In Situ Formed Pt₃Ti Nanoparticles on a Two-Dimensional Transition Metal Carbide (MXene) Used as Efficient Catalysts for Hydrogen Evolution Reactions

Abstract

The design of efficient catalysts capable of delivering high currents at low overpotentials for hydrogen evolution reactions (HERs) is urgently needed to use catalysts in practical applications. Herein, we report platinum (Pt) alloyed with titanium (Ti) from the surface of Ti3C2T x MXenes to form Pt3Ti intermetallic compound (IMC) nanoparticles (NPs) via in situ coreduction. In situ X-ray absorption spectroscopy (XAS) indicates that Pt undergoes a temperature-dependent transformation from single atoms to intermetallic compounds, and the catalyst reduced at 550 °C exhibits a superior HER performance in acidic media. The Pt/Ti3C2T x -550 catalyst outperforms commercial Pt/Vulcan and has a small overpotential of 32.7 mV at 10 mA cm–2 and a low Tafel slope of 32.3 mV dec–1. The HER current was normalized by the mass and dispersion of Pt, and the mass activity and specific activity of Pt/Ti3C2T x -550 are 4.4 and 13 times higher, respectively, than those of Pt/Vulcan at an overpotential of 70 mV. The density functional theory (DFT) calculations suggest that the (111)- and (100)-terminated Pt3Ti nanoparticles exhibit *H binding comparable to Pt(111), while the (110) termination has an *H adsorption that is too exergonic, thus poisoned in the low overpotential region. This work demonstrates the potential of MXenes as platforms for the design of electrocatalysts and may spur future research for other MXene-supported metal catalysts that can be used for a wide range of electrocatalytic reactions.

The dynamics of overlayer formation on catalyst nanoparticles and strong metal-support interaction

“…4a), which showed a shift in the Bragg reflection of the platinum towards higher angles after reduction at 600°C. Incorporation of titanium into the platinum crystal structure causes lattice contraction, as was observed previously for the Pt 8 Ti alloy and for other platinum alloys, which formed upon high-temperature reduction [34][35][36][37] . The unit cell contracted from 3.921 to 3.919 Å after reduction at 600°C, as deduced by means of the Pawley fitting (Fig.…”

Multilayer stabilization for fabricating high-loading single-atom catalysts

“…The electrochemical HER performances of Ru-SA-NSFC, Ir-SA-NSFC, and Pt-SA-NSFC were also studied. The overpotentials at a current density of 10 mA cm −2 of Ru-SA-NSFC, Ir-SA-NSFC, and Pt-SA-NSFC were 62, 67 and 45 mV, respectively, implying comparable HER activities with reported noble metal-based electrocatalysts (Supplementary Table 12) [57][58][59][60][61][62] .…”

Ultrastable MXene@Pt/SWCNTs' Nanocatalysts for Hydrogen Evolution Reaction

“…[6,7] Considering the low abundance of Pt on the earth, [8,9] building heterogeneous Pt-based nanocatalysts has therefore become a practical approach to maximize activity and durability while minimizing the usage of precious Pt resource. [10][11][12][13][14][15][16] Nano/atomic Pt species are frequently supported on carbon-based materials because of their good conductivity and chemical stability. These carbon materials include, but not limited, to carbon black, graphene, and porous carbon.…”