Ultrathin one-dimensional platinum-cobalt nanowires as efficient catalysts for the glycerol oxidation reaction

Improving Glycerol Electrooxidation Performance on Nanocubic PtCo Catalysts

As glycerol (GLY) has emerged as a highly functional and cheap platform molecule and as an abundant biodiesel production byproduct, possible conversion methods have been investigated. One of the promising approaches is the glycerol electrooxidation (GEOR) on noble metal-based catalysts. Although noble metals, especially Pt, are generally very stable at different pH and highly selective toward three-carbon (C3) products, their electrocatalytic performance can be further improved by morphology tuning and alloying with non-noble metals like Co. In the present study, cubic PtxCo100-x (x = 100, 80, and 60) nanoparticles were investigated in an alkaline medium at 20 and 40 °C. The effect of the composition and reaction conditions on the selectivity of the GEOR toward C3 products like lactate and glycerate was studied, and the reaction mechanism was discussed. The highest mass activity was found for Pt80Co20, although when the specific activity, glycerol conversion, and GEOR selectivity were compared, Pt60Co40 was the superior catalyst overall. In general, all catalysts, even those that are Co-rich, exhibited a high C3 product selectivity up to 95% at 0.67 V vs RHE. The low applied potential of 0.67 V vs RHE at 40 °C facilitated lactate formation with selectivity up to 72%. At the same time, the glycerate formation with a selectivity of up to 40%, as well as C-C bond cleavage, was more favored at 0.87 V vs RHE.

Recent Achievements in Noble Metal Catalysts with Unique Nanostructures for Liquid Fuel Cells

In recent years, research efforts have been focused on the design and fabrication of highly efficient catalysts for liquid fuel cells, because the use of these cells is an important approach for alleviating environmental pollution and energy crises. However, the limitations of the catalytic performance of industrial Pt/C have strongly hindered the development of these fuel cells. The catalyst morphology has a strong impact on its performance; nanostructured catalysts are preferred as they offer large specific surface area and more exposed active centers. In view of this, many catalysts with unique structures have been synthesized in recent years, all of which show excellent catalytic performance characteristics. Despite these achievements, few efforts have been made to survey this field comprehensively. Herein, the recent advances in catalysts for liquid fuel cells are summarized, with a focus on noble metal catalysts with unique morphologies such as nanowires, nanosheets, and assembly structures. Their formation mechanisms are discussed critically. The relationship between the unique morphologies and excellent performance of these catalysts is also explored. This work may provide guidelines for the further development of liquid fuel cells.