scispace - formally typeset
Search or ask a question
Journal ArticleDOI

CO2 electroreduction to ethylene via hydroxide-mediated copper catalysis at an abrupt interface

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
Journal ArticleDOI
TL;DR: A fundamental understanding of the interaction between CO2 and Ni surfaces at atomic level is necessary in this paper, where a Ni-based catalysts play an important role in the chemical transformation of CO2.
Abstract: Nickel-based catalysts play an important role in the chemical transformation of CO2. A fundamental understanding of the interaction between CO2 and Ni surfaces at atomic level is necessary. In this...

32 citations

Journal ArticleDOI
TL;DR: In this paper, a self-formed tandem catalyst designed for a cascade electroreduction of CO2 to C2H4 was constructed using oxygen partial pressure-controlled calcination.
Abstract: Electrocatalysts for CO2 electroreduction require not only high-performance active materials to control the series reaction but also conductive and durable supports to ensure long-term stability under harsh operating conditions. Instead of conventional heterogeneous catalysts made by attaching metal on supports, we manufactured a self-formed tandem catalyst designed for a cascade electroreduction of CO2 to C2H4. Using oxygen partial pressure-controlled calcination, electrospun copper acetate/polyacrylonitrile nanofibers were successfully transformed into porous carbon nanofibers consisting of doped N and metallic Cu particles. Doped nitrogen atoms adjacent to Cu atoms trigger the reaction by increasing the amount of CO* on the Cu surfaces, which lowers the energy required for CO dimerization that is used for C2H4 production. The Cu-embedded N-doped carbon nanofibers exhibit a C2H4 faradaic efficiency of 62% at a potential of −0.57 V vs. RHE with high current density of 600 mA cm−2 and excellent long-term stability. DFT calculations suggest that the lowered overpotential originates from the decreased CO dimerization energy barrier due to the doped N triggering CO production around the Cu particles.

31 citations

Journal ArticleDOI
TL;DR: In this article, the authors reported an electrocatalytic route to produce ethylamine selectively through an electroreduction of acetonitrile at ambient temperature and pressure. But, the synthesis is often hindered by the poor selectivity because of the formation of secondary and tertiary amine byproducts.
Abstract: Electrifying chemical manufacturing using renewable energy is an attractive approach to reduce the dependence on fossil energy sources in chemical industries Primary amines are important organic building blocks; however, the synthesis is often hindered by the poor selectivity because of the formation of secondary and tertiary amine byproducts Herein, we report an electrocatalytic route to produce ethylamine selectively through an electroreduction of acetonitrile at ambient temperature and pressure Among all the electrocatalysts, Cu nanoparticles exhibit the highest ethylamine Faradaic efficiency (~96%) at −029 V versus reversible hydrogen electrode Under optimal conditions, we achieve an ethylamine partial current density of 846 mA cm−2 A 20-hour stable performance is demonstrated on Cu at 100 mA cm−2 with an 86% ethylamine Faradaic efficiency Moreover, the reaction mechanism is investigated by computational study, which suggests the high ethylamine selectivity on Cu is due to the moderate binding affinity for the reaction intermediates Industrial synthesis of primary amine often features poor selectivity because of the formation of secondary and tertiary amine byproducts Here, the authors report an electrocatalytic route to ethylamine through selective electroreduction of acetonitrile at ambient temperature and pressure

31 citations

Journal ArticleDOI
TL;DR: In this article , the structure evolution of a superparticle with an assembly structure was investigated for CO2 reduction and the results showed that the structure of the superparticles can be improved by controlling structural reconstruction.
Abstract: Structural reconstruction is a process commonly observed for Cu‐based catalysts in electrochemical CO2 reduction. The Cu‐based precatalysts with structural complexity often undergo sophisticated structural reconstruction processes, which may offer opportunities for enhancing the electrosynthesis of multicarbon products (C2+ products) but remain largely uncertain due to various new structural features possibly arising during the processes. In this work, the Cu2O superparticles with an assembly structure are demonstrated to undergo complicated structure evolution under electrochemical reduction condition, enabling highly selective CO2‐to‐C2+ products conversion in electrocatalysis. As revealed by electron microscopic characterization together with in situ X‐ray absorption spectroscopy and Raman spectroscopy, the building blocks inside the superparticle fuse to generate numerous grain boundaries while those in the outer shell detach to form nanogap structures that can efficiently confine OH− to induce high local pH. Such a combination of unique structural features with local reaction environment offers two important factors for facilitating C−C coupling. Consequently, the Cu2O superparticle‐derived catalyst achieves high faradaic efficiencies of 53.2% for C2H4 and 74.2% for C2+ products, surpassing the performance of geometrically simpler Cu2O cube‐derived catalyst and most reported Cu electrocatalysts under comparable conditions. This work provides insights for rationally designing highly selective CO2 reduction electrocatalysts by controlling structural reconstruction.

31 citations

References
More filters
Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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