Nonprecious Co-N-P-C@Mo₂TiC₂ Catalyst for the High-Performance Oxygen Reduction Reaction in PEMFCs

Abstract

The oxygen reduction reaction (ORR) has been considered as the rate-limiting step in proton-exchange membrane fuel cells. Therefore, noble metals such as Pt are used as catalysts, which restricts cost reduction. Nonprecious metals have attracted much attention as ORR catalysts, but the low catalytic activity and stability are still challenges associated with their use. Transition-metal/nitrogen/carbon (M-N-C) materials are widely used due to their low cost and relatively high activity. Electronic, compositional, and geometric effects offered by the metal–support interaction could enhance the catalytic activity and stability. In this study, MXene (Mo2TiC2), with high corrosion resistance and excellent electrical conductivity, is used as a support for Co-N-P-C to construct the Co-N-P-C@Mo2TiC2 catalyst. The half-wave potential of Co-N-P-C@Mo2TiC2 reaches 0.78 V, and the peak power density based on the catalyst reaches 880 mV cm–2. Co-N-P-C@Mo2TiC2 exhibits excellent stability in both ORR (only 18 mV loss after 10 000 cycles) and single-cell tests.

Manipulation of Electronic States of Pt Sites via d-Band Center Tuning for Enhanced Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cells

“…Furthermore, Pt–N–C exhibits a high cell voltage of 0.461 V when the current density reaches 1000 mA cm –2 , which also outperforms that of Pt/C (0.352 V), signifying the key role of the formation of the Pt–N–C catalyst with the coupling effect of Pt active sites (Figure c). In addition to its high activity, the cycling ability is also investigated by continuous operation at 100 mA cm –2 ; the Pt–N–C-driven PEMFC shows negligible degradation of catalytic activity after 6 h (Figure d), which is comparable or superior to the latest reported MEA performance with low Pt loading and non-Pt-based materials, , manifesting the distinguished robustness of the Pt–N–C-built cathode and demonstrating greatly promising application in practical energy devices.…”

Mo-Based MXene-Supported Pt Nanoparticles for Highly Durable Oxygen Reduction in Acidic Electrolytes

“…The lattice confinement between Ru nanoparticles and 2D TiO 2 greatly alters the electronic structure of Ru nanoparticles and eventually changes the adsorption of surface species (H ad , OH ad , CO, and so on) . Dual-transition metal MXene with abundant surface Mo vacancy was reported as having developed catalytic activity and stability due to the strong metal–support interaction. , However, the ORR performances of Mo-based dual-transition metal MXenes as supports of Pt are still unknown. Given the above considerations, we synthesized Mo-based MXenes (Mo 2 TiC 2 F x , Mo 2 CF x , and Mo 2 Ti 2 C 3 F x ) and studied their ORR performances as supports of Pt nanoparticles in this work.…”