Visible Light-Responsive Bimetallic Mo ₂ TiC ₂ MXenes for Enhanced Hydrogen Evolution Performance

Utilizing sunlight to drive catalytic reactions presents a sustainable approach toward carbon-negative industrial processes. However, efficient solar-to-chemical energy conversion remains limited by insufficient light absorption capabilities of conventional catalytic materials. Herein, we report for the first time that the bimetallic Mo2TiC2Tx MXene─a two-dimensional transition metal carbide─functions as a visible-light-responsive photocatalyst for hydrogen evolution. The Mo2TiC2Tx MXene was synthesized via a novel etching method using NH4BF4 in combination with H2SO4, effectively removing the aluminum (Al) layer from the Mo2TiAlC2 MAX phase. The resulting delaminated Mo2TiC2Tx (d-Mo2TiC2Tx) exhibited a photocurrent density of 0.512 mA/cm2 at 0 V vs RHE under visible light irradiation. Notably, d-Mo2TiC2Tx showed a 50% enhancement in photocurrent compared to multilayered Mo2TiC2Tx (m-Mo2TiC2Tx). Furthermore, d-Mo2TiC2Tx demonstrated excellent chemical stability in harsh acidic conditions (1.0 M H2SO4), highlighting its potential for application in photodriven water splitting.