A Coral-Like Mo2C/TiO2 Photoelectrode for Photoelectrochemical Water Splitting

Titanium dioxide (TiO2) is one of the most explored photoelectrode materials of water splitting for hydrogen generation. However, TiO2 has a bandgap of 3.2 eV, which restricts its energy absorption to UV light, and the photoexcited electrons and holes swiftly recombine. Thus, alteration of the band structure, such as by adding materials as cocatalysts, is needed. 2D molybdenum carbide (Mo2 C) has been researched extensively as an excellent non-noble cocatalyst owing to its Pt-like H+ adsorption capacity and high conductivity. In this work, composites of TiO2 and Mo2 C with four different compositions were produced using the sol-gel method, and their photoelectrochemical activity for water splitting was assessed. The composites were spin-coated onto FTO conducting glass, and FESEM analysis indicated that TiO2 nanoparticles are widely disseminated across Mo2 C to form coral-like structures. Analysis via X-ray diffraction verified the existence of peaks composed of TiO2 and Mo2 C. The sample containing 3% Mo2 C had the greatest increase in photocurrent density, which was approximately 1.56 mA cm-2 at a potential of 1.0 V against Ag/AgCl (1.59 vs. RHE), which is five times that of bare TiO2 . In addition, the composite’s onset potential moved to a lower potential. Our findings suggest that adding Mo2 C increases the hotoelectrochemical performance of the TiO2 photoelectrode. This work indicates the feasibility of employing Mo2 C as a cocatalyst to improve the performance of TiO2 for photoelectrochemical H2 production.