Ethylene Glycol Electrooxidation Based on Pentangle-Like PtCu Nanocatalysts

Selective Ethylene Glycol Oxidation to Formate on Nickel Selenide with Simultaneous Evolution of Hydrogen

There is an urgent need for cost-effective strategies to produce hydrogen from renewable net-zero carbon sources using renewable energies. In this context, the electrochemical hydrogen evolution reaction can be boosted by replacing the oxygen evolution reaction with the oxidation of small organic molecules, such as ethylene glycol (EG). EG is a particularly interesting organic liquid with two hydroxyl groups that can be transformed into a variety of C1 and C2 chemicals, depending on the catalyst and reaction conditions. Here, a catalyst is demonstrated for the selective EG oxidation reaction (EGOR) to formate on nickel selenide. The catalyst nanoparticle (NP) morphology and crystallographic phase are tuned to maximize its performance. The optimized NiS electrocatalyst requires just 1.395 V to drive a current density of 50 mA cm^-2 in 1 m potassium hydroxide (KOH) and 1 m EG. A combination of in situ electrochemical infrared absorption spectroscopy (IRAS) to monitor the electrocatalytic process and ex situ analysis of the electrolyte composition shows the main EGOR product is formate, with a Faradaic efficiency above 80%. Additionally, C2 chemicals such as glycolate and oxalate are detected and quantified as minor products. Density functional theory (DFT) calculations of the reaction process show the glycol-to-oxalate pathway to be favored via the glycolate formation, where the CC bond is broken and further electro-oxidized to formate.

Hierarchical branched platinum-copper tripods as highly active and stable catalysts

Designing and manipulating the structure of nanomaterials can efficiently tailor their catalytic properties, enabling the promotion of both their activity and stability. We herein report the shape-controlled synthesis of advanced Pt-Cu hierarchical tripod nanocrystals (HTNCs) by controlling the amount of KI and reaction time. The as-prepared nanocrystals (NCs) look like a typical tripod on the whole, consisting of similar branch structural units. In addition, the structure of the HTNCs could also be obtained with a narrow Pt/Cu feeding ratio. Owing to the unique HTNC structure and exposed high-index facets, as well as probable electronic effects between Cu and Pt, the as-obtained Pt-Cu HTNCs can exhibit greatly enhanced electrocatalytic activity toward ethylene glycol oxidation reaction (EGOR) and glycerol oxidation (GOR), which are 5.1 and 6.5 times higher in mass activity, as well as 5.6 and 7.3 times higher in specific activity relative to commercial Pt/C, showing that they are a class of promising electrocatalyst for fuel cells. This work presents huge opportunities for optimizing the electrocatalytic oxidation reaction by designing the structure of nanocatalysts.