CO2 Electroreduction Activity Research Articles

0D/1D heterostructure for efficient electrocatalytic CO2-to-C1 conversion by ultra-small cluster-based multi-metallic sulfide nanoparticles and MWCNTs

Rationally constructed catalysts for efficiently converting CO2 into valuable carbonaceous fuels like CO and formate via electrochemical process are promising for decreasing the excessive emission of CO2. Thus, electrocatalysts with a large turnover frequency (TOF) for CO and formate are highly desirable. To this end, multi-metallic nanoclusters (NCs) with unique electronic structure, large specific surface and abundant active sites are favorable theoretically. However, their structural complexity and challenging synthesis impede the application in CO2 electroreduction. Herein, negatively charged multi-metallic sulfide supertetrahedral NCs-based nanoparticles, containing Cu, Ga, In and Sn four metal components, were for the first time electrostatically self-assembled with positively charged multi-walled carbon nanotubes (MWCNTs) to fabricate a novel 0D/1D heterostructure that exhibits efficient CO2 electroreduction to C1 products (CO + HCOOH) with high Faradaic efficiency (FE) (>80%), excellent TOF (5974.62 h−1) and good long-term stability (12 h). Besides, a ratio-tunable syngas (CO + H2) (VCO/VH2: 0.1 ~ 2.73) and efficient electrochemical oxygen reduction reaction (ORR) could also be achieved for the hybrid catalyst. Comparative experiments figured out the favorable synergistic effects of co-existed Ga and In ions and enhanced interfacial charge-transfer were responsible for the promoted CO2 electroreduction activity.

Achieving Highly Efficient Carbon Dioxide Electrolysis by In Situ Construction of the Heterostructure.

The design of active cathode catalysts, with abundant active sites and outstanding catalytic activity for CO2 electroreduction, is important to promote the development of solid oxide electrolysis cells (SOECs). Herein, A-site-deficient perovskite oxide (La0.2Sr0.8)0.9Ti0.5Mn0.4Cu0.1O3-δ (LSTMC) is synthesized and studied as a promising cathode for SOECs. Cu nanoparticles can be rapidly and uniformly in situ-exsolved under reducing conditions. The heterostructure formed by the exsoluted Cu and LSTMC provides abundant active sites for the catalytic conversion of CO2 to CO. Combined with the remarkable oxygen-ion transport capacity of the LSTMC substrate, the specially designed Cu@LSTMC cathode exhibits a dramatically improved electrochemical performance. Furthermore, first-principles calculations proposed a mechanism for the adsorption and activation of CO2 by the heterostructure. Electrochemically, the Cu@LSTMC presents a high current density of 2.82 A cm-2 at 1.8 V and 800 °C, which is about 2.5 times higher than that of LSTM (1.09A cm-2).

Microstructural origin of locally enhanced CO2 electroreduction activity on gold.

Understanding how the bulk structure of a material affects catalysis on its surface is critical to the development of actionable catalyst design principles. Bulk defects have been shown to affect electrocatalytic materials that are important for energy conversion systems, but the structural origins of these effects have not been fully elucidated. Here we use a combination of high-resolution scanning electrochemical cell microscopy and electron backscatter diffraction to visualize the potential-dependent electrocatalytic carbon dioxide [Formula: see text] electroreduction and hydrogen [Formula: see text] evolution activity on Au electrodes and probe the effects of bulk defects. Comparing colocated activity maps and videos to the underlying microstructure and lattice deformation supports a model in which CO2 electroreduction is selectively enhanced by surface-terminating dislocations, which can accumulate at grain boundaries and slip bands. Our results suggest that the deliberate introduction of dislocations into materials is a promising strategy for improving catalytic properties.

Mechanistic study of efficient producing CO2 electroreduction via 2D metal-organic frameworks M3(2,3,6,7,10,11-hexaiminotriphenylene)2 surface

