Discerning structure property correlation towards the activation of small molecules

Abstract

newline This thesis deals with the physical transformation and chemical reactivity of graphene newlinebased materials on interaction with small sized molecules (H2O, CO2 and CO) and species such newlineas -OH, -NH2, -OSi(OH)4. For the activation of small molecules and from the perspective of newlineelectrocatalysis, the foremost important task is to understand the electrode surface [(doped) newlinegraphene/atomic clusters] and its interaction with the desired molecules (for example, CO2/CO) newlineunder perturbed conditions. Thus, in Chapter 3.1, we studied chemical reactivity pattern of newlinegraphene nanoflakes and its effect towards the adsorption of electrophilic/nucleophilic newlineintermediates. Furthermore, these conceptual-DFT based reactivity descriptors have been newlineexploited to provide the insights into the experimentally observed induction of curvature in newlinegraphene nanoflakes upon chemical functionalization (Chapter 3.2). These indices along with newlinespin/charge density, frontier molecular orbitals and binding energy, provided the insights newlinetowards the activation and reduction of CO2 on boron-doped graphene (Chapter 4.1). newlineMoreover, also elucidated are the mechanisms for the selective formation of formic acid in newlinepreference to CO and drawn correlation for the early onset of CO2 reduction over hydrogen newlineevolution (Chapter 4.1). We have identified the active sites based on these descriptors for the newlineadsorption (physisorption/chemisorption) of CO2 and stabilization of the important newlineintermediate (*COOH) over boron-doped graphene, leading to the selective reduction of CO2. newlineIn Chapter 5, we found with the aid of combined experimental and theoretical analysis, the newlinefeasible chemisorption of CO on boron-doped graphene under the applied bias. In addition, newlineexplained the formation of formate during CO reduction under alkaline conditions. Moreover, newlinewe also have discovered that the C-C bond is feasible electrocatalytically over boron-doped newlinegraphene at low overpotentials. The mechanism star