Phase-Controlled Synthesis of Pd–Sn Nanocrystal Catalysts of Defined Size and Shape

Abstract

Bimetallic Pd-based nanoparticles (NPs) are of interest as electrocatalysts for formic acid electrooxidation (FAEO) because of their higher initial catalytic activity and CO tolerance when compared to Pt. Intermetallic NPs (i-NPs) with specific geometric and electronic structures generally exhibit superior catalytic activity, selectivity, and durability when compared to their disordered (random alloy) counterparts; however, the colloidal synthesis of i-NPs remains a challenge. Here, a one-pot method was demonstrated as a facile route to obtain monodisperse Pd−Sn NPs with phase control, including intermetallic hexagonal Pd 3 Sn 2 (P6 3 /mmc), intermetallic orthorhombic Pd 2 Sn (Pnma), and alloy cubic Pd 3 Sn (FCC, Fm3m) as size-controlled NPs with quasi-spherical shapes. Initial metal precursor ratios and reaction temperature were critical parameters to achieving phase control. Also, slight modifications of synthetic conditions resulted in either Pd 2 Sn nanorhombohedra or nanorods with tunable aspect ratios. A systematic evaluation of the Pd−Sn NPs for FAEO showed that most presented higher specific activities when compared to commercial Pd/C, in which Pd 2 Sn quasi-spheres and nanorhombohedra showed the highest catalytic activity for FAEO. These results highlight the benefits of phase-controlled Pd-based nanocatalysts with defined nanocrystal size and shape, with use of trioctylphospine (TOP) and oleic acid (OA) central to shape and size control.

Co-digestive ripening assisted phase-controlled synthesis of Ag–Sn intermetallic nanoparticles and their dye degradation activity

“…The formation of SnO x occurs on the surface of Ag 3 Sn nanoparticles in the aqueous reaction mixture used for photocatalysis and is anticipated to play an important role in dye degradation. The presence of a tin oxide layer on the surface of Sn-based intermetallic nanoparticles is a known phenomenon 71 and was even evident from the XPS data (Fig. 13).…”

Improvement of electrocatalytic alcohol oxidation by tuning the phase structure of atomically ordered intermetallic Pd-Sn nanowire networks

“…2c) can be indexed to the PdSn-Pnmb [20,43]. The (111) and (024) planes can be assigned to PdSn 2 -Aba2 [46]. The Pd-Sn OICs were selected and characterized by HAADF-STEM images, and the morphologies of the i-NNWs are shown in Fig.…”

“…The selected-area FFT analysis taken from Fig. 3b has a characteristic diffraction pattern of [211] zone [46]. The geometric phase analysis (GPA) was conducted and the strain distribution map is shown in Fig.…”

Synthesis of Alloyed Pd−Pb Nanowire Networks for Electrocatalytic Ethanol Oxidation with High Stability

“…Secondly, the added metal may oxidize the toxic carbon‐containing intermediate into the final product adsorbed on Pd by adsorbing hydroxide ions in the alkaline medium and then release the active sites of Pd [25,43,46–48] . Finally, the prepared alloy can increase the filling degree of the antibonding orbital by changing the d‐band center of Pd, thereby weakening the bonding force between Pd and the toxic carbon intermediate [4,49–57] . In spite of many environmental problems, lead remains a metal with great potential in EORs [57,58] .…”

“…[25,43,[46][47][48] Finally, the prepared alloy can increase the filling degree of the antibonding orbital by changing the d-band center of Pd, thereby weakening the bonding force between Pd and the toxic carbon intermediate. [4,[49][50][51][52][53][54][55][56][57] In spite of many environmental problems, lead remains a metal with great potential in EORs. [57,58] In this paper, we reported a simple hydrothermal method to synthesize PdÀ Pb alloys and compared the electrocatalytic properties of the prepared PdÀ Pb NNWs with different compositions by a variety of electrochemical testing methods.…”