Function‐Led Design of Aerogels: Self‐Assembly of Alloyed PdNi Hollow Nanospheres for Efficient Electrocatalysis

Abstract

One plausible approach to endow aerogels with specific properties while preserving their other attributes is to fine-tune the building blocks. However, the preparation of metallic aerogels with designated properties, for example catalytically beneficial morphologies and transition-metal doping, still remains a challenge. Here, we report on the first aerogel electrocatalyst composed entirely of alloyed PdNi hollow nanospheres (HNSs) with controllable chemical composition and shell thickness. The combination of transition-metal doping, hollow building blocks, and the three-dimensional network structure make the PdNi HNS aerogels promising electrocatalysts for ethanol oxidation. The mass activity of the Pd83 Ni17 HNS aerogel is 5.6-fold higher than that of the commercial Pd/C catalyst. This work expands the exploitation of the electrocatalysis properties of aerogels through the morphology and composition control of its building blocks.

Palladium Nanoparticles Anchored on Anatase Titanium Dioxide‐Black Phosphorus Hybrids with Heterointerfaces: Highly Electroactive and Durable Catalysts for Ethanol Electrooxidation

“…The mass peak current density of the Pd/ATN-BP catalyst is very high with a value of 5023.8 mA mg Pd ), respectively. Compared with, the mass peak current density of the Pd/ATN-BP catalysts in this study was higher than those of previously reported Pd-and Pt-based EOR catalysts, including the open-mouthed, yolkshell (OM-YS) Au@AgPd, [38] Pd 40 Ni 43 P 17 , [4] Pd 83 Ni 17 hollow nanospheres (HNS) aerogel, [39] Pd-Pt-Ag nanosheets, [40] Pd@ CoP nanosheets (NSs)/carbon fiber cloth (CFC), [41] Pd 7 /Ru 1 , [42] Pd 68 /Cu 32 , [43] PdCo nanotube arrays (NTAs)/CFC, [44] Fe-PdFe 2 O 3 (3:5)/MWNTs, [45] Pd/B, N-codoped graphene nanoribbons (BN-GNRs), [46] Au@Pd core-shell nanorods [47] and ternary NiAuPt nanoparticles on reduced graphene oxide (rGO) nanosheets (Ni 40 Au 33 Pt 27 -NGs) [48] catalysts shown in Figure 8a. Because of the high synergistic interaction between the Pd NPs and ATN-BP and the structural contribution, the obtained Pd/ATN-BP catalyst shows relatively high mass activity for the EOR.…”

Electrochemical behavior of electrodeposited Pd and PdNi coatings for the ethanol oxidation reaction in alkaline solution

“…Examined parameters of EOR such as onset potential reaction and long-term stability show that among a series of graphene (G)-supported Ni x Pd 100−x binary alloyed catalysts, Ni 50 Pd 50 /G catalyst exhibits 60 mV lower onset potential compare to Ni 0 Pd 100 /G catalysts and current density approximately 8, 4, and 1.7 times superior than that of Ni 75 Pd 25 , Ni 0 Pd 100 /G, and Ni 25 Pd 75 /G catalysts, respectively [6]. The mass activity of the Pd 83 Ni 17 hollow nanospheres aerogel is 5.6-fold higher than that of the commercial Pd/C catalyst [14] while the mass activity of porous bimetallic PdNi catalyst is 3.5 times higher compared to the commercial Pd/C [15]. It is revealed that the onset potential is 80 mV lower and the peak current is about 3 times higher for ethanol oxidation using multi-walled carbon nanotubes (MWCNT) catalysts with Pd 1 Ni 1.5 compared to those of Pd/MWCNTs due to the small particle size and high crystallinity of binary catalyst [16] although it can be found that binary Pd 3.7 Ni 1 nanocatalyst with ultra-low loading of metals immobilized on MWCNT exhibits anodic current density over 11 times higher than on the Pd/MWCNT [17].…”

Nanostructuring Noble Metals as Unsupported Electrocatalysts for Polymer Electrolyte Fuel Cells

“…Recently, PdNi hollow nanospheres (HNSs) were employed as NBBs to fabricate a hierarchical aerogel with a well-defined 3D necklace-like network structure (Figure 4a-c). [41] The hollow cavity distributed throughout the networks could further be identified by a distinct peak (at ca. 22 nm) in the pore size distribution analysis (Figure 3f).…”

“…[25,26,[38][39][40] Linking aerogel research and nanotechnology, hierarchical aerogels with primary and secondary pore structures, built from shapeengineered NPs, have also been reported in the form of either hollow shell or dendritic particles. [41][42][43] As illustrated in Figure 1, the general synthesis of noble metal aerogels via the sol-gel process consists of three steps: i) the synthesis of nano-sized building blocks (NBBs); ii) the gelation of the NBBs into hydrogels (plus shape-control of the hydrogel) and iii) the supercritical drying of the hydrogel to yield an aerogel. These three strategies are outlined in different colors in paths I (B1-H1-A1), II (B1-H1-H2-A2) and III (B1-B2-H3-A3) of Figure 1.…”

“…As shown in Figure 1, this sub-structure can be obtained either by tailoring the hydrogel via strategy II (B1-H1-H2-A2) [43] or engineering the NBBs via strategy III (B1-B2-H3-A3). [41] At present, the research on metallic hierarchical aerogels prepared by manipulation of the NBBs is still in its infancy and lags far behind the abundance of colloidal metallic nanoarchitectures. [48] This may be ascribed to the frequent requirement of strong stabilizers for the shape-control of the metallic NPs, which is extremely detrimental to the subsequent gelation/destabilization of these colloids.…”