Glycerol, a byproduct of biodiesel production, is an industrial waste because of its excess yield. Electrooxidation of glycerol is a promising way to utilize glycerol through harvesting electric energy as fuels in a fuel cell or hydrogen as sacrificial agent in electrolysis cellwhile generating valuable chemicals. Here, we report a detailed mechanistic study of the glycerol electrooxidation reaction (GOR) on a series of Pt/C, Pt x Ru y /C, and Pt x Rh y /C nanocatalysts synthesized by NaBH 4 reduction. The EC cyclic voltammetry characterization indicates that alloying Ru with Pt greatly enhanced the GOR activity, especially at low potential, but not as much with alloying Rh, as compared with Pt/C. In situ FTIR and 13 C NMR spectroscopies were used to investigate the GOR mechanism at a molecular level. The results demonstrate that the selectivity of products depends on the type of catalysts and the oxidation potential. Although both PtRu/C and PtRh/C could accelerate the oxygen insertion reactions that led to higher selectivity of carboxylic acids, tartronic acid was more favored at high potential on the PtRh/C surface.

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With the strength of liquid nuclear magnetic resonance (NMR) to noninvasively and specifically realize the structural elucidation and quantitative analysis of small organic molecules, in principle, liquid in situ electrochemical-NMR (EC-NMR) possesses great advantages for detecting dissolved species during the electrochemical process. However, the intrinsic incompatibilities between the coupling techniques as well as the sophisticated setups modification still limit the applications toward a wide range. To overcome these bottlenecks, herein we propose an easy-to-construct design with good compatibility and presenting improved electrochemical and NMR performances. As proof of concept, model experiments of alcohol electrooxidation were performed to confirm the capacity of this device for liquid in situ EC-NMR study. The temporal evolution of both the product and the current distributions can be reliably recorded to aid mechanistic and kinetic understanding of electrocatalysis. The depiction of the selective electrooxidation reveals the surface structure−catalytic functionality. This work demonstrates the universality and effectivity of the proposed platform to develop the liquid in situ EC-NMR technique as a useful tool for the dynamic analysis of electrochemical processes at a molecular level.

We report the design and the performance of a two-chamber thin-layer electrochemical device for in situ potential-dependent liquid NMR measurement. Liquid NMR spectra, simultaneously recorded with cyclic voltammetry (CV), have been obtained to reveal molecular changes with potentials scanning. As a proof of concept, redox properties of 1,4-benzoquinone based systems have been investigated, and a π dimerization has been identified by combining both in situ and ex situ NMR analyses. This work provides a new approach for spectroelectrochemistry, which will contribute to developing electrochemical NMR (EC-NMR) as an important tool for the analysis of electrochemical process at a molecular level.

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