Hollow platinum nanospheres and nanotubes templated by shear flow-induced lipid vesicles and tubules and their applications on hydrogen evolution

Shear rate was utilized for synthesis of 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DC_8,9PC) vesicles and tubules in a microfluidic device. Lipid vesicles and tubules as templates were exploited to fabricate hollow platinum nanospheres and nanotubes, respectively, for the first time in a mild manner. The Pt nanosphere is ∼190 nm in diameter with wall thickness of ∼32 nm. The Pt nanotube is ∼280 nm in diameter and ∼30 μm in length with wall thickness of ∼15 nm. The Pt nanospheres and nanotubes as hydrogen evolution reaction (HER) catalysts both exhibited all-time high HER catalytic activity, with overpotentials of 31 and 27 mV at current densities of 10 mA cm^-2 and Tafel slopes of 23 and 21 mV dec^-1 respectively, in acidic electrolytes. The values of the exchange current density of Pt nanosphere and Pt nanotube catalysts are obtained as 0.87 and 0.93 mA cm^-2 by extrapolating the Tafel plot, which are larger than that of commercial Pt/C catalyst. Their catalytic activity can be maintained for at least 19 h.