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1.
The electrochemical carbon dioxide reduction reaction (E-CO2RR) to formate is a promising strategy for mitigating greenhouse gas emissions and addressing the global energy crisis. Developing low-cost and environmentally friendly electrocatalysts with high selectivity and industrial current densities for formate production is an ideal but challenging goal in the field of electrocatalysis. Herein, novel titanium-doped bismuth nanosheets (Ti Bi NSs) with enhanced E-CO2RR performance are synthesized through one-step electrochemical reduction of bismuth titanate (Bi4Ti3O12). We comprehensively evaluated Ti Bi NSs using in situ Raman spectra, finite element method, and density functional theory. The results indicate that the ultrathin nanosheet structure of Ti Bi NSs can accelerate mass transfer, while the electron-rich properties can accelerate the production of *CO2 and enhance the adsorption strength of *OCHO intermediate. The Ti Bi NSs deliver a high formate Faradaic efficiency (FEformate) of 96.3% and a formate production rate of 4032 µmol h−1 cm−2 at −1.01 V versus RHE. An ultra-high current density of −338.3 mA cm−2 is achieved at −1.25 versus RHE, and simultaneously FEformate still reaches more than 90%. Furthermore, the rechargeable Zn–CO2 battery using Ti Bi NSs as a cathode catalyst achieves a maximum power density of 1.05 mW cm−2 and excellent charging/discharging stability of 27 h.  相似文献   

2.
The electrocatalytic transformation of carbon dioxide (CO2) to formate is a promising route for highly efficient conversion and utilization of CO2 gas, due to the low production cost and the ease of storage of formate. In this work, porous poly(ionic liquid) (PPIL)-based tin-silver (Sn-Ag) bimetallic hybrids (PPILm-SnxAg10-x) are prepared for high-performance formate electrolytic generation. Under optimal conditions, an excellent formate Faradaic efficiency of 95.5% with a high partial current density of 214.9 mA cm−2 is obtained at −1.03 V (vs reversible hydrogen electrode). Meanwhile, the high selectivity of formate (>≈83%) is maintained in a wide potential range (>630 mV). Mechanistic studies demonstrate that the presence of Ag-species is vital for the formation, maintenance, and high dispersion of tetravalent Sn(IV)-species, which accounts for the active sites for CO2-to-formate conversion. Further, the introduction of Ag-species significantly enhances the activity by increasing the electron density near the Fermi energy level.  相似文献   

3.
Engineering novel Sn-based bimetallic materials could provide intriguing catalytic properties to boost the electrochemical CO2 reduction. Herein, the first synthesis of homogeneous Sn1−xBix alloy nanoparticles (x up to 0.20) with native Bi-doped amorphous SnOx shells for efficient CO2 reduction is reported. The Bi-SnOx nanoshells boost the production of formate with high Faradaic efficiencies (>90%) over a wide potential window (−0.67 to −0.92 V vs RHE) with low overpotentials, outperforming current tin oxide catalysts. The state-of-the-art Bi-SnOx nanoshells derived from Sn0.80Bi0.20 alloy nanoparticles exhibit a great partial current density of 74.6 mA cm−2 and high Faradaic efficiency of 95.8%. The detailed electrocatalytic analyses and corresponding density functional theory calculations simultaneously reveal that the incorporation of Bi atoms into Sn species facilitates formate production by suppressing the formation of H2 and CO.  相似文献   

4.
Electrochemical CO2 reduction reaction (CO2RR) to value-added chemicals/fuels is an effective strategy to achieve the carbon neutral. Palladium is the only metal to selectively produce formate via CO2RR at near-zero potentials. To reduce cost and improve activity, the high-dispersive Pd nanoparticles on hierarchical N-doped carbon nanocages (Pd/hNCNCs) are constructed by regulating pH in microwave-assisted ethylene glycol reduction. The optimal catalyst exhibits high formate Faradaic efficiency of >95% within −0.05–0.30 V and delivers an ultrahigh formate partial current density of 10.3 mA cm−2 at the low potential of −0.25 V. The high performance of Pd/hNCNCs is attributed to the small size of uniform Pd nanoparticles, the optimized intermediates adsorption/desorption on modified Pd by N-doped support, and the promoted mass/charge transfer kinetics arising from the hierarchical structure of hNCNCs. This study sheds light on the rational design of high-efficient electrocatalysts for advanced energy conversion.  相似文献   

