Non-precious metal catalysts on low dimensional support are promising materials to replace Pt based catalysts for a wide range of energy-related electrochemical reactions due to their low cost and high natural abundance.¹ Low dimensional support materials such as carbon nanotubes² and graphene³have been explored as next generation support materials among the various types of support materials owing to their high electrical conductivity and excellent durability. Many effort has been made in synthesizing low dimensional materials decorated with metals using methods such as thermal treatment, photochemical, and wet chemical synthetic routes.³Electrochemical synthesis is one of the most straightforward and versatile method to generate supported non-precious metal catalysts. Further improving the synthesis and design of supported Cu nanocatalysts requires a good mechanistic understanding of deposition process under typical electrochemical conditions so as to understand the interplay of kinetic and thermodynamic phenomena such as the dimensionality of support materials, external electrochemical parameters, and effects of doping.
Here, we demonstrate the use of operando liquid phase electron microscopy with high spatial and temporal resolution to uncover detailed mechanisms associated with these promising supported electrocatalysts low dimensional materials decorated with non-precious metal nanocatalysts during electrochemical deposition in typical acidic electrolytes . We first discuss the Cu electrodeposition onto low dimensional support materials, i.e., carbon nanotubes and graphene, under cyclic voltammetry conditions. Next, we investigate the deposition kinetics using different external parameters and how they affect the size distribution of the electrochemically grown metal islands on low dimensional support materials. We finally discuss the effect of nitrogen doping employed to engineer the support material and compare its outcome to the non-doped analogue. Observing the nanocatalyst formation process on these engineered and non engineered supports can allow us to assess the favorable doping sites towards the realization of functional metal 1D/2D materials systems that will be beneficial not only for fuel cell catalysts but also for other heterogeneous catalysts and optoelectronic designs.

Shu Fen Tan

Nanyang Technological University

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