Efficient hydrogen evolution reaction performance using lignin-assisted chestnut shell carbon-loaded molybdenum disulfide

Abstract

Splitting water to produce hydrogen is considered one of the effective ways to deal with the energy crisis, while high-efficiency hydrogen evolution reaction (HER) requires excellent catalysts. Pt and other precious metal catalysts are not suitable for industrial applications because of their high prices. Molybdenum disulfide based (MoS2) catalysts are considered to be the materials that may replace precious metal catalysts because of their excellent performance. However, MoS2 catalyst still needs to be improved to improve its catalytic performance due to its semiconductor nature and insufficient catalytic active site. In this work, lignin was used as the surface-active material to increase the catalytic active site on MoS2, and chestnut shell carbon (CSC) was used to enhance the electron transport ability of the material. A composite catalyst with excellent HER ability was prepared by a simple hydrothermal method. Lignin promoted the exposure of catalytic active sites on MoS2 through steric and charge effects. In addition, lignin could be depolymerized into phenolic substances through hydrothermal reaction, which not only added a large number of oxygenous functional groups to the MoS2 catalyst, but also improved the electron transport efficiency. Under 5 wt% lignin content, synthesis of composite catalyst (MoS2 @CSC Lig5) has low overpotential (86.84 mV at −10 mA·cm−2 current density), high CdI value (64.59mF·cm−2), and high electron transfer efficiency. All these show that the catalyst has excellent HER ability. In general, we have prepared a catalytic material without adding precious metal materials and with excellent HER ability. It provides help for expanding the application of lignin in the field of electrocatalysis and provides a method for the high-value utilization of chestnut shells.