Nanoscale Engineering of Building Blocks to Synthesize a Three-Dimensional Architecture of Pd Aerogel as a Robust Self-Supporting Catalyst toward Ethanol Electrooxidation

Abstract

Although plenty of research studies have extensively focused on the synthesis of electrocatalysts with diverse methods, the synthesis of a high-performance electrocatalyst by a green and efficient method has still remained a vital problem that can seriously hamper the commercialization of fuel cell technology. Metallic aerogels recently appeared as a promising state-of-the-art class of self-supported architecture electrocatalyst materials because of their great electrocatalytic activity and enhanced stability for different electrochemical reactions. By taking advantage of the nanostructure engineering and new chemical reduction reaction, a novel, simple, eco-friendly, and surfactant-free procedure for the fabrication of self-assembled Pd aerogel is presented in this paper that uses the spontaneous one-step gelation process for synthesis. In contrast with other methods, our new method presents some advantages, such as being eco-friendly, simple, and having rapid synthesis. A palladium alcogel is prepared by reducing H2PdCl4 in ethanol utilizing C2H5OH/NaOH as a green reductant agent in a short time for the first time, and in the following step the palladium aerogel is obtained by supercritical drying. An extraordinary 3D nanonetwork of the Pd aerogel with large porosity is then affirmed using HRTEM, FESEM, XRD, EDX, and BET methods. Due to the profuse open interconnected pores and large inner surface areas, the Pd aerogel not only showed highly boosted electrocatalytic activity toward the ethanol oxidation reaction but also depicted much higher stability, durability, and mass activity in alkaline electrolyte than Pd/C. It is believed that the Pd aerogel prepared via a straightforward approach is an advanced candidate for applications in electrocatalysis for direct alcohol fuel cells and can create a great window of opportunity for different energy-related systems.

Bimetallic Pd–Co Aerogel Three-Dimensional Architecture: Developing Self-Assembled Materials for Advanced Ethanol Oxidation

“…As illustrated, electrocatalysis of EtOH generates two strong peaks in the forward and reverse sweeps. The first peaks were generated because of the decomposition of EtOH molecules at the surface of four samples. ,− These interactions not only delivered the high current density but also produced the carbonaceous intermediates . Hence, other peaks appeared in backward scans because of the elimination of produced carbonaceous intermediates.…”

“…Hence, other peaks appeared in backward scans because of the elimination of produced carbonaceous intermediates. Subsequently, it can be logically concluded that the current density ratio generated in the forward ( J f ) to reverse ( J b ) scans can be used as a reliable parameter to evaluate the power of an electrocatalyst. ,− By comparing the achieved plots, the Pd 92 Co 8 aerogel ( J f / J b = 1.17), Pd 95 Co 5 aerogel ( J f / J b = 1.13), and Pd 89 Co 11 aerogel ( J f / J b = 0.96) reveal a stronger tolerance to poisoning relative to Pd/C ( J f / J b = 0.6). Additionally, the decomposition reaction of EtOH for Pd 92 Co 8 aerogel (−0.548 V), Pd 95 Co 5 aerogel (−0.538 V), and Pd 89 Co 11 aerogel (−0.532 V) started at a more negative potential in comparison to Pd/C (−0.460 V), corroborating the improved kinetics for these resultant 3D superstructures. , Moreover, the Pd 92 Co 8 aerogel, Pd 95 Co 5 aerogel, Pd 89 Co 11 aerogel, and Pd/C generated the mass activity of 4302.1, 3380.9, 2135.1, and 1007.9 mA/mg Pd .…”

Exposing an Environmentally Friendly Gelation Strategy to Fabricate Modern Three-Dimensional M–Ag (M = Pt and Pd) Aerogels with Excellent Green Energy Generation

“…These shoulders were generated because of the decomposing CH 3 CH 2 OH molecules on the surface of Pt–Ag and Pd–Ag aerogels. The interaction of CH 3 CH 2 OH molecules with the surface of both aerogels not only provides high current density but also generates some carbonaceous intermediates. − Hence, these incomplete interactions lead to the appearance of other distinct shoulders during backward scans due to the decomposition of generated intermediates. − Therefore, a strong electrocatalyst should have a high forward/backward ( J f / J b ) ratio. − Measurement of this ratio ( J f / J b ) gives values of 0.6, 2.67, and 1.38 for Pd/C, Pt–Ag aerogel, and Pd–Ag aerogel, respectively. This indicates that both aerogels have greater tolerance to poisoning relative to Pd/C.…”

“…This is due to the fact that Pd is more active in an alkaline electrolyte relative to Pt. Furthermore, the mass activities relevant to Pt and Pd-based electrocatalysts for the cleavage of CH 3 CH 2 OH molecules were compared with those of Pt–Ag aerogel − (Figure c) and Pd–Ag aerogel ,,− (Figure d). As illustrated, Pt–Ag and Pd–Ag aerogels provide higher mass activities for the decomposition of CH 3 CH 2 OH molecules relative to other electrocatalysts.…”

B,N-Doped PdRu Aerogels as High-Performance Peroxidase Mimics for Sensitive Detection of Glucose

“…The single Pd-based catalyst has the drawback of catalytic activity loss caused by the aggregation of Pd particles. As reported by Yi et al before, alloying Pd with Ru can perform much higher catalytic activity by adjusting the electronic structure of materials through geometric and ligand effects. − To develop noble metal alloy aerogels with better activity, some new strategies should be explored.…”