Efficient Electrocatalytic Ethanol Oxidation Using Lanthanum Nickel Oxide Nanoparticles Anchored on Graphite Surface

Ethanol oxidation reaction (EOR) using non-precious metal oxide-based nanostructures is important in the current energy landscape. However, the sluggish kinetics is one of the major bottleneck for EOR. Therefore, this work deals with the synthesis of lanthanum nickel oxide (LNO) via a facile coprecipitation method. The microstructural study confirms the formation of nanoparticles of size 40-70 nm. Furthermore, LNO NPs were deposited onto the graphite surface to evaluate their oxygen evolution reaction (OER) and EOR in an alkaline media. OER study shows an overpotential of 410 mV compared to graphite (740 mV). However, during EOR, the cyclic voltammetry (CV) shows the forward and backward oxidation peaks at 1.51 V, and the potential required to reach 10 mA/cm² decreases to 1.41 V with a high current density of ~80 mA/cm² at 2 V in the presence of ethanol in comparison to OER electrolysis in bare KOH (1.69 V). A significant reduction of ~280 mV in the required potential is observed compared to catalysis in bare KOH. The integration of LNO NPs with the graphite surface results in enhanced ethanol oxidation activity due to improved charge transport and interfacial synergy. Further, the catalytic insights have been discussed in detail using ECSA, EIS, and contact angle measurements.