Multiscale design for high-performance glycolic acid electro-synthesis cell: Preparation of nanoscale-IrO2-applied Ti anode and optimization of cell assembling

Hou

et al. 2023

ChemCatChem

Reducing oxalic acid to glycolic acid electrochemically remains a significant challenge due to the high overpotential and low selectivity and stability. This study uses mesoporous TiO2 spheres of anatase phase as catalysts to reduce oxalic acid to glycolic acid with low overpotential. The maximum Faradaic efficiency of glycolic acid reaches 73.9 % at −0.5 V vs RHE. The mesoporous structure not only increases the specific surface area, but also limits the escape of intermediate glyoxalic acid from the catalyst surface due to the space‐limiting effect of the mesoporous channel, such that oxalic acid can be deeply reduced to glycolic acid. Moreover, a mechanism for oxalic acid reduction is proposed, and the Ti3+/Ti4+ redox pair plays an important role in the reduction of oxalic acid.

Section: Resultsmentioning

confidence: 54%

Selective Electroreduction of Oxalic Acid to Glycolic Acid by Mesoporous TiO₂ Spheres

Hou

et al. 2023

ChemCatChem

“…Compared to the literature, GaSnO x /C-coated CFP showed exceptional FE GC and j GC . At a similar current density, FE GC using TiO 2 /Ti mesh (TiO 2 /Ti-M) or TiO 2 /Ti felt (TiO 2 /Ti-F) was between 40 and 80% . In another work, the FE GC at a potential of −1.1 V vs Ag/AgCl using hydrothermally synthesized Ti (TiNT-HS) was 60.8% with a current density of −2.3 mA cm –2 (Table S1).…”

Section: Resultsmentioning

confidence: 99%

“…Oxalic acid (OA) is a C 2 product from CO 2 electroreduction with high selectivity and can be further reduced to value-added products such as glycine, glyoxylic acid (GX), and glycolic acid (GC). − GX and GC are 2-electron and 4-electron reduction products of OA as well as feedstocks of various chemicals such as glycine and polymer materials. − Conventional methods for GX and GC production include glyoxal oxidation, ozone oxidation, and formaldehyde carbonylation, which require extra energy input and multiple procedures. Electroreduction of OA offers the sustainable production of green GX and GC, not only being environmentally friendly but also saving cost by simplifying the process. ,,− …”

Section: Introductionmentioning

confidence: 99%

Temperature-Dependent Electrosynthesis of C₂Oxygenates from Oxalic Acid Using Gallium Tin Oxides

Hou

et al. 2023

ACS Catal.

The electrosynthesis of multi-carbon chemicals such as glyoxylic acid (GX) and glycolic acid (GC) from oxalic acid (OA) offers a feasible pathway to achieve sustainable chemical production, especially when coupled with the electroreduction of CO2 to form OA. Here, we demonstrate a series of gallium tin oxide catalysts for selective, controlled OA electroreduction to GX and GC in acidic media. The product distribution can be tuned by changing the reaction temperatures. At room temperature using the GaSnO x /C catalyst, GX can be obtained with a GX Faradaic efficiency (FEGX) of 92.7% at −0.7 V vs RHE and a GX current density (j GX) of −100.2 mA cm–2. At a raised temperature of 80 °C using the GaSnO x /C catalyst, a GC Faradaic efficiency (FEGC) of 91.7% at −0.8 V vs RHE can be obtained. The accelerated OA electroreduction results from the Ga/Sn synergy in the catalysts. A proper Ga/Sn ratio not only enriches OA adsorption and enhances surface binding of intermediates, but also ensures catalyst stability in acidic media.

“…In a previous report, a flow-type PEAEC was utilized for the evaluation of the yield and selectivity of the electroreduction of OX. , In this study, we designed a self-standing electrode film composed of a current collecting layer and electrocatalyst layer, which is soft and thus convenient for assembling the membrane electrode assembly (see Figure a). The MWNT/PyPBI/TiO 2 with an anatase TiO 2 content of 18 wt % was used as the electrocatalyst.…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, the theoretical capacity of the GC solution produced by the electrochemical reduction of a saturated aqueous solution of OX (∼3.89 M) reached about 417 Ah l −1 , which is 190 times higher than that of hydrogen gas (2.2 Ah l −1 (SATP)). 15,17 These advantages make the OX/GC redox-based energy cycle attractive for noncarbon emission energy storage.…”

Section: Introductionmentioning

confidence: 99%

Wrapping Multiwalled Carbon Nanotubes with Anatase Titanium Oxide for the Electrosynthesis of Glycolic Acid

Yang

Tao

et al. 2019

ACS Appl. Nano Mater.

Self Cite

The construction of an efficient electrocatalyst is of significant importance for electrochemical devices. In this study, a facile preparation method is developed to wrap pristine multiwalled carbon nanotubes (MWNTs) by an anatase TiO2 layer with the assistance of pyridine-based polybenzimidazole (PyPBI) The factors dominating the morphology of the obtained MWNT/PyPBY/TiO2 products, involving the employment of PyPBI and the post-treatment method, are investigated in detail. Furthermore, a self-standing electrode film is prepared via a filtration route. The electrode film is composed of a MWNT/PyPBI/TiO2 catalyst layer and a MWNT current collecting layer. The resultant electrocatalysts and electrode film with the MWNT/PyPBI/TiO2 catalyst are evaluated for the electroreduction of oxalic acid (OX) to glycolic acid (GC). By using the optimized electrode film with the MWNT/PyPBI/TiO2 catalyst, the conversion rate of OX and the selectivity of GC reach 51.2% and 38.7%, respectively.