Engineering Electrochemical Surface for Efficient Carbon Dioxide Upgrade

Abstract

The increasing atmospheric CO 2 raises many associated issues, such as the rise of global mean temperature, the mass loss of polar ice sheets, and subsequent rise of global average sea level, etc. [3] As a result, there is serious motivation to capture and utilize this kind of greenhouse gas [4] and reduce reliance on fossil fuels by utilizing alternative renewable energies to achieve carbon neutrality. [5] Whilst solar and wind renewable energy sources already play an impressively increasing role in the global energy mix, energy storage systems are required to regulate this intermittent and fluctuating renewable electricity. [6] The residual or excess electrical energy from these intermittent sources can therefore be used to transform CO 2 into valuable fuels and chemicals, acting as one class of long-term energy storage. Based on these driving forces, electrocatalytic CO 2 conversion holds great promise as a future technology to store renewable energy in the long term and sequester CO 2 in the earth's carbon cycle. Generally, electrocatalytic CO 2 conversion and upgrade can take place over a wide range of temperatures and/or pressures. [7] The electrochemical CO 2 reduction reaction (CO 2 RR) at ambient temperature/pressure is considered an ideal route and offers significant opportunities to lower the global carbon footprint with wide applications. [8] CO 2 RR has become a prominent research direction, and it is of paramount importance in the electrochemical and carbon chemical industry. This approach creates a sustainable global-scale carbon-neutral economy, [9] allowing for a more innovative carbon capture and utilization (CCU) instead of carbon capture and storage. [10] CO 2 RR has many economic and environmental benefits, which includes, but is not limited to, its capability to i) reduce carbon emission by efficient utilization and conversion of CO 2 , ii) conveniently convert and store surplus intermittent renewable energies, iii) synthesize useable commercial chemicals for new applications, iv) easily regulate reaction rate/selectivity through applied voltages, and v) adapt to a wide-scale process by applications of modular electrolytic cells. [11] As an emerging part of CCU techniques, CO 2 RR provides a promising opportunity to develop new clean technologies to further tackle the issue of global warming.At its current technological state, the development of CO 2 RR is still in its infancy and faces a series of natural barriers. The Electrochemical CO 2 conversion offers an attractive route for recycling CO 2 with economic and environmental benefits, while the catalytic materials and electrode structures still require further improvements for scale-up application. Electrocatalytic surface and near-surface engineering (ESE) has great potential to advance CO 2 reduction reactions (CO 2 RR) with improved activity, selectivity, energetic efficiency, stability, and reduced overpotentials. This review initially provides a panorama of ESE effects to give a clear perspective and leverage their advantages, i...

Reduced Graphene Oxide Overlayer on Copper Nanocube Electrodes Steers the Selectivity Towards Ethanol in Electrochemical Reduction of Carbon Dioxide

“…The main difference comes with the increased intensity of the (220) plane in the Cu NCbs−rGO‐60 catalyst, which agrees with the predominant catalytic activity toward C 2+ oxygenate products. The presence of dislocation and micro‐strain regions on metal or semiconductor catalysts with dislocation densities has a greater number of undercoordinated sites, which lower the energy barriers for the formation of CO 2 reduction intermediates by suppressing HER to a greater extent [20,21] …”

“…The presence of dislocation and micro-strain regions on metal or semiconductor catalysts with dislocation densities has a greater number of undercoordinated sites, which lower the energy barriers for the formation of CO 2 reduction intermediates by suppressing HER to a greater extent. [20,21] The extent of GO reduction and the defect in GO sheets were estimated from the Raman spectra of the rGO-modified Cu cube samples, Supplementary FigureS1. Both the Cu NCbsÀ rGO-60 and the Cu NCbsÀ rGO-120 show two prominent characteristic peaks at ~1360 cm À 1 and ~1586 cm À 1 , corresponding to the D and G bands, respectively.…”

Vertically Aligned Multiwalled Carbon Nanotube/Cu Catalysts for CO2 Electroreduction

“…This can be achieved through the CO 2 electroreduction reaction (CO 2 ERR) on copper electrodes. Interestingly, Cu is the only known metal element to catalyze this reaction toward hydrocarbon products by itself, which is a result of reaction pathways that are not available for other metals. − Cu holds the tunable ability of binding CO* intermediates with suitable strength for subsequent concerted proton–electron transfer reactions. However, the mechanism of selective production remains elusive and requires further investigation.…”

Insights into Heterogeneous Catalysts under Reaction Conditions by In Situ/Operando Electron Microscopy

“…Electrocatalytic reduction of CO 2 has captured a surge of interest in recent years from the perspective of combating global climate change. [271][272][273][274] The design of active catalysts with controllable surface sites for the activation of CO 2 is key to the reduction, to which recent in situ TEM studies shine some light. In a recent study of Cu nanocrystal catalysts for electrocatalytic conversion of CO 2 to multicarbon products, in situ EC-XANES (electrochemical X-ray absorption near-edge structure) and EC-(S)TEM techniques are used to monitor the morphological changes of the catalysts in CO 2 -saturated 0.1 m KHCO 3 .…”