In a study published in the Chemical Engineering Journal, three-dimensional extremely thin lotus-shaped PdCu nanosheets (NSs) with enhanced photoelectrocatalytic abilities suitable for liquid fuel cells were developed.
Study: Advanced Plasmon-driven ethylene glycol oxidation over 3D ultrathin Lotus-like PdCu nanosheets. Image Credit: jaboo2foto/Shutterstock.com
Towards the Best Approach for Electrocatalysis
Direct alcohol fuel cells (DAFCs) are extremely effective energy converting devices that have abundant supplies, good energy storage, and minimal toxicity.
DAFCs have been used to ease the ongoing energy shortage; however, the slow kinetics of anode oxidation processes reduce their appeal.
Owing to the increased atomic usage of the precious metal Pd, Pd and Pd-based nanoparticles have been investigated as excellent electrocatalytic materials for the improvement of alcohol oxidation reactions (AORs).
Even so, some intermediates, such as COads, get quickly adsorbed to the exterior of Pd-based electrocatalysts, leading to drastic catalysis activity degradation.
Numerous endeavors have been dedicated to discovering dependable electrocatalysts with high performance and stability. Sunlight has lately been combined with energy converting devices to aid in the transformation of chemical to electrical energy.
To enhance alcohol oxidation, it is critical to build Pd-based catalysts that are highly sensitive to visible light. Namely, integrating sunlight with electrocatalysis creates exceptional photoelectrocatalysts capturing solar power to boost AORs.
How the SPR Effect Enhances AORs of Pd
The most commonly employed photocatalysts in existing literature are essentially semiconducting substances with small band gaps, although several plasma metals (mostly Au and Ag) also exhibit remarkable photovoltaic response capabilities due to their distinctive surface plasmon resonance (SPR) phenomenon.
SPR is the cumulative oscillations of outer electrons created when the photoelectrons' vibrational frequency synchronizes with the electrons on the surface of the noble metal.
Nonradiative decaying, being a key energy dissipating route of SPR, creates hot electrons that mostly get transferred to surrounding electron receivers and are used in subsequent chemical processes.
Using this very principle, by alloying Pd with plasma metals, several heated electrons may be transmitted to Pd, modifying its electronic framework and increasing its capacity to oxidize alcohols.
Copper is a Suitable Alternative to Gold and Silver
In previous similar studies, gold (Au) and silver (Ag) have been shown to have excellent photoelectric responsiveness to AORs, but their widespread use is hampered by their expensive price and limited resources.
Instead, owing to the outstanding SPR phenomenon, copper (Cu), a metal in the region of Au and Ag, has been discovered to have a behavior similar to their photoelectric reaction to AORs. Moreover, owing to their synergized effect, Cu shows outstanding catalysis promotion in the PdCu alloy, and the favorable adsorption tendency of COads on Cu nanostructures is advantageous for enhancing Pd's anti-poisoning capacity.
Factors Affecting the SPR Effect
Recent studies have shown that the shape of nanoparticles has a significant impact on the SPR of plasma metals.
Due to their high order and stability, 3D structures created by self-assembly of 2D extremely thin nanosheets can open up numerous active spots and provide ample mass/electron dispersion pathways and have thereby been demonstrated to be appealing nanomaterials in electrocatalysis. Additionally, the SPR effect is strongly influenced by the chemical makeup of the nanomaterials, which dictates the amount of catalytically active spots.
In this study, a series of PdCu nanosheets with controlled chemical makeup was successfully fabricated using a simple co-reduction approach. The growth process was discovered using time-tracking tests, and subsequent contrast studies showed the ideal response conditions to the exact structural control.
The electrochemical studies proved the products' better electrocatalysis capability to EGOR. The PdCu-2 nanosheets exhibited substantially enhanced mass activity and specific activity, as well as the maximum long-term stability owing to the extremely thin 3D nanosheet architecture, adjusted chemical makeup, and changed electronic framework of Pd.
More remarkably, the photoelectric reaction capacity of the adjusted PdCu-2 nanosheets was greatly improved due to the remarkable SPR phenomenon of Cu with visible light illumination. This research developed enhanced plasmon-driven photoelectrocatalysts for EGOR, which may give a simple technique for designing potential photoelectrocatalytic materials for DAFCs.
Zhang, K., Wang, C., You, H., Zou, B., Guo, S., Li, S., and Du, Y. (2022). Advanced Plasmon-driven Ethylene Glycol Oxidation over 3D Ultrathin Lotus-like PdCu Nanosheets. Chemical Engineering Journal. Available at: https://www.sciencedirect.com/science/article/pii/S1385894722011664?via%3Dihub