Ni-N-Doped Carbon-Modified Reduced Graphene Oxide Catalysts for Electrochemical CO2 Reduction Reaction

Fangyuan Wang,Zhiling Song,Zhichao Miao,Jinping Zhao,Yu Liu

doi:10.3390/catal11050561

Abstract

Electrochemical CO2 reduction reaction (CO2RR) is eliciting considerable attention in relation to the carbon cycle and carbon neutrality. As for the practical application of CO2RR, the electrocatalyst is a crucial factor, but, even so, designing and synthesizing an excellent catalyst remains a significant challenge. In this paper, the coordination compound of Ni ions and dimethylglyoxime (DMG) was employed as a precursor to modify reduced graphene oxide (rGO) for CO2RR. The textural properties and chemical bonds of as-obtained rGO, N–C–rGO, Ni–rGO, Ni–N–C, and Ni–N–C–rGO materials were investigated in detail, and the role of Ni, N–C, and rGO in the CO2RR were researched and confirmed. Among all the catalysts, the Ni–N–C–rGO showed the optimal catalytic activity and selectivity with a high current density of 10 mA cm−2 and FE(CO)% of 85% at −0.87 V vs. RHE. In addition, there was no obvious decrease in activity for 10 h. Therefore, the Ni–N–C–rGO is a promising catalyst for CO2RR to CO.

Highlights

In the X-ray diffraction (XRD) patterns (Figure 2a), only a broad peak, which is attributed to the graphitic carbon structure, is detected in the reduced graphene oxide (rGO) and N–C–rGO materials [32,33]
44.5◦, 51.9◦, and 76.4◦, corresponding well with the (111), (200), and (220) crystal planes of metallic Ni (JCPDF card No 04-0850), respectively, indicating that Ni ions are successfully reduced to metallic Ni particles in Ni–rGO, Ni-N-doped carbon (Ni–N–C), and Ni–N–C–rGO materials [34,35]
The large crystalline size of Ni–N–C is ascribed to the absence of rGO, which can improve the dispersion of Ni species

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. There is an urgent need to reduce the amount of CO2 and realize the carbon cycle and carbon neutrality. Different kinds of strategies have been explored to convert CO2 into high value-added products [3,4,5]. Among these strategies, the electrocatalytic CO2 reduction reaction (CO2 RR) to produce valuable products has attracted continuous attention, and can use renewable energies (e.g., wind energy, solar energy, and tidal energy) as a driving force [6,7,8]

Methods

Results

Conclusion