Graphene Supported Tungsten Carbide as Catalyst for Electrochemical Reduction of CO2

Abstract

<div>Electrochemical reduction of CO2 to useful chemical and fuels in an energy efficient way is currently an expensive and inefficient process. Recently, low-cost transition metal-carbides (TMCs) are proven to exhibit similar electronic structure similarities to Platinum-Group-Metal (PGM) catalysts and hence can be good substitutes for some important reduction reactions. In this work, we test graphenesupported WC (Tungsten Carbide) nanocluster as an electrocatalyst for the CO2 reduction reaction. Specifically, we perform DFT studies to understand various possible reaction mechanisms and determine the lowest thermodynamic energy landscape of CO2 reduction to various products such as CO, HCOOH, CH3OH, and CH4. This in-depth study of reaction energetics could lead to improvements and develop more efficient electrocatalysts for CO2 reduction.<br></div>

Electrochemical Reduction of Carbon Dioxide on Graphene-Based Catalysts

“…In addition to copper-based catalysts, WC [ 13 ], Bi [ 17 ], In 2 O 3 [ 37 ], and Pd-In [ 40 ] materials were supported on GMs, and a good catalytic performance toward the ECO 2 RR has been accomplished. For instance, three-dimensional Pd/graphene (Pd/3D-rGO), In/3D-rGO, and Pd-In/3D-rGO catalysts were prepared by a mild method that combined chemical and hydrothermal steps [ 40 ].…”

“…Due to this, the selectivity for the desired products is not usually very high, and it is also conditioned by the hydrogen evolution reaction (HER; E 0 = 0.000 V), which competes with the reaction under study. This currently raises the following challenges for the ECO 2 RR: the need for an increased reaction efficiency, the need for a decreased overpotential to overcome energy barriers and suppress the HER, and the need to obtain moderately high current densities for commercial applications [ 13 , 14 ]. …”

“…For these reasons, current research is focused on the development of electrocatalysts that are chemically stable and inexpensive, have an appropriate shelf life, have an adequate product selectivity to promote their formation, and (ultimately) have the ability to operate at industry-acceptable current densities [ 13 , 15 ]. Various catalysts have been developed to improve the energy efficiency of the electrochemical reduction of CO 2 with metals from the d-block (Cu, Co Pt, Fe, Au, Pd, Ag, Zn, Ni, etc.)…”

“…It should be noted that a strong CO* bonding poisons the catalyst, and the HER is preferred. On the other hand, weak CO* adsorption can result in CO desorption, and the reduction will therefore not continue towards other C 1 products [ 13 ].…”