M3(HITP)2 prototype 2D MOFs compounds possess a high catalytic activity for CO2 electroreduction to hydrocarbon fuels at low overpotentials. However, the mechanism path selectivity is still a huge challenge during the production of final product species at low potentials. The transition metal coordinated nitrogen active center of M3(HITP)2 catalysts is identified to strong M-C bound coupling, leading to a high selectivity towards CH3OH, Cr3(HITP)2, and Mn3(HITP)2. Further, it also demonstrates a high efficiency catalytic performance for generating CH4. In addition, linear scaling relations and volcano plot of thermodynamic stability are also investigated and compared, suggesting that some M3(HITP)2 compounds have effective selectivity performance to CO2 reduction reaction (CO2RR). Furthermore, linear scaling relationships and volcano plots between different intermediate species are common descriptors used to identity an excellent catalyst for CO2 electroreduction. In order to get a further exploration of the reaction mechanism pathway and final products for the CO2RR, authors considered all the intermediates. It showed that the most favorable reaction pathway and intermediate species can be determined by the metal-carbon (M-C) or metal-oxygen (M-O) bounds. The reduction of CO2 into CH4 with a high overpotential depends on the thermodynamic rate-determining step (RDS) of the largest limiting potential along the minimum energy path, the electronic structure of these catalysts also plays an important role in the selective CO2RR.

Amorphous urchin-like copper@nanosilica hybrid for efficient CO2 electroreduction to C2+ products

Currently most of research efforts for selective electrocatalysis CO2 reduction to C2+ products have relied on crystalline Cu-based catalysts; amorphous Cu with abundant low-coordinated atoms holds greater promise for this conversion yet remains relatively underexplored. Here we report an amorphous urchin-like Cu@nanosilica hybrid synthesized by electrostatic coupling Si polyanions with Cu salt in hydrothermal processes. The Cu@nanosilica electrocatalyst displays excellent CO2 electroreduction activity and selectivity with a Faradic efficiency of 70.5% for C2+ product production, and higher stability compared to the crystalline Cu counterpart. The solar-driven CO2 electrolysis yields an energy efficiency of 20% for C2+ product production. Mechanism study reveals that the urchin-like Cu@nanosilica catalyst with amorphous Cu/Cu+ dispersion enhances CO2 adsorption and activation to facilitate generation of CO2−* and possible CO* intermediates, and suppresses hydrogen evolution concurrently. The combined effects of both aspects promote efficient C2+ product production from CO2 electroreduction.

An amide-based second coordination sphere promotes the dimer pathway of Mn-catalyzed CO2-to-CO reduction at low overpotential.

The [fac-Mn(bpy)(CO)3Br] complex is capable of catalyzing the electrochemical reduction of CO2 to CO with high selectivity, moderate activity and large overpotential. Several attempts have been made to lower the overpotential and to enhance the catalytic activity of this complex by manipulating the second-coordination sphere of manganese and using relatively stronger acids to promote the protonation-first pathway. We report herein that the complex [fac-Mn(bpy-CONHMe)(CO)3(MeCN)]+ ([1-MeCN]+; bpy-CONHMe = N-methyl-(2,2′-bipyridine)-6-carboxamide) as a pre-catalyst could catalyze the electrochemical reduction of CO2 to CO with low overpotential and high activity and selectivity. Combined experimental and computational studies reveal that the amide NH group not only decreases the overpotential of the Mn catalyst by promoting the dimer and protonation-first pathways in the presence of H2O but also enhances the CO2 electroreduction activity by facilitating C–OH bond cleavage, making [1-MeCN]+ an efficient CO2 reduction pre-catalyst at low overpotential.

Transition metal doped C3N monolayer as efficient electrocatalyst for carbon dioxide electroreduction: A computational study

Recently, two-dimensional graphitic carbon nitrides have emerged as potential electrocatalysts for CO2 electroreduction (CO2ER). Herein, a series of transition metal (M = Mn-Cu, Ru-Ag) doped C3N monolayer (M-C3N) as a novel CO2ER catalyst has been investigated by employing the density functional method. By a careful computational screening, Mn-C3N is identified as the best catalyst for CO2ER, due to its high catalytic activity and high selectivity. HCOOH is the final product with a low overpotential of 0.04 V and a low kinetic energy barrier of 0.75 eV. The hydrogen evolution is also suppressed on Mn-C3N surface. Therefore, the CO2ER activity could be tuned by adjusting the metal atom in the C3N monolayer, which may shed new light on designing novel C3N-based CO2ER catalyst.