5.
Optimizing the coordination structure and microscopic reaction environment of isolated metal sites is promising for boosting catalytic activity for electrocatalytic CO2 reduction reaction (CO2RR) but is still challenging to achieve. Herein, a newly electrostatic induced self-assembly strategy for encapsulating isolated Ni-C3N1 moiety into hollow nano-reactor as I-Ni SA/NHCRs is developed, which achieves FECO of 94.91% at −0.80 V, the CO partial current density of ≈−15.35 mA cm−2, superior to that with outer Ni-C2N2 moiety (94.47%, ≈−12.06 mA cm−2), or without hollow structure (92.30%, ≈−5.39 mA cm−2), and high FECO of ≈98.41% at 100 mA cm−2 in flow cell. COMSOL multiphysics finite-element method and density functional theory (DFT) calculation illustrate that the excellent activity for I-Ni SA/NHCRs should be attributed to the structure-enhanced kinetics process caused by its hollow nano-reactor structure and unique Ni-C3N1 moiety, which can enrich electron on Ni sites and positively shift d-band center to the Fermi level to accelerate the adsorption and activation of CO2 molecule and *COOH formation. Meanwhile, this strategy also successfully steers the design of encapsulating isolated iron and cobalt sites into nano-reactor, while I-Ni SA/NHCRs-based zinc-CO2 battery assembled with a peak power density of 2.54 mW cm−−2 is achieved.  相似文献   

6.
Electrochemical CO2 reduction reaction (CO2RR), powered by renewable electricity, has attracted great attention for producing high value-added fuels and chemicals, as well as feasibly mitigating CO2 emission problem. Here, this work reports a facile hard template strategy to prepare the Ni@N-C catalyst with core–shell structure, where nickel nanoparticles (Ni NPs) are encapsulated by thin nitrogen-doped carbon shells (N-C shells). The Ni@N-C catalyst has demonstrated a promising industrial current density of 236.7 mA cm−2 with the superb FECO of 97% at −1.1 V versus RHE. Moreover, Ni@N-C can drive the reversible Zn-CO2 battery with the largest power density of 1.64 mW cm−2, and endure a tough cycling durability. These excellent performances are ascribed to the synergistic effect of Ni@N-C that Ni NPs can regulate the electronic microenvironment of N-doped carbon shells, which favor to enhance the CO2 adsorption capacity and the electron transfer capacity. Density functional theory calculations prove that the binding configuration of N-C located on the top of Ni slabs (Top-Ni@N-C) is the most thermodynamically stable and possess a lowest thermodynamic barrier for the formation of COOH* and the desorption of CO. This work may pioneer a new method on seeking high-efficiency and worthwhile electrocatalysts for CO2RR and Zn-CO2 battery.  相似文献   

7.
Ni single-atom catalysts (SACs) are appealing for electrochemical reduction CO2 reduction (CO2RR). However, regulating the balance between the activity and conductivity remains a challenge to Ni SACs due to the limitation of substrates structure. Herein, the intrinsic performance enhancement of Ni SACs anchored on quasi-one-dimensional graphene nanoribbons (GNRs) synthesized is demonstrated by longitudinal unzipping carbon nanotubes (CNTs). The abundant functional groups on GNRs can absorb Ni atoms to form rich Ni–N4–C sites during the anchoring process, providing a high intrinsic activity. In addition, the GNRs, which maintain a quasi-one-dimensional structure and possess a high conductivity, interconnect with each other and form a conductive porous framework. The catalyst yields a 44 mA cm−2 CO partial current density and 96% faradaic efficiency of CO (FECO) at −1.1 V vs RHE in an H-cell. By adopting a membrane electrode assembly (MEA) flow cell, a 95% FECO and 2.4 V cell voltage are achieved at 200 mA cm−2 current density. This work provides a rational way to synthesize Ni SACs with a high Ni atom loading, porous morphology, and high conductivity with potential industrial applications.  相似文献   

