Avinash Rundla, Priyanka, Bheem Kumar, Mahaveer Singh, Vikash Mishra, Kedar Singh
Abstract MXenes, an emerging 2D material group, hold high microstructural stability, superior conductivity, and a huge surface area, enabling effective atom utilization for electrocatalytic hydrogen evolution (HER). Herein, rGO-integrated (Ti3C2TX)100-y(rGO)y (y = 0, 5, 10, 15, 100) nanocomposites were fabricated via ultrasonic-mediated self-assembly to demonstrate composition-dependent HER behavior. The incorporation of rGO nanosheets serves as an effective spacer that suppresses MXene self-stacking, improves electronic connectivity, and provides robust electrolyte accessibility. Among all compositions, (Ti3C2TX)90(rGO)10 catalyst delivers optimal HER performance, as 10 wt % rGO forms a continuous conductive network without obstructing active sites. Lower rGO ratios are inadequate to achieve electronic percolation, while surplus rGO induces interlayer shielding, collectively highlighting the superiority of the composition-optimized 90:10 framework in promoting charge-transfer kinetics, active-site exposure, and electrocatalytic performance. The (Ti3C2TX)90(rGO)10 hybrid unveiled an excellent electrocatalytic response with an overpotential of 131.33 mV at 10 mA cm–2 current density, outperforming pristine MXene. The reduced Tafel slope and lower Rct confirm accelerated kinetics empowered by rGO-facilitated conductive pathways, while a durability test discloses 73% stability after 27.5 h of continuous operation. DFT + U calculations elucidate the catalytic mechanism, revealing a near-optimal Gibbs free energy (ΔGH* = −0.08 eV) and notable adsorption energetics arising from strong interfacial coupling at the Ti3C2TX/rGO heterojunction, thereby underscoring rGO’s discerning involvement in modulating the electronic structure and remediating the catalytic efficiency of Ti3C2TX MXene-based electrocatalysts for next-generation HER applications and sustainable energy conversion technologies.