Development Of Cu-based Catalysts Research Articles

Hydrophobic, Ultrastable Cuδ+ for Robust CO2 Electroreduction to C2 Products at Ampere-Current Levels.

Copper (Cu) is the only known material that can efficiently electrocatalyze CO2 to value-added multicarbon products. Owing to the instability of the Cuδ+ state and microscopic structure in reactions, Cu catalysts are still facing big challenges with low selectivity and poor durability, particularly at high current densities. Herein, we report a rational one-step surface coordination approach for the synthesis of Cu dendrites with an ultrastable Cuδ+ state and hydrophobicity (Cu CF), even after exposure to air for over 6 months. As a result, Cu CF exhibited a C2 FE of 90.6% at a partial current density of 453.3 mA cm-2 in a flow cell. A 400 h stable electrolysis at 800 mA and even a ground-breaking stable operation at a large industrial current of 10 A were achieved in the membrane electrode assembly (MEA) form. We further demonstrated a continuous production of C2H5OH solution with 90% relative purity at 600 mA over 50 h in a solid-electrolyte reactor. Spectroscopy and computation results suggested that Cu(II) carboxylate coordination species formed on the surface of Cu CF, which ensured the stability of the Cuδ+ state and hydrophobicity. As a result, rich active sites and a stable three-phase interface on the catalyst surface were achieved, along with the optimized *CO adsorption strength and adsorption configuration. The mixed *CO adsorption configurations on Cu CF made the *CO dimerization process easier, which promoted the conversion of CO2 to C2 products. This work provides a promising paradigm for the design and development of Cu-based catalysts with ultrahigh stability under industrial current densities.

Tandem electrocatalytic CO2 reduction with Fe-porphyrins and Cu nanocubes enhances ethylene production.

Copper-based tandem schemes have emerged as promising strategies to promote the formation of multi-carbon products in the electrocatalytic CO2 reduction reaction. In such approaches, the CO-generating component of the tandem catalyst increases the local concentration of CO and thereby enhances the intrinsic carbon-carbon (C-C) coupling on copper. However, the optimal characteristics of the CO-generating catalyst for maximizing the C2 production are currently unknown. In this work, we developed tunable tandem catalysts comprising iron porphyrin (Fe-Por), as the CO-generating component, and Cu nanocubes (Cucub) to understand how the turnover frequency for CO (TOFCO) of the molecular catalysts impacts the C-C coupling on the Cu surface. First, we tuned the TOFCO of the Fe-Por by varying the number of orbitals involved in the π-system. Then, we coupled these molecular catalysts with the Cucub and assessed the current densities and faradaic efficiencies. We discovered that all of the designed Fe-Por boost ethylene production. The most efficient Cucub/Fe-Por tandem catalyst was the one including the Fe-Por with the highest TOFCO and exhibited a nearly 22-fold increase in the ethylene selectivity and 100 mV positive shift of the onset potential with respect to the pristine Cucub. These results reveal that coupling the TOFCO tunability of molecular catalysts with copper nanocatalysts opens up new possibilities towards the development of Cu-based catalysts with enhanced selectivity for multi-carbon product generation at low overpotential.

Designing Copper-Based Catalysts for Efficient Carbon Dioxide Electroreduction.

The electroreduction of carbon dioxide (CO2 ) has been emerging as a high- potential approach for CO2 utilization using renewables. When copper (Cu) based catalysts are used, this platform can produce multi-carbon (C2+ ) fuels and chemicals with almost net-zero emission, contributing to the closure of the anthropogenic carbon cycle. Nonetheless, the rational design and development of Cu-based catalysts are critical toward the realization of highly selective and efficient CO2 electroreduction. In this review, first the latest advances in Cu-catalyzed CO2 electroreduction in the product selectivity and electrocatalytic activity are briefly summarized. Then, recent theoretical and mechanistic studies of CO2 electroreduction on Cu-based catalysts are investigated, which serve as programs to design catalysts. Strategies for devising Cu catalysts that aim at promoting different key elementary steps for hydrocarbon and C2+ oxygenates production are further summarized. Moreover, challenges in understanding the mechanism, operando investigation of Cu catalysts and reactions, and systems' influences are also presented. Finally, the future prospects of CO2 electroreduction are discussed.

Advance in Synthesizing Cu-based Catalysts Applying to Dehydrogenation Process: Review

Copper (Cu), a kind of resourceful and low-cost transition metal has attracted a great deal of attention in recent years. Owing to the efficient catalytic activity of Cu nanoparticles (NPs), these particles are perfect candidates as dehydrogenation catalysts, especially in transforming alcohol to carboxylic acid. However, Cu nanoparticles are inclined to agglomerate and inactivating in the catalytic process. As a consequence, it is important to grasp some knowledge of dehydrogenation mechanism and the reason of deactivation, and modification the Cu catalyst properly to improve the catalyst performance. In this study, choosing novel supports and building multimetallic systems are considered good choices. Simultaneously, the synthetic methods of Cu-based catalysts have been discussed concisely. In summary, this review paper has put forward the development and prospects of Cu-based catalysts. We believe that this article will facilitate researchers to accelerate the development of Cu-based catalysts in dehydrogenation process in the future. In addition, dehydrogenation process is particularly important in petroleum processes, this article is also beneficial to the basic research of petrochemical industry.

Efficient Electrochemical Reduction of CO2 to Ethylene

A significant reduction in atmospheric carbon dioxide (CO2) emissions as well as in the development of alternative energy sources will be critical to curb the unwanted effects of climate change (e.g., global warming, erratic weather patterns) and to reduce our dependence on fossil fuels. A number of strategies will need to be pursued simultaneously to indeed reduce anthropogenic CO2 emissions. One such strategy is the use of CO2 as a feedstock for the production of useful chemicals (formic acid, carbon monoxide, hydrocarbons, or alcohols) via electrochemical reduction. This type of electrolysis processes can be driven in a cost effective and sustainable manner if otherwise-wasted renewable energy produced in excess of grid demand is used. Over the past decade, significant advances have been made in the efficient electrocatalytic conversion of CO2 to carbon monoxide (to be used for dense energy carrier production) with scale up and commercialization activities now ongoing. The production of other interesting chemicals such as methanol and ethylene via electroreduction of CO2 has been lagging. This presentation will report on our recent progress to in developing ever more active and especially selective catalysts for the production of ethylene and ethanol. Many researchers are pursuing Cu-based catalysts for this task. While reasonable conversion rates can be achieved (overall current densities exceeding 100 mA/cm2), the main challenge has been achieving selectivity for the desired products of ethylene and ethanol. Typically, other gaseous products such as CO, hydrogen and methane are formed in significant amounts, in addition to ethylene and ethanol. Here we will report our work on the development of Cu-based catalysts that produce 70-80% ethylene and ethanol, at a combined rate exceeding 170 mA/cm2. The presentation will also include an analysis of economic feasibility for the production of ethylene from CO2.