8.
Electroreduction of CO2 to CO is a promising route for greenhouse gas resource utilization, but it still suffers from impractical current density and poor durability. Here, a nanosheet shell (NS) vertically standing on the Ag hollow fiber (NS@Ag HF) surface formed by electrochemical surface reconstruction is reported. As-prepared NS@Ag HF as a gas penetration electrode exhibited a high CO faradaic efficiency of 97% at an ultra-high current density of 2.0 A cm−2 with a sustained performance for continuous >200 h operation. The experimental and theoretical studies reveal that promoted surface electronic structures of NS@Ag HF by the nanosheets not only suppress the competitive hydrogen evolution reaction but also facilitate the CO2 reduction kinetics. This work provides a feasible strategy for fabricating robust catalysts for highly efficient and stable CO2 reduction.  相似文献   

9.
Single-atom nickel catalysts hold great promise in the application of electrocatalytic carbon dioxide reduction reaction (CO2RR), but suffer from the sluggish kinetics and serious competitive hydrogen evolution reaction (HER), which restrict their overall catalytic performance. Herein, we report a boron-bridging strategy to manipulate the atomic coordination structure and construct a single-atom nickel catalyst with an active center of NiN4B2 to realize excellent CO2RR performance. Density functional theory analysis suggests that the unique NiN4B2 sites with tuned electronic structure facilitate the adsorption of CO2 molecules and effectively suppress the HER pathway by increasing corresponding energy barrier. As-obtained Ni-SAs@BNC catalyst with a NiN4B2 structure exhibits significantly enhanced catalytic activity and selectivity than commonly used single-atom nickel catalysts with a NiN4 structure, especially at high applied potentials. A high current density of up to (214 ± 21) mA cm−2 at a potential of −1.2 V with a high CO Faraday efficiency (FECO) of ∼97% was achieved in a flow cell. This work inspires new insights into the rational design of atomic coordination structure of single-atom catalysts with tunable electronic structure for superior electrocatalytic activities.  相似文献   

10.
Metal-organic frameworks (MOFs) as a promising platform for electrocatalytic CO2 conversion are still restricted by the low efficiency or unsatisfied selectivity for desired products. Herein, zirconium-based porphyrinic MOF hollow nanotubes with Cd sites (Cd-PCN-222HTs) are reported for electrocatalytic CO2-to-CO conversion. The dispersed Cd species are anchored in PCN-222HTs and coordinated by N atoms of porphyrin structures. It is discovered that Cd-PCN-222HTs have glorious electrocatalytic activity for selective CO production in ionic liquid-water (H2O)-acetonitrile (MeCN) electrolyte. The CO Faradaic efficiency (FECO) of >80% could be maintained in a wide potential range from −2.0 to −2.4 V versus Ag/Ag+, and the maximum current density could reach 68.0 mA cm−2 at −2.4 V versus Ag/Ag+ with a satisfied turnover frequency of 26 220 h−1. The enhanced efficiency of electrocatalytic CO2 conversion of Cd-PCN-222HTs is closely related to its hollow structure, anchored Cd species, and good synergistic effect with electrolyte. The density functional theory calculations indicate that the dispersed Cd sites anchored in PCN-222HTs not only favor the formation of *COOH intermediate but also hinder the hydrogen evolution reaction, resulting in high activity of electrocatalytic CO2-to-CO conversion.  相似文献   

