Fe-Doped Copolymer-Templated Nitrogen-Rich Carbon as a PGM-Free Fuel Cell Catalyst

Abstract

Platinum group metal-free (PGM-free) catalysts present a promising opportunity to make hydrogen fuel cells more affordable; however, issues with stability and electrochemical activity continue to hinder their application. Recent studies point to the availability of nitrogen and a controlled mesoporous structure as avenues of improvement. To address this need, copolymer-templated nitrogen-enriched carbon (CTNC) was used as the precursor to prepare PGM-free catalysts for the oxygen reduction reaction (ORR). By employing its rich nitrogen content and interconnected mesoporous structure, a significant amount of Fe–N–C-active sites were formed by co-annealing CTNC with FeSO4. The formed N/Fe co-doped nanocarbon (CTNC-Fe) catalyst exhibits good electrochemical activity with a half-wave potential of 0.781 V vs normal hydrogen electrode (NHE), a total surface area of 400 m2/g, and a power density of 180 mW/cm2. The block copolymer (BCP) was made by atom transfer radical polymerization (ATRP), which allows control and tunability of the block copolymer. This work opens new opportunities to improve the electrochemical activity and stability of PGM-free catalysts by controlled polymerization techniques that precisely tune the pore structure and maximize nitrogen content to improve the formation of active sites in the catalysts.

Chloride-Tolerant, Inexpensive Fe/N/C Catalysts for Desalination Fuel Cell Cathodes

“…Considering that Fe/N/C is a nonprecious catalyst, our results show for the first time that the cost/performance trade-off strongly favors Fe/N/C over Pt/C for desalination fuel cell applications. Given the richness of nonprecious metal catalysts investigated for classical fuel cell applications, − this work opens up the field of desalination fuel cells to similar investigations. In the future, through wider materials explorations and optimization, we believe that nonprecious metal catalysts may outperform Pt in desalination fuel cells.…”

Inverse Miniemulsion Enables the Continuous-Flow Synthesis of Controlled Ultra-High Molecular Weight Polymers

“…Since its discovery, reversible-deactivation radical polymerization (RDRP) has been leveraged to access a wide variety of polymers that can be applied in various fields from biomedicine to informatics. − The ability to precisely tune chemical and physical properties of macromolecules (e.g., molecular weight, architecture, functionality) has led to the deployment of RDRP for the synthesis of advanced materials across a wide range of size scales. − While predetermined molecular weights are a defining feature of RDRP methods, such as atom transfer radical polymerization (ATRP), nitroxide mediated polymerization (NMP), and reversible addition–fragmentation chain transfer (RAFT) polymerization, targeting molecular weights in excess of 10 6 g/mol is challenging and typically requires specialized reaction conditions, such as high pressure. − However, recent reports in RDRP have opened new synthetic pathways to access polymers of ultra-high chain length under mild reaction conditions . We recently demonstrated that long-wave ultraviolet (UV) irradiation (λ = 365 nm) of thiocarbonylthio compounds in the presence of vinyl monomers with high propagation rate constants ( k p ) in water can yield ultra-high molecular weight (UHMW) polymers with predictable molecular weights .…”