Ti₃C₂T_z Supported Pulse-Electrodeposited Pt Nanostructures for Enhanced Acidic Electrochemical Hydrogen Evolution

Platinum (Pt)-based electrocatalysts are considered benchmark materials for the hydrogen evolution reaction (HER) in acidic solution. However, widespread use is limited by the high price of Pt. Tuning the Pt morphology to increase the catalytic surface area for the same mass loading is therefore essential to increase its utilization. Herein, single Ti₃C₂T_z flakes were deposited by electrophoresis onto a carbon-fiber gas diffusion layer, after which Pt nanostructures were selectively deposited onto the Ti₃C₂T_z flakes by pulse electrodeposition. It was observed that the pulse on-time (t_on) and duration had a significant effect on the morphology and activity of the composite electrode towards HER. Flower-like and spherical morphologies were produced at long and short values of t_on, respectively. As-synthesized electrocatalysts were studied for HER in 0.5 M sulfuric acid (H₂SO₄). The catalyst with the lowest Pt loading (10 μg/cm²), exhibited outstanding HER performance. It attained a current density of 10 mA/cm² at an overpotential of 38 mV, close to that of commercial carbon supported platinum (Pt/C, Vulcan XC). This catalyst exhibited a high turnover frequency (23.9 H₂ s⁻¹ @ 100 mV), small Tafel slope (41 mV/dec), and high mass-specific activity (2.45 A/mg_Pt @ 100 mV).