PtGd/Gd2O3 alloy/metal oxide composite catalyst for methanol oxidation reaction

Pt-transition metal alloys are frequently used to improve the catalytic activity for methanol oxidation reaction. However, the severe dealloying strongly limits the applications of Pt-based alloy in fuel cells. Recently, Pt-rare earth metal alloys are considered to be the promising catalysts for electrocatalytic application in fuel cells. Metal oxide as the co-catalytic component of composite catalyst, is also applied to regulate the electronic structure and strengthen resistance to CO poisoning. In this work, we utilized hydrogen reduction method to prepare PtGd/Gd2O3 composite catalyst. X-ray diffraction result illustrates that both Gd2O3 and PtGd alloy co-exist in PtGd/Gd2O3 material. X-ray photoelectron spectroscopy data confirms that the main valence states of Pt and Gd are metal form in the PtGd/Gd2O3 catalyst and emerges obvious transfer of element binding energy. Transmission electron microscopy data presents that composite PtGd/Gd2O3 particles are uniformly dispersed on the carbon power with a typical core-shell structure. And upon the increase of Gd precursor in reduction process, the metal oxide layer becomes more thicker for PtGd/Gd2O3 composite material. Because of the synergistic contributions given by the Pt–Gd bimetals and alloy-metal oxide between PtGd alloy and Gd2O3 oxide, the PtGd/Gd2O3 composite catalysts exhibit superior catalytic performance toward methanol oxidation reaction. Specifically, the mass activity of Pt1Gd1/Gd2O3 is about 1.9 times that of commercial Pt/C; besides this, the optimal specific activity of Pt1Gd2/Gd2O3 is almost 4 times that of commercial Pt/C. More importantly, the Pt1Gd1/Gd2O3 emerged a 20.9% degradation after 8000 cycles test, while commercial Pt/C showed a 61.7% degradation. And this work provides an important insight for rare earth elements investigation on the electrocatalysis application in fuel cells.