3D Ti3C2Tx-CNT composite supported Pt-based catalysts with enhanced oxygen reduction reaction activity

Platinum-based electrocatalysts have been widely used in proton exchange membrane fuel cells (PEMFCs) because of their excellent oxygen reduction reaction (ORR) activity. However, rapid corrosion and structural instability of conventional carbon supports severely limit the long-term operation and commercialization of PEMFCs. In this work, a three-dimensional composite support was constructed by integrating single-layer Ti3C2Tx (SL-Ti3C2Tx) with carbon nanotubes (CNTs). The one-dimensional tubular CNTs served as interlayer spacers and conductive skeletons between MXene nanosheets, thereby effectively suppressing sheet restacking and enabling the construction of Pt-based catalysts with well-defined three-dimensional architectures. Strong interfacial interaction between the composite support and Pt nanoparticles further enhanced the intrinsic electrocatalytic activity of the catalyst. The optimized Pt/Ti3C2Tx-CNT (2:1) catalyst exhibited excellent ORR activity, with an electrochemically active surface area (ECSA) of 247 m2 g−1, which was 3.1 times that of Pt/C, and a mass activity (MA) of 0.69 A mgPt−1, which was 8 times that of Pt/C. After 30 000 accelerated durability test cycles, Pt/Ti3C2Tx-CNT (2:1) retained approximately 79% of its ECSA and 83% of its MA, demonstrating excellent durability and corrosion resistance. The enhanced performance was mainly attributed to the unique three-dimensional Ti3C2Tx-CNT framework, which simultaneously improved Pt utilization, charge/mass transport, and support stability. This study provides a promising material system for high-performance PEMFC cathode catalysts and offers useful guidance for the rational design of durable electrocatalyst supports.