Noble Metal Based Electrocatalysts for Alcohol Oxidation Reactions in Alkaline Media

Abstract

Alkaline direct alcohol fuel cells (ADAFCs) represent an attractive alternative to hydrogen fuel cells for the more convenient storage, transportation, and lower cost of alcohols (e.g., methanol and ethanol) when compared with compressed hydrogen. However, the anode alcohol oxidation reaction (AOR) is generally plagued with high overpotential and sluggish kinetics, and often requires noble metal-based electrocatalysts to accelerate the reaction kinetics. To this end, the development of efficient AOR electrocatalysts with high mass activity (MA), high durability, high Faradaic efficiency (FE), and low overpotential is central for realizing practical ADAFCs. Here, in this minireview, a brief introduction of the fundamental challenges associated with AOR in alkaline electrolyte, the key performance metrics, and the evaluation protocols for benchmarking AOR electrocatalysts are presented, followed by a summary of the recent advances in the noble-metal based AOR electrocatalysts (e.g., Pt, Pd, and Rh) with an emphasis on the design criteria for improving the specific activity and electrochemical surface area to ultimately deliver high MA while at the same time ensuring long term durability. The strategies to enhance FE and lower overpotential will also be discussed. Last, it is concluded with a brief perspective on the key challenges and future opportunities.

Pd/Ni-metal–organic framework-derived porous carbon nanosheets for efficient CO oxidation over a wide pH range

“…Various efforts were dedicated to solving these barriers lied in tailoring the size, shape, and lowering composition of Pd nanocrystals and their supports, thereby reducing the cost of the catalyst. [14][15][16][17][18][19][20][21][22][23] Altering the d-band center of Pd by second metals allows self-production of reactive oxygenated species (i.e., •OH radicals), which accelerate the CO oxidation kinetics and tolerate the adsorption of intermediates. [14][15][16][17][18][19][20][21] For example, Pd nanodendrites enhanced the CO oxidation mass activity (58 mA/mg Pd ) by 1.9 folds than commercial Pd/C.…”

Recent development and challenges in fuel cells and water electrolyzer reactions: an overview

“…The synergetic effect is mainly determined by the following three kinds of effects: (i) the ligand effect: the different composition of the core and shell leads to electron transfer and a change in the band structure; (ii) the strain effect: the tension or compression of the noble metal shell lattice causes a change in the surface adsorption energy; (iii) the geometric effect: the different three-dimensional structure of the surface atoms can affect the electrochemical properties. 90 Through the combination of these effects and theoretical calculation, core–shell structured noble metal-based nanomaterials with better ORR properties can be reasonably designed and prepared. 91 …”

Hydrogel Nanocomposite-Derived Nickel Nanoparticles/Porous Carbon Frameworks as Non-Precious and Effective Electrocatalysts for Methanol Oxidation

“…Materials based on noble metals as the anode electrodes are typically utilized, despite their scarcity and high cost. Massive efforts have been made to replace noble metal-based electrocatalysts with low-cost and more efficient materials such as non-precious transition metals [ 8 , 9 ]. Among the transition metals used for this purpose, Ni [ 10 , 11 ], Mn [ 12 ], Mo [ 13 ], Cu [ 14 ], and Co [ 15 , 16 ] are the most common.…”