Exciting catalytic properties have recently emerged from two dimensional (2D) materials, including defect-laden graphene, metal dichalcogenides and hexagonal boron nitride (h-BN). Defects, particularly point vacancies are expected to play an important role in the reactions. To investigate the mechanistic pathways experimentally, properties beyond morphology have to be quantified in the vicinity of the defects, which calls for high lateral resolution and high sensitivity imaging and spectroscopy. However, the lack of experimental tool with sufficient spatio-temporal resolution hinders the direct study of the defect formation and kinetics of reaction. In this work, introducing defects in h-BN through ball milling, heat treatment and light is discussed. The nature of the defects introduced in the flakes is assessed, together with the catalytic performance of defect-laden h-BN. Functional atomic force microscopy (AFM) characterization reveals the structural, mechanical, electrical and chemical properties changes taking place at selected defect sites. The composition of the molecules formed on the active defects is evaluated by time of flight-secondary ions mass spectrometry (ToF-SIMS). Finally, the kinetics of oxygen and CO2 binding on defect sites is monitored under controlled environment to reach a better understanding of the mechanisms of catalysis of the material. The study constitutes a new experimental approach aiming to bridge the gap between molecular-level theoretical modelling and reactor-scale studies of h-BN for catalysis.

Evaluating the mechanisms of catalysis of defect laden h-BN at the micro- and nano-scales

2019 Spring National Meeting

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