11.
Post-combustion flue gas (mainly containing 5–40% CO2 balanced by N2) accounts for about 60% global CO2 emission. Rational conversion of flue gas into value-added chemicals is still a formidable challenge. Herein, this work reports a β-Bi2O3-derived bismuth (OD-Bi) catalyst with surface coordinated oxygen for efficient electroreduction of pure CO2, N2, and flue gas. During pure CO2 electroreduction, the maximum Faradaic efficiency (FE) of formate reaches 98.0% and stays above 90% in a broad potential of 600 mV with a long-term stability of 50 h. Additionally, OD-Bi achieves an ammonia (NH3) FE of 18.53% and yield rate of 11.5 µg h−1 mgcat−1 in pure N2 atmosphere. Noticeably, in simulated flue gas (15% CO2 balanced by N2 with trace impurities), a maximum formate FE of 97.3% is delivered within a flow cell, meanwhile above 90% formate FEs are obtained in a wide potential range of 700 mV. In-situ Raman combined with theory calculations reveals that the surface coordinated oxygen species in OD-Bi can drastically activate CO2 and N2 molecules by selectively favors the adsorption of *OCHO and *NNH intermediates, respectively. This work provides a surface oxygen modulation strategy to develop efficient bismuth-based electrocatalysts for directly reducing commercially relevant flue gas into valuable chemicals.  相似文献   

12.
Recent studies have found that the existence of oxygen around the active sites may be essential for efficient electrochemical CO2-to-CO conversion. Hence, this work proposes the modulation of oxygen coordination and investigates the as-induced catalytic behavior in CO2RR. It designs and synthesizes conjugated phthalocyanine frameworks catalysts (CPF-Co) with abundant CoN4 centers as an active source, and subsequently modifies the electronic structure of CPF-Co by introducing graphene oxide (GO) with oxygen-rich functional groups. A systematic study reveals that the axial coordination between oxygen and the catalytic sites could form an optimized O-CoN4 structure to break the electron distribution symmetry of Co, thus reducing the energy barrier to the activation of CO2 to COOH*. Meanwhile, by adjusting the content of oxygen, the proper supports can also facilitate the charge transfer efficiency between the matrix layer and the catalytic sites. The optimized CPF-Co@LGO exhibits a high TOF value (2.81 s−1), CO selectivity (97.6%) as well as stability (24 h) at 21 mA cm−2 current density. This work reveals the modulation of oxygen during CO2RR and provides a novel strategy for the design of efficient electrocatalysts, which may inspire new exploration and principles for CO2RR.  相似文献   

13.
Electrochemical CO2 reduction reaction (CO2RR) is a promising approach to convert CO2 to carbon-neutral fuels using external electric powers. Here, the Bi2S3-Bi2O3 nanosheets possessing substantial interface being exposed between the connection of Bi2S3 and Bi2O3 are prepared and subsequently demonstrate to improve CO2RR performance. The electrocatalyst shows formate Faradaic efficiency (FE) of over 90% in a wide potential window. A high partial current density of about 200 mA cm?2 at ?1.1 V and an ultralow onset potential with formate FE of 90% are achieved in a flow cell. The excellent electrocatalytic activity is attributed to the fast-interfacial charge transfer induced by the electronic interaction at the interface, the increased number of active sites, and the improved CO2 adsorption ability. These collectively contribute to the faster reaction kinetics and improved selectivity and consequently, guarantee the superb CO2RR performance. This study provides an appealing strategy for the rational design of electrocatalysts to enhance catalytic performance by improving the charge transfer ability through constructing a functional heterostructure, which enables interface engineering toward more efficient CO2RR.  相似文献   

14.
Electrocatalytic CO2 reduction reaction (CO2RR) toward formate production can be operated under mild conditions with high energy conversion efficiency while migrating the greenhouse effect. Herein, an integrated 3D open network of interconnected bismuthene arrays (3D Bi-ene-A/CM) is fabricated via in situ electrochemically topotactic transformation from BiOCOOH nanosheet arrays supported on the copper mesh. The resulted 3D Bi-ene-A/CM consists of 2D atomically thin metallic bismuthene (Bi-ene) in the form of an integrated array superstructure with a 3D interconnected and open network, which harvests the multiple structural advantages of both metallenes and self-supported electrodes for electrocatalysis. Such distinctive superstructure affords the maximized quantity and availability of the active sites with high intrinsic activity and superior charge and mass transfer capability, endowing the catalyst with good CO2RR performance for stable formate production with high Faradaic efficiency (≈90%) and current density (>300 mA cm?2). Theoretical calculation verifies the superior intermediate stabilization of the dominant Bi plane during CO2RR. Moreover, by further coupling anodic methanol oxidation reaction, an exotic electrolytic system enables highly energy-efficient and value-added pair-electrosynthesis for concurrent formate production at both electrodes, achieving substantially improved electrochemical and economic efficiency and revealing the feasibility for practical implementation.  相似文献   

