A New Strategy for Accelerating Dynamic Proton Transfer of Electrochemical CO2 Reduction at High Current Densities

Developing single-atom electrocatalysts with high activity and superior selectivity at a wide potential window for CO₂ reduction reaction (CO₂RR) still remains a great challenge. Herein, a porous Ni N C catalyst containing atomically dispersed Ni N₄ sites and nanostructured zirconium oxide (ZrO₂@Ni-NC) synthesized via a post-synthetic coordination coupling carbonization strategy is reported. The as-prepared ZrO₂@Ni-NC exhibits an initial potential of −0.3 V, maximum CO Faradaic efficiency (F.E.) of 98.6% ± 1.3, and a low Tafel slope of 71.7 mV dec⁻¹ in electrochemical CO₂RR. In particular, a wide potential window from −0.7 to −1.4 V with CO F.E. of above 90% on ZrO₂@Ni-NC far exceeds those of recently developed state-of-the-art CO₂RR electrocatalysts based on Ni N moieties anchored carbon. In a flow cell, ZrO₂@Ni-NC delivers a current density of 200 mA cm⁻² with a superior CO selectivity of 96.8% at −1.58 V in a practical scale. A series of designed experiments and structural analyses identify that the isolated Ni N₄ species act as real active sites to drive the CO₂RR reaction and that the nanostructured ZrO₂ largely accelerates the protonation process of *CO₂⁻ to *COOH intermediate, thus significantly reducing the energy barrier of this rate-determining step and boosting whole catalytic performance.     

Atomically Defined Undercoordinated Active Sites for Highly Efficient CO2 Electroreduction

Electrocatalytic reduction of carbon dioxide (CO₂ER) in rechargeable Zn–CO₂ battery still remains a great challenge. Herein, a highly efficient CO₂ER electrocatalyst composed of coordinatively unsaturated single‐atom copper coordinated with nitrogen sites anchored into graphene matrix (Cu–N₂/GN) is reported. Benefitting from the unsaturated coordination environment and atomic dispersion, the ultrathin Cu–N₂/GN nanosheets exhibit a high CO₂ER activity and selectivity for CO production with an onset potential of ?0.33 V and the maximum Faradaic efficiency of 81% at a low potential of ?0.50 V, superior to the previously reported atomically dispersed Cu–N anchored on carbon materials. Experimental results manifest the highly exposed and atomically dispersed Cu–N₂ active sites in graphene framework where the Cu species are coordinated by two N atoms. Theoretical calculations demonstrate that the optimized reaction free energy for Cu–N₂ sites to capture CO₂ promote the adsorption of CO₂ molecules on Cu–N₂ sites; meanwhile, the short bond lengths of Cu–N₂ sites accelerate the electron transfer from Cu–N₂ sites to *CO₂, thus efficiently boosting the *COOH generation and CO₂ER performance. A designed rechargeable Zn–CO₂ battery with Cu–N₂/GN nanosheets deliver a peak power density of 0.6 mW cm^?2, and the charge process of battery can be driven by natural solar energy.     

Highly Dispersed NiO Clusters Induced Electron Delocalization of Ni?N?C Catalysts for Enhanced CO2 Electroreduction

Oxygen-regulated Ni-based single-atom catalysts (SACs) show great potential in accelerating the kinetics of electrocatalytic CO₂ reduction reaction (CO₂RR). However, it remains a challenge to precisely control the coordination environment of Ni O moieties and achieve high activity at high overpotentials. Herein, a facile carbonization coupled oxidation strategy is developed to mass produce NiO clusters-decorated Ni N C SACs that exhibit a high Faradaic efficiency of CO (maximum of 96.5%) over a wide potential range (−0.9 to −1.3 V versus reversible hydrogen electrode) and a high turnover frequency for CO production of 10 120 h⁻¹ even at the high overpotential of 1.19 V. Density functional theory calculations reveal that the highly dispersed NiO clusters induce electron delocalization of active sites and reduce the energy barriers for *COOH intermediates formation from CO₂, leading to an enhanced reaction kinetics for CO production. This study opens a new universal pathway for the construction of oxygen-regulated metal-based SACs for various catalytic applications.     

