Gold-like activity copper-like selectivity of heteroatomic transition metal carbides for electrocatalytic carbon dioxide reduction reaction

Abstract

An overarching challenge of the electrochemical carbon dioxide reduction reaction (eCO2RR) is finding an earth-abundant, highly active catalyst that selectively produces hydrocarbons at relatively low overpotentials. Here, we report the eCO2RR performance of two-dimensional transition metal carbide class of materials. Our results indicate a maximum methane (CH4) current density of −421.63 mA/cm2 and a CH4 faradic efficiency of 82.7% ± 2% for di-tungsten carbide (W2C) nanoflakes in a hybrid electrolyte of 3 M potassium hydroxide and 2 M choline-chloride. Powered by a triple junction photovoltaic cell, we demonstrate a flow electrolyzer that uses humidified CO2 to produce CH4 in a 700-h process under one sun illumination with a CO2RR energy efficiency of about 62.3% and a solar-to-fuel efficiency of 20.7%. Density functional theory calculations reveal that dissociation of water, chemisorption of CO2 and cleavage of the C-O bond—the most energy consuming elementary steps in other catalysts such as copper—become nearly spontaneous at the W2C surface. This results in instantaneous formation of adsorbed CO—an important reaction intermediate—and an unlimited source of protons near the tungsten surface sites that are the main reasons for the observed superior activity, selectivity, and small potential.

Data-Driven Investigation of Tellurium-Containing Semiconductors for CO2 Reduction: Trends in Adsorption and Scaling Relations

“… 6 Recently, materials discovery has led to new compositions that have shown dramatic improvements in efficiency and activity, such as W 2 C for the photocatalytic and Cu–Al for the electrocatalytic CO 2 RR, supporting the need for further materials discovery approaches. 7 , 8 …”

Electrochemical Activated Nitrogen‐doped Carbon as Highly Efficient Electrocatalysts for Hydrogen Evolution Reactions

“…Figure S6 presented Nyquist diagrams of catalysts with an equivalent circuit used to fit impedance data. According to the fitting results, the charge transfer resistance (R ct ) of activated catalyst was obviously smaller than that before activation [59] …”

“…According to the fitting results, the charge transfer resistance (R ct ) of activated catalyst was obviously smaller than that before activation. [59] Moreover, the graphite rod was also used as the counter electrode to exclude the Pt contamination as presented in Figure S7 and Figure S8. The electrochemical activation in catalysts displayed similar trend with that activated using Pt counter electrode.…”

Anode Catalysts in CO2 Electrolysis: Challenges and Untapped Opportunities

“…In terms of the reduction products, CO and HCOO – were the main products during the longest experiments, both formed via the transfer of two electrons ( Figure 5 C). There is one outlier entry, reporting a stable CH 4 production (i.e., eight-electron process) in a zero-gap cell for 700 h. 85 The highest current densities were reported for systems where C2+ formation was the main CO2R pathway. High current densities, however, go hand in hand with short measurement times, highlighting that the partial crossover of the liquid products formed to the anode side can influence the operation of the electrolyzer.…”