Efficient hydrogen evolution by using two-dimensional EMOF(Ti)/MAX-Cu novel photocatalysts synthesized via the bi-phase emulsification method

Abstract

In this study, a bi-phase emulsification method was employed for the first time to synthesize a novel Ti-based metal–organic framework (Ti-MOF), referred to as EMOF(Ti). And it was utilized for in situ composite modification of the Ti₃AlC₂ MAX material (MAX-Cu) after treatment with dilute nitric acid and glucose-reduced copper. This approach successfully fabricated EMOF(Ti)/MAX-Cu composite photocatalysts. The photocatalytic hydrogen production performance of these composites was examined under full-wavelength illumination. Additionally, the morphology, structure, and crystalline properties of the materials were characterized and evaluated. The experimental results demonstrated that the as-prepared composite remarkably enhanced the overall photoresponse of the materials while effectively redistributing photogenerated electrons during the photocatalytic process. This accelerated the separation and migration of photogenerated charges and suppressed the recombination of electron–hole pairs. The oxygen vacancies and copper metal defects introduced during the modification process provided additional active sites, which further facilitated the photocatalytic reaction. Notably, the 10% EMOF(Ti)/MAX-Cu composite achieved the highest hydrogen production rate of 3503.6 μmol g⁻¹ h⁻¹, representing increases of 15.3 and 32.1 times compared to EMOF(Ti) (228.3 μmol g⁻¹ h⁻¹) and MAX (109.0 μmol g⁻¹ h⁻¹), respectively. These findings indicate that the composite formation was conducive to enhancing the efficiency and performance of hydrogen production in the photocatalytic system.