Electrochemical modification and structural characterization of porous PtNi/C catalyst

Abstract

The development of catalysts for high-efficient hydrogen evolution reaction (HER) is important for future sustainable energy conversion. Herein, porous carbon-supported PtNi alloy catalysts were fabricated by ion beam sputtering and ultrasonic-assisted electrochemical corrosion dealloying methods, and their performances toward the catalysis of HER were evaluated. The effects of corrosion dealloying on the hydrogen evolution activity, as well as stability, phase structure, surface composition, and active sites of PtNi alloys were analyzed by various analytical methods combined with orthogonal experiments. The results showed increased catalytic activity of HER by 51.39% after corrosion of the material in 0.2 mol/L H2SO4 at 40 °C for 0.5 h. The hydrogen evolution deteriorated as Pt-loading decreased by 25.83%, and corrosion temperature displayed significant influence. The pore structure of the catalyst surface raised the relative content of the exposed Pt element, and the zero-dimensional defect generated by the Ni atom deletion led to promotion in reaction area and active sites on the catalyst surface. The interplanar spacing of alloys (NiPt) was below 3%−6% of the standard value, and the lattice compressive strain of Pt was the reason that led to improved catalytic performance of PtNi alloy catalysts. The binding energy of the Pt 4f7/2 decreased by 0.74 eV, leading to enhanced electrochemical active sites and promoted hydrogen release.