Sn-based chi-rGO/SnO2 Nanocomposite as an Efficient Electrocatalyst for CO2 Reduction to Formate

Abstract

Designing efficient and cost-effective electrocatalysts in simple ways is very important for energy efficiency. In this sense, nano-sized materials have been extensively utilized for the development of efficient electrodes for electrochemical CO2 reduction. In the present study, we have developed a Sn/chitosan-reduced graphene oxide (chi-rGO)/SnO(2 )composite electrode via only electrochemical techniques and tested it for electrochemical reduction of CO2 to formate. A bare Sn plate was modified with a reduced graphene oxide layer in the presence of chitosan to get a stable Sn/chi-rGO composite structure and to get more active sites, thus an efficient reduction process was performed. The surface of the Sn/chi-rGO composite was further modified by SnO2 nanoparticles via the potentiostatic electrodeposition method at a fixed applied potential of -0.6 V for varying periods. The calculated double-layer capacitance (Cdl) of the Sn/chi-rGO/SnO2 electrode was about 80 times larger than the bare Sn plate implying that the coexistence of SnO2 nanoparticles on the (chi-rGO) structure enhanced the electrochemically active sites. The maximum Faradaic efficiency was recorded as 88 % towards the production of formate at an average current density of -7.36 mAcm(-2 )at -1.8 V. Electrochemical measurements and the stability test revealed that the resultant Sn/chi-rGO/SnO2 composite structure behaves as a potential electrode material for efficient CO2 conversion to formate.The study presents a simple and low-cost electrode preparation procedure including only electrochemical techniques which can be conducted within a very short time and without using extra energy and chemicals/additives.