C2-MXene hybrid material and utilized it as a dual-function material to transport the photogenerated holes and catalyze the water oxidation reaction. It was found that the modification of BiVO4 with Co3O4/Ti3C2-MXene prolonged the lifetime of the photogenerated holes by 13.7-fold (i.e. from 0.26 s for BiVO4 to 3.56 s for Co3O4/Ti3C2/BiVO4) and significantly reduced the charge transfer resistance. The modification of BiVO4 with only Ti3C2-MXene resulted in significant surface recombination more likely due to the high concentration of the accumulated holes in the Mxene layer because of its low electrocatalytic activity toward water oxidation reaction. Employing the Co3O4/Ti3C2-MXene hybrid material significantly reduced the rate constant of surface recombination and dramatically enhanced the charge transfer efficiency (i.e. from 0.17% for BiVO4 to 14.0% for Co3O4/Ti3C2/BiVO4 at 0.65 VRHE). Under optimized conditions, the Co3O4/Ti3C2/BiVO4 photoanode was able to deliver 5.05 mA cm−2 at 1.23 VRHE and outperforms Ti3C2/BiVO4 and Co3O4/BiVO4 photoanodes. Moreover, it showed high stability for over 50 hours and reached a Faradaic efficiency of 90%. An applied bias photo-to-current efficiency (ABPE) value of 1.71% at 0.62 VPt was obtained for the overall water splitting. This work provides a facile method to reduce surface recombination and enhance the stability and PEC efficiency of BiVO4 photoanodes via the modification with dual-function oxygen evolution catalyst/hole transport layer hybrid material. [Display omitted]