Identifying Active Sites of Nitrogen‐Doped Carbon Materials for the CO2 Reduction Reaction

Nitrogen‐doped carbon materials are proposed as promising electrocatalysts for the carbon dioxide reduction reaction (CRR), which is essential for renewable energy conversion and environmental remediation. Unfortunately, the unclear cognition on the CRR active site (or sites) hinders further development of high‐performance electrocatalysts. Herein, a series of 3D nitrogen‐doped graphene nanoribbon networks (N‐GRW) with tunable nitrogen dopants are designed to unravel the site‐dependent CRR activity/selectivity. The N‐GRW catalyst exhibits superior CO₂ electrochemical reduction activity, reaching a specific current of 15.4 A g_catalyst^?1 with CO Faradaic efficiency of 87.6% at a mild overpotential of 0.49 V. Based on X‐ray photoelectron spectroscopy measurements, it is experimentally demonstrated that the pyridinic N site in N‐GRW serves as the active site for CRR. In addition, the Gibbs free energy calculated by density functional theory further illustrates the pyridinic N as a more favorable site for the CO₂ adsorption, *COOH formation, and *CO removal in CO₂ reduction.     

Hydroxypillar[5]arene-Confined Silver Nanocatalyst for Selective Electrochemical Reduction of CO2 to Ethanol

CO is usually the dominant product on silver-based catalysts in electrochemical CO₂ reduction reaction (CO₂RR) possibly due to weak *CO adsorption. In this report, a hydroxypillar[5]arene-extended porous polymer-confined silver catalyst (PAF-PA5-Ag-0.8) for electrochemical CO₂RR which can selectively produce ethanol with a maximum Faradaic efficiency of 55% at 11 mA cm⁻¹ is described. The study reveals that the hydroxypillar[5]arene-confined Ag clusters are the active sites for ethanol formation. Moreover, temperature-programmed desorption measurements demonstrate an enhanced adsorption strength of CO* on PAF-PA5-Ag-0.8 compared with that on commercial Ag nanoparticles, which is favored by the C-C coupling to form ethanol. The density functional theory study indicates that the confined Ag clusters in PAF-PA5-Ag-0.8 contribute to high C₂ selectivity in CO₂RR through facilitating *COOH formation, stabilizing *CO intermediates, and inhibiting hydrogen evolution. This work provides a new design strategy by modulating *CO adsorption strength on non-copper electrocatalysts in converting CO₂ into “green” C₂ products.     

Molecular Modulation of Sequestered Copper Sites for Efficient Electroreduction of Carbon Dioxide to Methane

The sustainable production of methane (CH₄) via the electrochemical conversion of carbon dioxide (CO₂) is an appealing approach to simultaneously mitigating carbon emissions and achieving energy storage in chemical bonds. Copper (Cu) is a unique material to produce hydrocarbons and oxygenates. However, selective methane generation on Cu remains a great challenge due to the preferential *CO dimerization pathway toward multi-carbon (C₂₊) products at neighboring catalytic sites. Herein, a conjugated copper phthalocyanine polymer (CuPPc) is designed by a facile solid-state method for highly selective CO₂-to-CH₄ conversion. The spatially isolated Cu N₄ sites in CuPPc favor the *CO protonation to generate the key *CHO intermediate, thus significantly promoting the formation of CH₄. As a result, the CuPPc catalyst exhibits a high CH₄ Faradaic efficiency of 55% and a partial current density of 18 mA cm⁻² at −1.25 V versus the reversible hydrogen electrode. It also stably operates for 12 h. This study may offer a new solution to regulating the chemical environment of the active sites for the development of highly efficient copper-based catalysts for electrochemical CO₂ reduction.     

