Millisecond-scale rapid synthesis of single-atom catalysts-stabilized carbon nano-onion for hydrogen evolution reaction

Abstract

The unique properties of carbon nano-onions (CNOs), including their nanometer-scale surface curvature and the ability to be functionally modified, have attracted significant attention in energy and environmental applications. However, conventional methods for synthesizing CNOs and subsequent functionalization treatments are associated with drawbacks such as prolonged processing times and high energy consumption. In order to overcome these challenges, we propose an innovative approach called intense pulsed light (IPL)-based photothermal annealing that enables the rapid synthesis of CNOs while simultaneously functionalizing their surfaces with single-atom catalysts (SACs). Our IPL process enables the attainment of temperatures up to 3030 K within a remarkably short duration of 1.4 ms (equivalent to a heating rate of 2.2 × 10⁶ K s⁻¹). Additionally, we demonstrate the broad applicability of SACs functionalization on the outer surface of CNOs by employing eight different transition metal elements (Pt, Ir, Ru, Cr, Cu, Co, Ni, and Fe). Among them, Pt SACs-functionalized CNOs exhibit outstanding catalytic performance in the hydrogen evolution reaction. These catalysts demonstrate an overpotential of only 13.9 mV at 10 mA cm⁻² and a Tafel slope of 52 mV dec⁻¹, thereby highlighting their remarkable efficiency and effectiveness.