Dual Metal-Loaded Porous Carbon Materials Derived from Silk Fibroin as Bifunctional Electrocatalysts for Hydrogen Evolution Reaction and Oxygen Evolution Reaction

Abstract

Developing electrocatalysts with high efficiency and long-term stability for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is significant to massively generate hydrogen energy by water splitting. In this work, cobalt and tungsten dual metal-loaded N-doped porous carbon electrocatalysts derived from silk fibroin were successfully prepared through facile carbonization and chemical activation by KCl and applied as efficient electrocatalysts for HER and OER. After chemical activation, the resulting catalysts present a unique hierarchical porous structure with micro-, meso-, and macropores, which is able to expose more implantation sites for catalytic active metals and will in turn promote the efficient diffusion of the electrolyte. The catalyst under the optimized condition (CoW@ACSF) has a specific area of 326.01 m2 g–1. The overpotential at a current density of 10 mA cm –2 of CoW@ACSF is 138.42 ± 10.39 mV toward HER and 492.05 ± 19.04 mV toward OER. Furthermore, the overpotential only increases 101.2 mV toward HER and 66.00 mV toward OER after the long-term stability test of chronopotentiometric test over 10 h, which confirms the excellent stability of the CoW@ACSF, owing to its unique carbon shell structure. This work gives an insight into the design and engineering of silk fibroin-derived carbon materials for electrocatalysis toward HER and OER.

Simultaneous optimization of CoIr alloy nanoparticles and 2D graphitic-N doped carbon support in CoIr@CN by Ir doping for enhanced oxygen and hydrogen evolution reactions

“…The catalyst support has been reported to signicantly improve the dispersion and stability of metal nanoparticles, which act as catalytically active sites. [18][19][20][21][22] Moreover, the chemical bonding between metal nanoparticles and support interface will probably induce the strong metal-support interaction (SMSI) effect to efficiently optimize the electron transfer and local electronic structures of active metal particles, which can further modulate the adsorption energies of reaction intermediates for enhanced catalytic activity. 19,23 Usually, nitrogendoped carbon materials with high surface area, excellent conductivity and easy accessibility can work as a representative support to stabilize metal nanoparticles.…”

Rise of wood-based catalytic electrodes for large-scale hydrogen production

“…3 Over the past few decades, a large number of research efforts have been devoted to synthesise self-supported or porous substrate-supported electrocatalysts as they present remarkable electrochemical performance, especially for largescale hydrogen production at high current density. [4][5][6][7][8] In self-supported electrodes, the substrate materials play a critical role as they transport electrons, electrolytes and gases during the water electrolysis. 9 The mostly used substrates are porous metals (such as metal foam made of iron, nickel, copper, etc.…”

Functional Carbon from Nature: Biomass‐Derived Carbon Materials and the Recent Progress of Their Applications

“…During pyrolysis, silk fibroin decomposes when the temperature exceeds 260 °C, and after 800 °C carbonization, only 32.7% of silk fibroin remains. [261] Cho et al investigated the carbonization process of silk protein and the molecular transformation from fibroin into pseudographitic pyroprotein. [262] Figure 9d shows the TGA curves of worm silk and spider silk.…”