Platinum nanoparticles decorated Nb2CTx MXene as an efficient dual functional catalyst for hydrogen evolution and oxygen reduction reaction

Here, a dual functional Nb2CTx@Pt nanocomposite has been synthesized by in situ reduc-tion method. The Pt loading in the composite has been optimized to get minimum over -potential (141 mV at 10 mA/cm2) for hydrogen evolution reaction (HER) along with a promising Tafel slope of 46.3 mV/dec, while Pt/C shows an overpotential and Tafel slope of 104 mV and 32.4 mV/dec, respectively. The Pt mass activity for Nb2CTx@Pt3.8 composite at 100 mV overpotential was 3.44 A g-1 while the Pt mass activity for conventional Pt/C was 0.7 A g-1, which shows that the activity of Nb2CTx@Pt3.8 composite is approximately 5 times higher than Pt/C. In addition, the catalyst was found to be stable for continuous 500 cycles without any binder molecules. The oxygen reduction reaction (ORR) capability of the material was also evaluated and found that the catalyst exhibited a current density of -4.28 mA/cm2 in the diffusion limiting region in comparison with the current density of -5.82 mA/cm2 for Pt/C at 2600 revolutions per minute (RPM). The Pt mass activity of Nb2-CTX@Pt3.8 composite for ORR is approximately 10 times higher than Pt/C. The Nb2CTX@-Pt3.8 composite was able to reduce O2 completely using the 4-electron pathway with very little peroxide production. From these results, the dual functionality of the Nb2CTX@Pt3.8 composite for both HER and ORR has been established.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.