Platinum-nickel nanocrystals anchored on heteroatom-functionalized Ti3-xC2Ty MXene 3D porous architecture for electrocatalytic hydrogen evolution in alkaline electrolytes.

• A unique PtNi@PS-TCT nanohybrid electrocatalyst for alkaline H 2 evolution. • The 3D porous spatial configuration of MXene facilitates fast dynamics and long-term stability. • The heteroatom-functionalized and Ti³⁺ defect decorated MXene provides abundant active sites. • The strong bimetal-substrate interfacial interaction promotes directional charge transfer. • The remarkable catalytic activity with low overpotentials of 56.1 mV at 10 mA cm⁻². Rational design and construction of efficient electrocatalysts are crucial for enhancing the activity and stability of the hydrogen evolution reaction (HER) in alkaline electrolytes. Herein, heteroatom (phosphorus and sulfur)-functionalized and self-adapting Ti³⁺ species defect decorated Ti 3-x C 2 T y MXene (PS-TCT) with 3D porous architecture for anchoring platinum-nickel (PtNi) bimetallic nanocrystals for alkaline electrocatalytic HER. Experimental and theoretical studies have shown that the heteroatoms delicately modulated the electronic configuration of MXene to optimize the adsorption capacity of the reaction intermediates. The 3D porous spatial configuration of PS-TCT with abundant Ti³⁺ species defect endowed an efficient channel for charge transfer and sufficient catalytically active sites, thus facilitating fast dynamics and long-term stability. Additionally, the strong bimetal-substrate interfacial interaction (Pt-S bonding) between PtNi and PS-TCT established an electron directional transport channel, thus achieving valid and stable interfacial electron transport. Consequently, the optimized PtNi@PS-TCT nanohybrids showed remarkable catalytic activity with low overpotentials of 56.1 mV at 10 mA cm⁻² and impressive Tafel slope of 81 mV dec⁻¹ for HER in alkaline electrolytes (1.0 M KOH), while exhibiting outstanding electrochemical stability. This work offers a constructive route for precisely constructing high-performance multifunctional composite electrocatalysts. [Display omitted] [ABSTRACT FROM AUTHOR]