15.
The rolling-off phenomenon of device efficiency at high current density caused by quenching of luminescence in perovskite light-emitting diodes (PeLED) is challenging to be solved. Here, 2-amino-5-iodopyrazine (AIPZ) is dissolved in a mixed solvent of chlorobenzene (CB)/isopropanol (IPA) (7:3 volume ratio) for surface post-treatment of FAPbI3 perovskite film. The interaction of AIPZ and perovskite surface not only balances the charge injection but also passivates defects to enhance radiative recombination in PeLED. Therefore, the PeLED champion yields peak external quantum efficiency reaching 23.2% at the current density of 45 mA cm−2 with a radiance brightness of 290 W sr−1 m−2. More importantly, the rolling-off of device efficiency is significantly reduced. The lowest rolling-off devices can maintain 80% of peak EQE (22.1%) at a high current density of 460 mA cm−2, whereas the control device only retains 25% of the peak EQE value. This work provides an effective strategy to improve performance and reduce the EQE rolling-off of PeLED for practical application.  相似文献   

16.
Tuning the coordination environment and geometric structures of single atom catalysts is an effective approach for regulating the reaction mechanism and maximize the catalytic efficiency of single-atom centers. Here, a template-based synthesis strategy is proposed for the synthesis of high-density NiNx sites anchored on the surface of hierarchically porous nitrogen-doped carbon nanofibers (Ni-HPNCFs) with different coordination environments. First-principles calculations and advanced characterization techniques demonstrate that the single Ni atom is strongly coordinated with both pyrrolic and pyridinic N dopants, and that the predominant sites are stabilized by NiN3 sites. This dual engineering strategy increases the number of active sites and utilization efficiency of each single atom as well as boosts the intrinsic activity of each active site on a single-atom scale. Notably, the Ni-HPNCF catalyst achieves a high CO Faradaic efficiency (FECO) of 97% at a potential of −0.7 V, a high CO partial current density (jCO) of 49.6 mA cm−2 (−1.0 V), and a remarkable turnover frequency of 24 900 h−1 (−1.0 V) for CO2 reduction reactions (CO2RR). Density functional theory calculations show that compared to pyridinic-type NiNx, the pyrrolic-type NiN3 moieties display a superior CO2RR activity over hydrogen evolution reactions, resulting in their superior catalytic activity and selectivity.  相似文献   

17.
Low-cost solution-processed CuIn(S,Se)2 (CISSe) has great potential for large-scale production of photovoltaics (PV). However, low power conversion efficiency caused by poor crystallinity is one of the main drawbacks compared to vacuum-processed CISSe solar cells. In this work, three strategies for sodium (Na) incorporation into solution-processed CISSe by soaking in sodium chloride (NaCl) aqueous-ethanol solution [1 molarity (M) for 10 minutes (min)], either prior to absorber deposition (pre-deposition treatment, Pre-DT), before selenization (pre-selenization treatment, Pre-ST), or after selenization (post-selenization treatment, PST) are researched. The Pre-ST CISSe solar cells achieve a better PV performance than those from the other two strategies of Na incorporation. For optimization, soaking times (5, 10, and 15 min) and NaCl concentrations (from 0.2 to 1.2 m ) of the Pre-ST are researched. The highest efficiency achieved is 9.6% with an open-circuit voltage (Voc) of 464.5 mV, a short-circuit current density (jsc) of 33.4 mA cm−2, and a fill factor (FF) of 62.0%. Compared to the reference CISSe solar cell, Voc, jsc, FF, and efficiency of the champion Pre-ST CISSe device are improved absolutely by 61.0 mV, 6.5 mA cm−2, 9%, and 3.8%, respectively. Simultaneously, the open-circuit voltage deficit, the back contact barrier, and the bulk recombination are found to be reduced for Pre-ST CISSe.  相似文献   

