Research data supporting publication "Anisotropic Heterobimetallic Nanomaterials with Controlled Composition for Efficient Oxygen Reduction at Ultralow Loading"

Research data supporting the full paper entitled "Anisotropic Heterobimetallic Nanomaterials with Controlled Composition for Efficient Oxygen Reduction at Ultralow Loading" by Ming, Cobb, Rahaman, Sammy, Reisner and Wheatley. A series of PtM (M = Ni, Co) nanopods and nanodendrites were prepared under a range of chemically reductive conditions. Products were analysed for composition, morphology and particle size. These and corresponding PtFe nanoparticles (previously reported by Ming and Wheatley) were then tested in ORR under alkaline conditions. The following supporting data are presented: For transmission electron microscopy (TEM) analysis, products dispersed in hexane were sonicated then drop-cast onto a lacey carbon 300 mesh copper grid. This was plasma cleaned (Fischione Model 1070 Nanoclean). Analysis was performed using a Thermo Scientific (FEI) Talos F200X G2 TEM operating at 200 kV. Images were acquired with a Ceta 4k x 4k CMOS camera. Energy dispersive X-ray (EDX) analysis used scanning TEM (STEM) mode. Images were acquired with a high-angle annular dark field (HAADF) detector and EDX spectra/maps were collected using a Super-X detector system with 4 windowless silicon drift detectors. Inductively-coupled plasma-optical emission spectroscopy (ICP-OES) analysis for Ni, Co and Pt used a Thermo Fisher Scientific iCAP 7400 ICP-OES spectrometer against standard curves (0.01-10 ppm). Standards were prepared by diluting a commercial ICP-OES standard (Sigma-Aldrich) with 2% HNO3. Powder X-ray diffraction (XRD) patterns were obtained on a PANalytical Empyrean diffractometer fitted with an X’celerator detector and a Cu-Kα1 (λ = 1.5406 Å) source, with step size 0.002° and scanning speed 0.022° s−1 at 40 kV and 40 mA. For electrode preparation and oxygen reduction tests, electrocatalysts were dispersed in ethanolic Nafion and drop-cast onto a glassy carbon rotating-disk electrode (Pine Research Instrumentation, E6R1 ChangeDisk). Separately, commercial standard 10 wt% Pt/C were also prepared. For testing, oxygenwas bubbled through 1 M aqueous KOH. LSV measurements were taken at room temperature against a Pt mesh counter electrode and a Ag|AgCl reference electrode with a rotation speed of 1600 rpm and sweep rate of 20 mV/s. An Ivium CompactStat bipotentiostat was used for all measurements. Mass activity was calculated based on ICP-OES results.