Porous Carbon Nanofibers Derived from Silk Fibroin through Electrospinning as N-Doped Metal-Free Catalysts for Hydrogen Evolution Reaction in Acidic and Alkaline Solutions

Abstract

Water electrolysis is considered as one promising strategy for hydrogen production, and thus, preparing electrocatalysts of superior efficiency and low cost for a hydrogen evolution reaction (HER) in a wide pH range is of paramount importance. In this research, N-doped porous carbon nanofibers derived from silk fibroin by KCl chemical activation are successfully synthesized as the metal-free catalyst for the HER under both acidic and alkaline conditions. After chemical activation of KCl, hierarchical porous structures are formed. Besides, it is found that the concentration of KCl in the electrospun membrane will affect the maintenance of the fibrous morphology for the carbonized samples due to the destruction of β-sheets in silk fibroin induced by KCl. The specific surface area of the optimized sample, 4%-SPCNF, increased by nearly nine times compared with that without activation because of the hierarchical pores and large through pores between fibers. Meanwhile, the porosity increases from 59.87 to 80.28% due to the existence of through pores. Moreover, the 4%-SPCNF has remarkable stability and durability since the carbon substrate is resistant against the corrosion of the electrolyte. Our work provides insights into the design and engineering of silk fibroin-derived carbon nanofibers for metal-free catalysts of the HER under acidic and alkaline conditions.

Immobilization of molecular complexes on graphitized carbon cloth as stable and hybrid electrocatalysts for enhanced hydrogen evolution reaction and oxygen evolution reaction

“…9c). The Tafel slope values are the lowest compared to many nanocomposites 1 and other transition metal nanosheets. 35 The metal complex on the modified glassy carbon surface undergoes oxidation from Ni(0) to Ni( ii ), leading to reduction of the hydroxide ion to an oxygen molecule.…”

“…context, Hydrogen has tremendous potential as a promising future energy currency and is prognosticated as a very prominent next-generation renewable energy source 1 . Hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) have been recognised as clean and sustainable ways of generating green energy 2 .…”

“…In this context, hydrogen has tremendous potential as a promising future energy currency and is prognosticated as a very prominent next-generation renewable energy source. 1 The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) have been recognised as clean and sustainable ways of generating green energy. 2 Researchers have devoted significant and sustained effort to develop inexpensive, durable, and efficient electrocatalysts for water splitting reactions.…”

Collagen and Silk Fibroin as Promising Candidates for Constructing Catalysts

“…Therefore, the bottom-up method for producing silk fibroin-derived carbon-based catalysts is also widely used. Hongzhe He [ 152 ] first dissolved degummed silk in a CaCl 2 /CH 3 CH 2 OH/H 2 O ternary solvent system and then self-assembled to form RSF. The electrospinning solution of silk fibroin nanofibers was prepared by dissolving RSF fibroin in anhydrous formic acid.…”

Ultrathin NiPt Single-Atom Alloy for Synergistically Accelerating Alkaline Hydrogen Evolution

“…Hydrogen (H 2 ), as environment-friendly energy with a high gravimetric energy density, is expected to advance the deep decarbonization of the energy market by taking the place of traditional fossil fuels. − Alkaline hydrogen evolution reaction (HER) powered by intermittent renewable electricity has emerged as a prospective method in recent years because of its preferable advantages like general stability, high product purity, and satisfactory industrial value. − To date, platinum (Pt)-based catalysts have been recognized as benchmark HER catalysts due to their optimum binding ability with hydrogen. − Some other platinum group metals like Ru, Rh, and Ir also show high performance for HER. − However, their high cost and scarcity restrict their large-scale commercial production. Single-atom catalysts have become an effective approach.…”