Microwave assisted synthesis of carbon dots in ionic liquid as metal free catalyst for highly selective production of hydrogen peroxide

Nanometer scale doped carbon dots (CDs) were prepared using the microwave assisted method in the presence of bio-based materials and ionic liquid (1-ethyl-3-methylimidazolium ethylsulfate). First, glutamine and glucose in ionic liquid were used as carbon and nitrogen source. The surface characterizations confirm the formation of N-doped carbon dots with the presence of imidazolium and ionic liquid anion at the extreme surface. Next to that, CDs were generated in the absence of glutamine while using the ionic liquid as source of nitrogen. The TEM and surface analysis confirm the formation of nanoscale N-doped carbon dots. Furthermore, the catalytic activity of the generated CDs towards the oxygen reduction were investigated. As a result, both CDs materials exhibit a pronounced electrocatalytic activity with a prevalent 2 electron pathway leading to the formation of hydrogen peroxide. More interestingly, the CDs generated in the presence of glucose and ionic liquid display a selective 2 electron reduction of O-2, with H2O2 production higher than 90% for a potential range up to 0.8 V (from 0.6 V to -0.2 V vs RHE). (c) 2018 Elsevier Ltd. All rights reserved.