CO2 electroreduction to ethylene via hydroxide-mediated copper catalysis at an abrupt interface
18 May 2018-Science (American Association for the Advancement of Science)-Vol. 360, Iss: 6390, pp 783-787
TL;DR: A copper electrocatalyst at an abrupt reaction interface in an alkaline electrolyte reduces CO2 to ethylene with 70% faradaic efficiency at a potential of −0.55 volts versus a reversible hydrogen electrode (RHE).
Abstract: Carbon dioxide (CO 2 ) electroreduction could provide a useful source of ethylene, but low conversion efficiency, low production rates, and low catalyst stability limit current systems. Here we report that a copper electrocatalyst at an abrupt reaction interface in an alkaline electrolyte reduces CO 2 to ethylene with 70% faradaic efficiency at a potential of −0.55 volts versus a reversible hydrogen electrode (RHE). Hydroxide ions on or near the copper surface lower the CO 2 reduction and carbon monoxide (CO)–CO coupling activation energy barriers; as a result, onset of ethylene evolution at −0.165 volts versus an RHE in 10 molar potassium hydroxide occurs almost simultaneously with CO production. Operational stability was enhanced via the introduction of a polymer-based gas diffusion layer that sandwiches the reaction interface between separate hydrophobic and conductive supports, providing constant ethylene selectivity for an initial 150 operating hours.
Citations
More filters
TL;DR: In this article, the formation of multi-shelled CuO microboxes for the efficient and selective electrocatalytic CO2 reduction to C2H4 was demonstrated, which can effectively convert CO2 into CO2 with a maximum faradaic efficiency of 51.3% in 0.1 M K2SO4.
Abstract: The electroreduction of CO2 to valuable chemicals and fuels offers an effective mean for energy storage. Although CO2 has been efficiently converted into C1 products (e.g., carbon monoxide, formic acid, methane and methanol), its convention into high value-added multicarbon hydrocarbons with high selectivity and activity still remains challenging. Here we demonstrate the formation of multi-shelled CuO microboxes for the efficient and selective electrocatalytic CO2 reduction to C2H4. Such a structure favors the accessibility of catalytically active sites, improves adsorption of reaction intermediate (CO), inhibits the diffusion of produced OH− and promotes C—C coupling reaction. Owing to these unique advantages, the multi-shelled CuO microboxes can effectively convert CO2 into C2H4 with a maximum faradaic efficiency of 51.3% in 0.1 M K2SO4. This work provides an effective way to improve CO2 reduction efficiency via constructing micro- and nanostructures of electrocatalysts.
49 citations
TL;DR: In this article , the authors report reliable ampere-level CO2-to-C2+ electrolysis by heteroatom engineering on Cu catalysts, which achieves a C2+ partial current density of -909 mA cm-2 at -1.15 V versus reversible hydrogen electrode, which outperforms most reported Cu-based catalysts.
Abstract: An ampere-level current density of CO2 electrolysis is critical to realize the industrial production of multicarbon (C2+) fuels. However, under such a large current density, the poor CO intermediate (*CO) coverage on the catalyst surface induces the competitive hydrogen evolution reaction, which hinders CO2 reduction reaction (CO2RR). Herein, we report reliable ampere-level CO2-to-C2+ electrolysis by heteroatom engineering on Cu catalysts. The Cu-based compounds with heteroatom (N, P, S, O) are electrochemically reduced to heteroatom-derived Cu with significant structural reconstruction under CO2RR conditions. It is found that N-engineered Cu (N-Cu) catalyst exhibits the best CO2-to-C2+ productivity with a remarkable Faradaic efficiency of 73.7% under -1100 mA cm-2 and an energy efficiency of 37.2% under -900 mA cm-2. Particularly, it achieves a C2+ partial current density of -909 mA cm-2 at -1.15 V versus reversible hydrogen electrode, which outperforms most reported Cu-based catalysts. In situ spectroscopy indicates that heteroatom engineering adjusts *CO adsorption on Cu surface and alters the local H proton consumption in solution. Density functional theory studies confirm that the high adsorption strength of *CO on N-Cu results from the depressed HER and promoted *CO adsorption on both bridge and atop sites of Cu, which greatly reduces the energy barrier for C-C coupling.
49 citations
TL;DR: In this article, the authors discuss the electrochemical CO2 reduction reaction, relevant figures-of-merit, and configurations for electrolyzers and gas diffusion electrodes, and summarized important developments towards the scaled-up synthesis of commercially valuable carbon monoxide, formic acid, hydrocarbons and alcohols.
