Pd‐Enriched‐Core/Pt‐Enriched‐Shell High‐Entropy Alloy with Face‐Centred Cubic Structure for C₁ and C₂ Alcohol Oxidation

Abstract

High‐entropy alloy nanoparticles (HEA NPs) have aroused great interest globally with their unique electrochemical, catalytic, and mechanical properties, as well as diverse activity and multielement tunability for multi‐step reactions. Herein, a facile low‐temperature synthesis method at atmospheric pressure is employed to synthesize Pd‐enriched‐HEA‐core and Pt‐enriched‐HEA‐shell NPs with a single phase of face‐centred cubic structure. Interestingly, the lattice of both Pd‐enriched‐HEA‐core and Pt‐enriched‐HEA‐shell enlarge during the formation process of HEA, with tensile strains included in the core and shell of HEA. The as‐obtained PdAgSn/PtBi HEA NPs show excellent electrocatalytic activity and durability for methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). The specific (mass) activity of PdAgSn/PtBi HEA NPs for MOR is 4.7 mA cm−2 (2874 mA mg(Pd+Pt)−1), about 1.7 (5.9) and 1.5 (4.8) times higher than that of commercial Pd/C and Pt/C catalysts, respectively. Additional to high‐entropy effect, Pt sites and Pd sites on the interface of the HEA act synergistically to facilitate the multi‐step process towards EOR. This study offers a promising way to find a feasible route for scalable HEA manufacturing with promising applications.

Confined Growth of Palladium Nanoparticles on Nanographdiyne: A Model Study of Bulk Graphdiyne–Metal Covalent Interaction

“…Besides, the peak current ratio of the positive scan (I f ) to negative scan (I b ), I f /I b , represents the ability to tolerate the poisoning of carbonaceous species. The 200Pd/ 1 shows an I f /I b of 2.8, which is higher than those of Pd 1 Cu 1 (0.8), Au@Pt 1 –Pd 1 H-Ss (1.1), Pd-UNs/Cl-GDY (1.8) 50 , PdAgSn/PtBi HEA NPs (1.9), and Pd(20%)-CeO 2 (20%)/NMCS (2.3), implying a good methanol tolerance and sufficient active sites for methanol adsorption and conversion. The CO stripping tests were also conducted to evaluate the poisoning tolerance of the catalysts.…”

Monodisperse Sea-Urchin-like Nanodendrites and Nanoparticles of Multicomponent Pd-Based Alloys for Enhanced C2 Alcohol Oxidation Activity

“…The C 1 pathway is limited due to the difficult breaking of the C–C bond . Interestingly, each step of an oxidation reaction that requires electron transfer requires the participation of hydroxide (OH*). ,, …”

“…Meanwhile, the monodisperse sea-urchin-like PdPbBi NDs and PdPbSn NDs can be obtained by replacing AgNO 3 with bismuth­(III) nitrate pentahydrate (Bi (NO 3 ) 3 ·5H 2 O) and tin­(II) chloride dihydrate (SnCl 2 ·2H 2 O), respectively (see the Experimental Section for more details). The key to this approach is the coreduction of metal precursors (Pd 2+ , Pb 2+ , Ag + , Bi 3+ , and Sn 2+ ) to form solid-solution alloys with a single phase. , …”

“…The EOR was chosen as a model to evaluate the catalytic activity based on monodisperse sea-urchin-like NDs and NP nanocatalysts to investigate the contributions of the morphology and electronic properties. , Figure a displays the cyclic voltammetry (CV) curves of monodisperse sea-urchin-like PdPbM (M = Ag, Bi, and Sn) NDs and PdPbM NPs in 1.0 M KOH, where the ECSA values of sea-urchin-like PdPbAg, PdPbBi, and PdPbSn NDs are 32.00, 65.21, and 60.25 m 2 g Pd –1 , while the corresponding values of PdPbAg, PdPbBi, and PdPbSn NPs are 69.78, 27.36, and 38.22 m 2 g Pd –1 (Figure S31), respectively. In comparison with commercial Pd/C (13.6 m 2 g Pd –1 ), all of the as-made samples show greatly enhanced ECSA values; this indicates that the synergistic effects would promote the catalytic behavior .…”

“…The CH 3 CH 2 OH* and OH* are absorbed on the surface. Under the C 1 /C 2 pathway, OH* would trigger the cleavage of the C–H bond of CH 3 CH 2 OH* to form CH 3 CHOH* (reaction, R 1 ) and then CH 3 CHO* generated through breaking the O–H bond ( R 2 ), followed by the further breaking of the C–H bond to form CH 3 CO* ( R 3 ), where the reactions react on the α-C atoms instead of β-C atoms with 3 electrons involved. ,, …”