Energy-Efficient Rational Designing of Multifunctional Nanocomposites by Preferential Anchoring of Metal Ions via Fermi Level Positioning of Carbon Nanostructures.

Despite the availability and dedicated studies on a variety of carbon nanostructures, amorphous carbon is still a preferred support for a wide range of commercially available metal catalysts. In order to shed some light on this, we carried out electroless deposition of metal nanoparticles on various carbon nanostructures such as amorphous carbon (a-C), carbon nanotubes (CNTs), and nitrogen-doped CNTs (NCNTs) under similar experimental conditions. The main objective is to elucidate the preferable deposition on a particular carbon nanostructure, if any, and understand the underlying mechanism. Experimental results unveil preferred electroless deposition of metal nanoparticles on a-C over CNTs and NCNTs. Notably, the deposition is nicely correlated with the position of the Fermi level ( E _F ) with respect to the M ^{n +} ↔ M ⁰ redox level ( E ₀ ). Remarkably, E _F is found to be in the following order NCNT > CNT > a-C and the smaller gap ( E ₀ - E _F ) favors the faster electron transfer, resulting in the preferential reduction of M ^{n +} , yielding finer nanoparticles on a-C. We believe that this approach can pave the way for designing noble metal-based carbon nanocomposites for a variety of applications, ranging from environmental redemption to electrochemical energy harvesting. As case studies, we have explored the nanocomposites for various catalytic activities and found them to be very competent with recently reported various state-of-the-art electrocatalysts and their commercial counterparts.