Abstract: The synthesis of value-added chemicals from the electrochemical reduction of carbon dioxide is attractive from the perspectives of both sustainable manufacturing and environmental protection. In this review article, we first discussed the electrochemical CO2 reduction reaction, relevant figures-of-merit, and configurations for electrolyzers and gas diffusion electrodes. We then summarized important developments towards the scaled-up synthesis of commercially valuable carbon monoxide, formic acid, hydrocarbons and alcohols. Among all these developments, electrolyzers for generating carbon monoxide and formic acid appear to be approaching close to practical realization in the industry. In contrast, electrolyzers for producing hydrocarbons and alcohols need to be further improved. Finally, directions for future research are suggested.
49 citations
TL;DR: A critical review of classical and improved electrodes, electrocatalysts and reactors is provided in this article, where the principles governing the selection of electrochemical flow reactor or progression of a particular design for laboratory or pilot scale are reviewed integrating the principles of electrochemistry and electrochemical engineering with practical aspects.
Abstract: A critical review of classical and improved electrodes, electrocatalysts and reactors is provided. The principles governing the selection of electrochemical flow reactor or progression of a particular design for laboratory or pilot scale are reviewed integrating the principles of electrochemistry and electrochemical engineering with practical aspects. The required performance, ease of assembly, maintenance schedule and scale-up plans must be incorporated. Reactor designs can be enhanced by decorating their surfaces with nanostructured electrocatalysts. The simple parallel plate geometry design, often in modular, filter-press format, occupies a prominent position, both in the laboratory and in industry and may incorporates porous, 3D or structured electrode surfaces and bipolar electrical connections considering the reaction environment, especially potential- and current-distributions, uniformity of flow, mass transport rates, electrode activity, side reactions and current leakage. Specialised electrode geometries include capillary gap and thin film cells, rotating cylinder electrodes, 3-D porous electrodes, fluidised bed electrodes and bipolar trickle tower reactors. Applications span inorganic, organic electrosynthesis and environmental remediation. Recent developments in cell design: 3D printing, nanostructured, templating 3D porous electrodes, microchannel flow, combinatorial electrocatalyst studies, bioelectrodes and computational modelling. Figures of merit describing electrochemical reactor performance and their use are illustrated. Future research and development needs are suggested.
48 citations
TL;DR: In this paper, the authors identify the critical steps toward C2 products on copper through a combination of energetics from density functional theory and micro-kinetic modeling and propose two simple thermodynamic descriptors that effectively identify C2+ selectivity on metal catalysts beyond copper and hence it defines an intelligible protocol to screen for materials that selectively catalyze CO(2) to C2+) products.
Abstract: Electrochemical reduction of carbon-dioxide/carbon-monoxide (CO(2)R) to fuels and chemicals presents an attractive approach for sustainable chemical synthesis, but it also poses a serious challenge in catalysis. Understanding the key aspects that guide CO(2)R towards value-added multicarbon (C2+) products is imperative in designing an efficient catalyst. Herein, we identify the critical steps toward C2 products on copper through a combination of energetics from density functional theory and micro-kinetic modeling. We elucidate the importance of atomic carbon in directing C2+ selectivity and how it introduces surface structural sensitivity on copper catalysts. This insight enables us to propose two simple thermodynamic descriptors that effectively identify C2+ selectivity on metal catalysts beyond copper and hence it defines an intelligible protocol to screen for materials that selectively catalyze CO(2) to C2+ products.
48 citations
References
More filters
TL;DR: A simple derivation of a simple GGA is presented, in which all parameters (other than those in LSD) are fundamental constants, and only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked.
Abstract: Generalized gradient approximations (GGA’s) for the exchange-correlation energy improve upon the local spin density (LSD) description of atoms, molecules, and solids. We present a simple derivation of a simple GGA, in which all parameters (other than those in LSD) are fundamental constants. Only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked. Improvements over PW91 include an accurate description of the linear response of the uniform electron gas, correct behavior under uniform scaling, and a smoother potential. [S0031-9007(96)01479-2] PACS numbers: 71.15.Mb, 71.45.Gm Kohn-Sham density functional theory [1,2] is widely used for self-consistent-field electronic structure calculations of the ground-state properties of atoms, molecules, and solids. In this theory, only the exchange-correlation energy EXC › EX 1 EC as a functional of the electron spin densities n"srd and n#srd must be approximated. The most popular functionals have a form appropriate for slowly varying densities: the local spin density (LSD) approximation Z d 3 rn e unif
146,533 citations
TL;DR: An efficient scheme for calculating the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set is presented and the application of Pulay's DIIS method to the iterative diagonalization of large matrices will be discussed.