CO2 Electroreduction Reaction on Pt-Cu Catalyst and Its in-Situ Analysis By Infrared Spectroscopy

The concentration of CO2 in the atmosphere continues to increase. As a result, global warming is considered to be progressing due to the greenhouse effect. Therefore, the goal of "achieving a balance between human-made emissions of greenhouse gases and removals by sinks in the second half of this century" is set and decreasing the CO2 emissions has become an urgent issue. Recently, it was found that the CO2 electroreduction in an acidic solution on a Pt-based electrode catalyst, such as Pt or PtRu, proceeds at around 0.05 V vs. SHE, which means that CO2 reduction occur with extremely low overvoltage [1]. Our research group has previously reported that a Pt oxide thin film exhibits a higher CO2 electroreduction activity than a Pt one, and the factors affecting the superior CO2 electroreduction activity was considered by Surface-Enhanced Infrared Absorption Spectroscopy (SEIRAS) [2,3]. In this study, CO2 electroreduction activity of Pt and Pt-Cu electrodes were evaluated and its difference was investigated by in-situ SEIRAS.The specimen was a Pt thin film or Pt oxide thin film, which were prepared on a Ti substrate by reactive sputtering. The detailed procedure was described in a previous report. The rotating disk electrode was fabricated from a Ti substrate coated with the Pt thin film or the Pt oxide thin film. It was attached to the electrode rotation system as the working electrode, and the CO2 electroreduction activity was evaluated. The counter electrode and the reference electrode were a Pt sheet and an Ag/AgCl in 3.30 mol dm-3 KCl, respectively. The electrolytic solution was a 0.1 kmol dm-3 HClO4 aqueous solution. For in-situ SEIRAS, the electrocatalysts were supported in Au thin film which was prepared by electroless deposition on a semi-cylindrical Si prism. The resolution of the infrared spectrometer was 4.0 cm-1, and the detector was a liquid nitrogen-cooled MCT detector. The IR spectrum measured at 1.2 V vs. RHE was used as a reference.Fig. 1 shows the cycic voltammograms of the Pt thin film. In Ar-deaerated atmosphere, typical characteristics of Pt was observed. However, the oxidation current was recognized at around 0.6 V vs. SHE in CO2-saturated solution. This anodic peak reflects the CO2 electroreduction activity [2]. Fig. 2 shows the relationship between CO2 electroreduction activities per active surface area and Cu content of the prepared thin films. The CO2 electroreduction activities of the Pt-Cu thin films were higher than that of the Pt thin film. Thus, we used SEIRAS to perform in-situ analysis of the surface adsorption species during the electroreduction to investigate the factors involved in the high electroreduction activity of the Pt Cu electrodes. Fig. 3 shows the Relationship between the intensity of adsorbed linear-CO, HCOO-, and methanol during the CO2 electroreduction reaction on Pt-65.2 at.% Cu/C with time. The potential was maintained at 0.05 V vs. RHE for the CO2 electroreduction to occur. The peaks of the linear-CO and methanol increase with an increase in time. This indicates the amount of linear-CO and methanol adsorbed on the surface was increasing. On the other hand, for HCOO-, although peaks were observed, the absorbance was obviously lower than that for CO. These behaviors were the same as for Pt [3]. Therefore, the difference of CO2 electroreduction activity between Pt and Pt-Cu is not related to the intermediate product and adsorption species. Fig. 4 shows the CO coverage of Pt/C and Pt-65.2at.% Cu/C estimated by CO-stripping voltammetry. Although almost all the surface of Pt was covered by CO, about half of the surface of Pt-Cu maintained clean condition. Therefore, we can say that the better CO2 electroreduction activities of Pt-Cu electrodes are brought by a weak adsorption characteristic of CO.[1] S. Shironita, K. Sato, K. Yoshitake, and M. Umeda, Electrochim. Acta, 206, 254 (2016).[2] K. Ohkubo, H. Takahashi, and M. Taguchi, J. MMIJ, 135(2), 8 (2019).[3] K. Ohkubo, H Takahashi, E.P.J. Watters, and M Taguchi, Electrochemistry, 88(3), 210 (2020). Figure 1

Employing Non-Noble Metals as Catalysts for CO2 Electroreduction

CO2 electroreduction to fuels is one of the most viable solutions for tackling both issues of global warming and energy crises. It is due to the fact that products such as formic acid, methanol, etc. which are obtained by electroreduction of CO2 could be employed as hydrogen carriers or directly as fuels. This phenomenon attracts huge research towards the process and its bottlenecks for making it commercial. The major hurdles regarding catalysis of CO2 electroreduction process are low solubility of CO2 in aqueous solutions and low product yields. In our previous works, we have already demonstrated employment of gas diffusion electrodes for non–noble metal catalysts such as Pb, Bi and Sn. The usage of gas diffusion electrodes enables us to exploit three phase contact of CO2 gas – solid catalysts – liquid electrolyte and shows higher product (formate ion) yield. Additionally, we have also shown through another work that the ternary eutectics of these three non–metal catalysts employed exhibits higher activity for CO2 electroreduction than singular pure metals or any other binary or ternary alloyed compositions of metals. In this work, we want to exploit the conclusions from both the works and subject ternary alloy composition of Pb – Bi – Sn metals in gas diffusion electrode configuration for the process of CO2 electroreduction. Based on the previous two results, author believes that this would enable us to obtain higher product yield and hence better energy efficiency which would be a step forward towards sustainable development.

