CeVO4 Nanosheets as Bifunctional Electrocatalysts for Glycerol Oxidation and Hydrogen Peroxide Sensing

Glycerol, a significant byproduct of biodiesel manufacturing, offers the potential for conversion into valuable substances such as formic acid (FA), glyceric acid (GLA), and glycolic acid (GCA). The selective oxidation of glycerol, especially into FA, is both economically crucial and technically challenging. While precious metals like gold (Au) and platinum (Pt) have conventionally served as catalysts, there is growing interest in nonprecious alternatives. In this context, we explored the use of complex metal oxide, cerium vanadate nanosheets (CeVO4 NS), as a catalyst for the electrochemical oxidation of glycerol to FA. The higher surface area (compared to the 3D structure) coupled with the redox-active nature and electric properties of CeVO4 NS facilitate the electrocatalytic performance. The glycerol oxidation with the CeVO4 NS electrocatalyst exhibited a highly selective formation of FA with a high Faradaic efficiency of 91.5%. The reaction is also kinetically more facile than competing reactions, and the performance is better than the reported catalysts. The mechanistic investigation revealed that the formation of FA involves GCA as an intermediate. Alternately, selective and efficient sensing of hydrogen peroxide (H2O2) is of paramount importance in industries for environmental monitoring and clinical uses. Owing to its beneficial structural and electronic features, the CeVO4 NS were also employed for electrochemical nonenzymatic H2O2 sensing. The CeVO4 NS exhibited high sensitivity (175 mu A mM(-1)<bold><middle dot></bold>cm(-1)) toward electrochemical H2O2 sensing with a detection limit of 5.6 mu M. Importantly, the CeVO4 NS sensor system is reusable and stable. The superior glycerol oxidation and H2O2 sensing performance establish the enormous potential of CeVO4 NS as a multifunctional material.