Abstract: We present an efficient scheme for calculating the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set. In the first part the application of Pulay's DIIS method (direct inversion in the iterative subspace) to the iterative diagonalization of large matrices will be discussed. Our approach is stable, reliable, and minimizes the number of order ${\mathit{N}}_{\mathrm{atoms}}^{3}$ operations. In the second part, we will discuss an efficient mixing scheme also based on Pulay's scheme. A special ``metric'' and a special ``preconditioning'' optimized for a plane-wave basis set will be introduced. Scaling of the method will be discussed in detail for non-self-consistent and self-consistent calculations. It will be shown that the number of iterations required to obtain a specific precision is almost independent of the system size. Altogether an order ${\mathit{N}}_{\mathrm{atoms}}^{2}$ scaling is found for systems containing up to 1000 electrons. If we take into account that the number of k points can be decreased linearly with the system size, the overall scaling can approach ${\mathit{N}}_{\mathrm{atoms}}$. We have implemented these algorithms within a powerful package called VASP (Vienna ab initio simulation package). The program and the techniques have been used successfully for a large number of different systems (liquid and amorphous semiconductors, liquid simple and transition metals, metallic and semiconducting surfaces, phonons in simple metals, transition metals, and semiconductors) and turned out to be very reliable. \textcopyright{} 1996 The American Physical Society.
81,985 citations
TL;DR: In this paper, the formal relationship between US Vanderbilt-type pseudopotentials and Blochl's projector augmented wave (PAW) method is derived and the Hamilton operator, the forces, and the stress tensor are derived for this modified PAW functional.
Abstract: The formal relationship between ultrasoft (US) Vanderbilt-type pseudopotentials and Bl\"ochl's projector augmented wave (PAW) method is derived. It is shown that the total energy functional for US pseudopotentials can be obtained by linearization of two terms in a slightly modified PAW total energy functional. The Hamilton operator, the forces, and the stress tensor are derived for this modified PAW functional. A simple way to implement the PAW method in existing plane-wave codes supporting US pseudopotentials is pointed out. In addition, critical tests are presented to compare the accuracy and efficiency of the PAW and the US pseudopotential method with relaxed core all electron methods. These tests include small molecules $({\mathrm{H}}_{2}{,\mathrm{}\mathrm{H}}_{2}{\mathrm{O},\mathrm{}\mathrm{Li}}_{2}{,\mathrm{}\mathrm{N}}_{2}{,\mathrm{}\mathrm{F}}_{2}{,\mathrm{}\mathrm{BF}}_{3}{,\mathrm{}\mathrm{SiF}}_{4})$ and several bulk systems (diamond, Si, V, Li, Ca, ${\mathrm{CaF}}_{2},$ Fe, Co, Ni). Particular attention is paid to the bulk properties and magnetic energies of Fe, Co, and Ni.
57,691 citations
TL;DR: An improved way of estimating the local tangent in the nudged elastic band method for finding minimum energy paths is presented, and examples given where a complementary method, the dimer method, is used to efficiently converge to the saddle point.
Abstract: An improved way of estimating the local tangent in the nudged elastic band method for finding minimum energy paths is presented. In systems where the force along the minimum energy path is large compared to the restoring force perpendicular to the path and when many images of the system are included in the elastic band, kinks can develop and prevent the band from converging to the minimum energy path. We show how the kinks arise and present an improved way of estimating the local tangent which solves the problem. The task of finding an accurate energy and configuration for the saddle point is also discussed and examples given where a complementary method, the dimer method, is used to efficiently converge to the saddle point. Both methods only require the first derivative of the energy and can, therefore, easily be applied in plane wave based density-functional theory calculations. Examples are given from studies of the exchange diffusion mechanism in a Si crystal, Al addimer formation on the Al(100) surfa...
6,825 citations
TL;DR: This paper describes how accurate off-lattice ascent paths can be represented with respect to the grid points, and maintains the efficient linear scaling of an earlier version of the algorithm, and eliminates a tendency for the Bader surfaces to be aligned along the grid directions.
Abstract: A computational method for partitioning a charge density grid into Bader volumes is presented which is efficient, robust, and scales linearly with the number of grid points. The partitioning algorithm follows the steepest ascent paths along the charge density gradient from grid point to grid point until a charge density maximum is reached. In this paper, we describe how accurate off-lattice ascent paths can be represented with respect to the grid points. This improvement maintains the efficient linear scaling of an earlier version of the algorithm, and eliminates a tendency for the Bader surfaces to be aligned along the grid directions. As the algorithm assigns grid points to charge density maxima, subsequent paths are terminated when they reach previously assigned grid points. It is this grid-based approach which gives the algorithm its efficiency, and allows for the analysis of the large grids generated from plane-wave-based density functional theory calculations.
5,417 citations