Employing Non-Noble Metals As Catalysts for CO2 Electroreduction

CO2 electroreduction to fuels is one of the most viable solutions for tackling both the issues of global warming and energy crises. It is due to the fact that the products such as formic acid, methanol, etc. which are obtained by electroreduction of CO2 could be employed as hydrogen carriers or directly as fuels. This phenomenon attracts huge research towards the process and its bottlenecks for making it commercial. The major hurdles regarding catalysis of CO2 electroreduction process are low solubility of CO2 in aqueous solutions and low product yields.In our previous works, we have already demonstrated the employment of gas diffusion electrodes for non – noble metal catalysts such as Pb, Bi and Sn. The usage of gas diffusion electrodes enables us to exploit the three phase contact of CO2 gas – solid catalysts – liquid electrolyte and shows higher product (formate ion) yield.[1] Additionally, we have also shown through another work that the ternary eutectics of these three non – metal catalysts employed exhibits higher activity for CO2 electroreduction than singular pure metals or any other binary or ternary alloyed compositions of the metals.[2] In this work, we want to exploit the conclusions from both the works and subject ternary alloy composition of Pb – Bi – Sn metals in gas diffusion electrode configuration for the process of CO2 electroreduction. Based on the previous two results, author believes that this would enable us to obtain higher product yield and hence better energy efficiency which would be a step forward towards sustainable development.Reference:[1] A. S. Kumawat and A. Sarkar (2017), Comparative study of carbon supported Pb, Bi and Sn catalysts for electroreduction of carbon dioxide in alkaline medium, Journal of Electrochemical Society, 164 (14), H1112 – H1120. doi: 10.1149/2.0991714jes[2] A. S. Kumawat and A. Sarkar (2019), Electrochemical reduction of CO2 on Pb – Bi – Sn metal mixtures – Importance of Eutectics, SN Applied Sciences 1: 301. doi: 10.1007/s42452-019-0313-y

Unprecedented Lower Over-potential for CO2 Electro-reduction on Copper oxide Anchored to Graphene Oxide Microstructures

Efficient conversion of CO2 into chemical feedstock and fuels via electrochemical carbon dioxide reduction reaction (ECO2R) has perpetuated ambitious and broad research interests. Herein, we report the design and synthesis of copper oxide anchored to graphene oxide (Cu/CuxO.GO) porous microstructures via a simple and atom-economical DC electrophoresis approach that exhibit excellent electro-catalytic activity toward ECO2R. A systematic rationalisation of the several physico-chemical parameters associated with the fabrication of porous Cu/CuxO.GO network, viz. composition, the extent of defects in GO and the proportion of oxide contents in Cu/CuxO was explored to understand their impact on the electro-catalytic activity of copper plus GO-based composites. The porous and asymmetric Cu/CuxO.GO nano-composite with optimised oxide content, and metal-GO interactions exhibit an excellent activity for CO2 electroreduction into CO and ethane with a respective Faradaic efficiency (F.E.) of ca. 40% and 4% at an applied potential of just -0.28 V (vs NHE) in a CO2 saturated acetonitrile solution. Comparison of the overpotential specific F.E. values with the ones reported for similar investigations suggests that the electro-catalytic performance of the Cu/CuxO.GO network is significantly better than that observed for various state of the art electro-catalysts recently designed for the ECO2R.

The critical role of hydride (H−) ligands in electrocatalytic CO2 reduction to HCOOH by [Cu25H22(PH3)12]Cl nanocluster

Copper is the prototype metal to produce hydrocarbons from CO2 electroreduction, however, rationale of the catalytic mechanism by copper nanoparticles has been severely impeded due to structural polydispersity. The recent efforts in the synthesis of nanosized copper clusters open up new opportunities for atomic-level understanding of the catalytic mechanism. Herein, we considered [Cu25H22(PH3)12]Cl cluster, bearing the highest ratio of hydride ligands, as a test model to examine its activity for CO2 electroreduction. Our DFT calculations showed that both the surface Cu and the hydride ligands are actively participated in the hydrogenation reactions and selectively reduce CO2 to HCOOH via the proton-reduction channel and the hydride-proton channel, as opposed to the commonly produced CO on copper surface/nanoparticles. We also evaluated the competitive HER activity, and found that H2 evolution requires higher barrier than HCOOH. Our studies highlight the important role of hydrides in directing the activity and selectivity for CO2 electroreduction.

