Assembly of Copolymer and Metal-Organic Framework HKUST-1 to Form Cu2-xS/CNFs Intertwining Network for Efficient Electrocatalytic Hydrogen Evolution.

Yuanjuan Bai,Jinbo Hu,Yanran Li,Gonggang Liu

doi:10.3390/nano11061505

Abstract

The construction of complex intertwined networks that provide fast transport pathways for ions/electrons is very important for electrochemical systems such as water splitting, but a challenge. Herein, a three dimensional (3-D) intertwined network of Cu2−xS/CNFs (x = 0 or 0.04) has been synthesized through the morphology-preserved thermal transformation of the intertwined PEG-b-P4VP/ HKUST-1 hybrid networks. The strong interaction between PEG chains and Cu2+ is the key to the successful assembly of PEG-b-P4VP nanofibers and HKUST-1, which inhibits the HKUST-1 to form individual crystalline particles. The obtained Cu2−xS/CNFs composites possess several merits, such as highly exposed active sites, high-speed electronic transmission pathways, open pore structure, etc. Therefore, the 3-D intertwined hierarchical network of Cu2−xS/CNFs displays an excellent electrocatalytic activity for HER, with a low overpotential (η) of 276 mV to reach current densities of 10 mA cm−2, and a smaller Tafel slope of 59 mV dec−1 in alkaline solution.

Highlights

Shahriar Dastjerdi and DanilElectrochemical water splitting is a critical energy conversion process for producing clean and sustainable hydrogen, which is composed of two half-cell reactions: oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) [1,2,3] Electrolysis is a process that consumes electricity, a catalyst is needed to reduce the potential.Pt-based electrocatalysts exhibit the best performance for H2 evolution in strongly acidic electrolytes, their HER activities are substantially diminished under alkaline conditions [4,5] considerable attempts have been devoted to developing sustainable, highly efficient, and non-precious electrocatalysts to meet a target of Pt-based catalysts replacement
[6] Metal-organic frameworks (MOFs) are an intriguing class of porous crystalline materials constructed by the coordination of metal ions or clusters with organic linkers [7,8,9,10,11] For example, HKUST-1({[Cu3 (C9 H3 O6 )2 (H2 O)3 ]}n, aka Cu-BTC) is one of the very first permanently porous MOFs, which has been widely studied for multiple applications [12,13,14] The microporosity and tunable functionality of
The core-crosslinked polymeric linear-like micelles with a PEG shell and a slightly crosslinked P4VP core, designated as PEG-b-P4VP nanofibers (NFs), is synthesized in a water/methanol mixed solvent according to a reported method [28]

Summary

Introduction

Shahriar Dastjerdi and DanilElectrochemical water splitting is a critical energy conversion process for producing clean and sustainable hydrogen, which is composed of two half-cell reactions: oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) [1,2,3] Electrolysis is a process that consumes electricity, a catalyst is needed to reduce the potential.Pt-based electrocatalysts exhibit the best performance for H2 evolution in strongly acidic electrolytes, their HER activities are substantially diminished under alkaline conditions [4,5] considerable attempts have been devoted to developing sustainable, highly efficient, and non-precious electrocatalysts to meet a target of Pt-based catalysts replacement. Afterwards, the Cu2–x S/CNFs composite materials with an intertwined network structure can be prepared with un-changed morphology by using in-situ thermal calcination PEG-b-P4VP@ HKUST-1 precursors. In a PEG-b-P4VP@HKUST-1 composites with core-shell structure.

Results

Conclusion