18.
Electrochemical CO2 reduction reaction (CO2RR) is a promising strategy for waste CO2 utilization and intermittent electricity storage. Herein, it is reported that bimetallic Cu/Pd catalysts with enhanced *CO affinity show a promoted CO2RR performance for multi-carbon (C2+) production under industry-relevant high current density. Especially, bimetallic Cu/Pd-1% catalyst shows an outstanding CO2-to-C2+ conversion with 66.2% in Faradaic efficiency (FE) and 463.2 mA cm−2 in partial current density. An increment in the FE ratios of C2+ products to CO  for Cu/Pd-1% catalyst further illuminates a preferable C2+ production. In situ Raman spectra reveal that the atop-bounded CO is dominated by low-frequency band CO on Cu/Pd-1% that leads to C2+ products on bimetallic catalysts, in contrast to the majority of high-frequency band CO on Cu that favors the formation of CO. Density function theory calculation confirms that bimetallic Cu/Pd catalyst enhances the *CO adsorption and reduces the Gibbs free energy of the C C coupling process, thereby favoring the formation of C2+ products.  相似文献   

19.
Semiconductor colloidal quantum wells (CQWs) provide anisotropic emission behavior originating from their anisotropic optical transition dipole moments (TDMs). Here, solution-processed colloidal quantum well light-emitting diodes (CQW-LEDs) of a single all-face-down oriented self-assembled monolayer (SAM) film of CQWs that collectively enable a supreme level of IP TDMs at 92% in the ensemble emission are shown. This significantly enhances the outcoupling efficiency from 22% (of standard randomly-oriented emitters) to 34% (of face-down oriented emitters) in the LED. As a result, the external quantum efficiency reaches a record high level of 18.1% for the solution-processed type of CQW-LEDs, putting their efficiency performance on par with the hybrid organic-inorganic evaporation-based CQW-LEDs and all other best solution-processed LEDs. This SAM-CQW-LED architecture allows for a high maximum brightness of 19,800 cd m−2 with a long operational lifetime of 247 h at 100 cd m−2 as well as a stable saturated deep-red emission (651 nm) with a low turn-on voltage of 1.7 eV at a current density of 1 mA cm−2 and a high J90 of 99.58 mA cm−2. These findings indicate the effectiveness of oriented self-assembly of CQWs as an electrically-driven emissive layer in improving outcoupling and external quantum efficiencies in the CQW-LEDs.  相似文献   

20.
Electrochemical CO2 reduction reaction (CO2RR) is an effective approach to address CO2 emission, promote recycling, and synthesize high-value multi-carbon (C2+) chemicals for storing renewable electricity in the long-term. The construction of multilayer-bound nanoreactors to achieve management of intermediate CO is a promising strategy for tandem to C2+ products. In this study, a series of Ag@Cu2O nanoreactors consisting of an Ag-yolk and a multilayer confined Cu shell is designed to profile electrocatalytic CO2RR reactions. The optimized Ag@Cu2O-2 nanoreactor exhibits a 74% Faradaic efficiency during the C2+ pathway and remains stable for over 10 h at a bias current density of 100 mA cm−2. Using the finite element method, this model determines that the certain volume of cavity in the Ag@Cu2O nanoreactors facilitates on-site CO retention and that multilayers of Cu species favor CO capture. Density functional theory calculations illustrate that the biased generation of ethanol products may arise from the (100)/(111) interface of the Cu layer. In-depth explorations in multilayer-bound nanoreactors provide structural and interfacial guidance for sequential coupling of CO2RR intermediates for efficient C2+ generation.  相似文献   

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