Selective electrocatalytic reduction of carbon dioxide to oxalate by lead tin oxides with low overpotential

Carbon dioxide electroreduction to oxalate suffers from low selectivity and large overpotential. This study used lead tin oxide nanoparticles for selective oxalate generation with low overpotential in propylene carbonate. The maximum Faradaic efficiency of 85.1 % have been reached by PbSnO3/C at −1.9 V vs Ag/Ag+ with oxalate current density of 2.0 mA/cm2 on carbon fiber paper. The notable activity for CO2 electroreduction to oxalate was attributed to the synergistic effect of partially reduced Pb and oxidized SnOx composites in lead tin oxides.

Boosting carbon dioxide electroreduction to C1 feedstocks via theory-guided tailoring oxygen defects in porous tin-oxide nanocubes

Metal-oxide catalysts have great potential in efficient CO2 electroreduction (CO2ER). Unfortunately, many catalysts exhibit limited selectivity for carbon products at the high current density. Here, density functional theory is applied to analyzethe active sites on SnO2 matrix surface. The theoretical analysis indicates that the elimination of oxygen atoms from SnO2 matrix can significantly improve CO2 activation and suppress H2. Inspired by the analysis, a series of defect-engineered SnO2 nanocubes are synthesized. The as-prepared SnO2 with rich oxygen vacancy (Vo-rich SnO2) possesses C1 selectivity of 92.5% at −44.2 mA cm−2 which is higher than pristine SnO2 (78.1% at −18.2 mA cm−2), and reaches 30 h stability. Furthermore, the CO2ER activity in a 10% CO2 atmosphere is studied for the first time, where Vo-rich SnO2 demonstrates C1 selectivity of 74.5%. This work testifies the potential of theory-guided strategy to design practicaltin-oxide electrocatalysts and firstly highlights the research of industrial flue gas for CO2ER.

Metal-support interaction enhanced electrochemical reduction of CO2 to formate between graphene and Bi nanoparticles

Metal nanoparticles stabilized on a support material have been explored extensively to boost heterogeneous catalysis. Herein, the effect of metal-support interaction between bismuth (Bi) nanoparticles and reduced graphene oxide nanosheets (Gr) on the electroreduction of CO2 towards value-added formate is explored. The obtained Bi/Gr hybrid catalysts exhibit a superior catalytic activity towards electrochemical reduction of CO2, which gives the maximum faradic efficiency of 92.1 % at -0.97 V (vs. RHE) for formate generation. Particularly, the hydride shows an enhancement to the catalysts of bare Bi and physical mixture of Bi and Gr, with a high current density of 28.1 mA∙cm−2 and production rate of 0.53 mol∙cm−2 h-1 at -1.17 V (vs. RHE) for formate generation. The electrochemical analysis reveals that the metal-support interactions substantially boost CO2 electroreduction activity through modification the electronic structure and improving interfacial electron transfer between Bi and Gr. This work not only deepens an understanding of metal-support interaction effect but also sheds light on the design of high-efficiency catalysts toward CO2 electroreduction by virtue of the interactions between active metals and carbon-like support.

Engineering Electronic Structure of Stannous Sulfide by Amino‐Functionalized Carbon: Toward Efficient Electrocatalytic Reduction of CO2 to Formate

AbstractEngineering electronic structure to enhance the binding energies of reaction intermediates in order to achieve a high partial current density can lead to increased yield of target products. Herein, amino‐functionalized carbon is used to regulate the electronic structure of tin‐based catalysts to enhance activity of CO2 electroreduction. The hollow nanotubes composed of SnS (stannous sulfide) nanosheets are modified with amino‐functionalized carbon layers, achieving a highest formate Faraday efficiency of 92.6% and a remarkable formate partial current density of 41.1 mA cm−2 (a total current density of 52.1 mA cm−2) at a moderate overpotential of 0.9 V versus reversible hydrogen electrode, as well as a good stability. Density functional theory calculations demonstrate that the superior activity is attributed to the synergistic effect among SnS and Aminated‐C in increasing the adsorption energies of the key intermediates and accelerating the charge transfer rate.

