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Single-atom catalysts (SACs) have emerged as a hot research topic in recently years, and have been intensively investigated for energy storage and conversion applications. Significant advances in the synthesis of SACs have been achieved through enormous efforts in this area, however, their application is hindered by the low active site loading and poor long-term stability. In contrast with other methods, atomization, in which the SACs are synthesized from transformation of the nanoparticles to atomic sites, is a very attractive and innovative top-down approach to achieve high-density supported active sites with outstanding stability. However, limited attention has been paid to this area, despite the significant advances achieved in the past two years. In this short review, we discuss in detail the latest advances in atomization approaches for the synthesis of SACs and highlight the associated advantages and opportunities.

Microporous layer (MPL) is a vital component for proton-exchange membrane fuel cells (PEMFCs) to improve the cell performance. However, the conventional preparation of MPL, involving the mixing of carbon black with hydrophobic agent polytetrafluoroethylene (PTFE), followed by high-temperature annealing, is often complicated and costly. Herein, we present a facile and low-cost method to fabricate the MPL by functionalization of carbon black via covalent bonding with hydrophobic agent. Upon chemical grafting with fluoroalkylsilane (FAS-17), the water contact angle of carbon black is increased from 66.4 to 150.4°, resulting in superhydrophobicity. The MPL prepared with the resultant superhydrophobic carbon endows the PEMFC with enhanced gas and water permeability and hereby improved electrochemical performance over traditional MPL, and a maximum power density of 1211 mW cm −2 for the PEMFC can be obtained. This work offers a feasible strategy to construct an efficient MPL for the PEMFC via a chemical grafting approach.

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