Hierarchical heterostructure of SnO2 confined on CuS nanosheets for efficient electrocatalytic CO2 reduction.

The direct electroreduction of CO2 to ratio-tunable syngas (CO + H2) is an appealing solution to provide important feedstocks for many industrial processes. However, low-cost, Earth-abundant yet efficient and stable electrocatalysts for composition-adjustable syngas have still not been realized for practical applications. Herein, new hierarchical 0D/2D heterostructures of SnO2 nanoparticles (NPs) confined on CuS nanosheets (NSs) were designed to enable CO2 electroreduction to a wide-range syngas (CO/H2: 0.11-3.86) with high faradaic efficiency (>85%), remarkable turnover frequency (96.12 h-1) and excellent durability (over 24 h). Detailed experimental characterization studies together with theoretical calculations manifest that the ascendant catalytic performance is not only attributed to the heterostructure of ultrasmall SnO2 NPs homogeneously confined on ultrathin CuS NSs, which endows the maximum exposure of active sites and faster charge transfer, but is also accounted by the strong interaction between well-defined SnO2 and CuS interfaces, which modulated reaction free-energies of reaction intermediates and hence improved the activity of CO2 electroreduction to highly ratio-tunable syngas. This work provides a better understanding and a new strategy for intermediate regulation by interface engineering of hereostructures for CO2 reduction and beyond.

Rational design of dual-metal-site catalysts for electroreduction of carbon dioxide

Dual-metal-site catalysts could exhibit superior activity for CO2 electroreduction to CO due to the breaking of scaling relationship.

Ensemble Effect in Bimetallic Electrocatalysts for CO2 Reduction.

Alloying is an important strategy for the design of catalytic materials beyond pure metals. The conventional alloy catalysts however lack precise control over the local atomic structures of active sites. Here we report on an investigation of the active-site ensemble effect in bimetallic Pd-Au electrocatalysts for CO2 reduction. A series of Pd@Au electrocatalysts are synthesized by decorating Au nanoparticles with Pd of controlled doses, giving rise to bimetallic surfaces containing Pd ensembles of various sizes. Their catalytic activity for electroreduction of CO2 to CO exhibits a nonlinear behavior in dependence of the Pd content, which is attributed to the variation of Pd ensemble size and the corresponding tuning of adsorption properties. Density functional theory calculations reveal that the Pd@Au electrocatalysts with atomically dispersed Pd sites possess lower energy barriers for activation of CO2 than pure Au and are also less poisoned by strongly binding *CO intermediates than pure Pd, with an intermediate ensemble size of active sites, such as Pd dimers, giving rise to the balance between these two rate-limiting factors and achieving the highest activity for CO2 reduction.

Nitrogen doped MoS2 and nitrogen doped carbon dots composite catalyst for electroreduction CO2 to CO with high Faradaic efficiency

CO2 utilization by direct electroreduction offers an attractive route for preparing valuable chemicals or alternative liquid fuels, and mitigating the hazardous effects of global warming. Unfortunately, the electroreduction CO2 currently suffers from poor efficiency, low produce selectivity, and large overpotential is required to initiate CO2 reduction due to the thermodynamic stability of CO2. Therefore, the development of low-cost transition-metal chalcogenides electrocatalysts for high selectivity electroreduction CO2 under considerably low overpotentials are still challenge, due to its high catalytic activity of hydrogen evolution reaction and poor electronic conductivity. Herein, for the first time, N-doped MoS2 nanosheets and N-doped carbon nanodots (N-MoS2@NCDs) composite was successfully prepared by solvothermal method in the presence of E-MoS2 and DMF solvent. During solvothermal process, N atoms were introduced into MoS2 framework and N-doped CDs were formed on the surface of MoS2 nanosheets at the same time. The optimized N-MoS2@NCDs-180 for electroreduction CO2 displayed a high CO Faradaic efficiency up to 90.2% and a low onset overpotential requirement of 130 mV for CO formation, which were significantly superior to those of the E-MoS2 and other previously reported transition-metal sulfides electrocatalysts. The experiment verified that the N-doped CDs on the surface MoS2 provided a good electrical conductivity, which accelerated electron transport. Moreover, DFT theoretical calculation demonstrated that the N doping into MoS2 could decrease the energy barrier of the COOH* intermediate formation and create more electrons on the edge Mo of N-MoS2, thereby enhancing catalytic activity of CO2 electroreduction to CO.