Nanostructured β‐Bi2O3 Fractals on Carbon Fibers for Highly Selective CO2 Electroreduction to Formate

3D Bi₂O₃ fractal nanostructures (f‐Bi₂O₃) are directly self‐assembled on carbon fiber papers (CFP) using a scalable hot‐aerosol synthesis strategy. This approach provides high versatility in modulating the physiochemical properties of the Bi₂O₃ catalyst by a tailorable control of its crystalline size, loading, electron density as well as providing exposed stacking of the nanomaterials on the porous CFP substrate. As a result, when tested for electrochemical CO₂ reduction reactions (CO₂RR), these f‐Bi₂O₃ electrodes demonstrate superior conversion of CO₂ to formate (HCOO^?) with low onset overpotential and a high mass‐specific formate partial current density of ?52.2 mA mg^?1, which is ≈3 times higher than that of the drop‐casted control Bi₂O₃ catalyst (?15.5 mA mg^?1), and a high Faradaic efficiency (FE_HCOO^?) of 87% at an applied potential of ?1.2 V versus reversible hydrogen electrode. The findings reveal that the high exposure of roughened β‐phase Bi₂O₃/Bi edges and the improved electron density of these fractal structures are key contributors in attainment of high CO₂RR activity.     

Hierarchical Cross-Linked Carbon Aerogels with Transition Metal-Nitrogen Sites for Highly Efficient Industrial-Level CO2 Electroreduction

Developing highly efficient carbon aerogels (CA) electrocatalysts based on transition metal-nitrogen sites is critical for the CO₂ electroreduction reaction (CO₂RR). However, simultaneously achieving a high current density and high Faradaic efficiency (FE) still remains a big challenge. Herein, a series of unique 3D hierarchical cross-linked nanostructured CA with metal-nitrogen sites (M N, M = Ni, Fe, Co, Mn, Cu) is developed for efficient CO₂RR. An optimal CA/N-Ni aerogel, featured with unique hierarchical porous structure and highly exposed M-N sites, exhibits an unusual CO₂RR activity with a CO FE of 98% at −0.8 V. Notably, an industrial current density of 300 mA cm⁻² with a high FE of 91% is achieved on CA/N-Ni aerogel in a flow-cell reactor, which outperforms almost all previously reported M-N/carbon based catalysts. The CO₂RR activity of different CA/N-M aerogels can be arranged as Ni, Fe, Co, Mn, and Cu from high to low. In situ spectroelectrochemistry analyses validate that the rate-determining step in the CO₂RR is the formation of *COOH intermediate. A Zn CO₂ battery is further assembled with CA/N-Ni as the cathode, which shows a maximum power density of 0.5 mW cm⁻² and a superior rechargeable stability.     

Highly Boosted Reaction Kinetics in Carbon Dioxide Electroreduction by Surface-Introduced Electronegative Dopants

Effectively improving the selectivity while reducing the overpotential over the electroreduction of CO₂ (CO₂ER) has been challenging. Herein, electronegative N atoms and coordinatively unsaturated Ni N₃ moieties co-anchored carbon nanofiber (Ni N₃ NCNFs) catalyst via an integrated electrospinning and carbonization strategy are reported. The catalyst exhibits a maximum CO Faradaic efficiency (F.E.) of 96.6%, an onset potential of −0.3 V, and a low Tafel slope of 71 mV dec⁻¹ along with high stability over 100 h. Aberration corrected scanning transmission electron microscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy identify the atomically dispersed Ni N₃ sites with Ni atom bonded by three pyridinic N atoms. The existence of abundant electronegative N dopants adjoin the Ni N₃ centers in Ni N₃ NCNFs. Theoretical calculations reveal that both, the undercoordinated Ni N₃ centers and their first neighboring C atoms modified by extra N dopants, display the positive effect on boosting CO₂ adsorption and water dissociation processes, thus accelerating the CO₂ER kinetics process. Furthermore, a designed Zn CO₂ battery with the cathode of Ni N₃ NCNFs delivers a maximum power density of 1.05 mW cm⁻² and CO F.E. of 96% during the discharge process, thus providing a promising approach to electric energy output and chemical conversion.     

Selenium‐Doped Hierarchically Porous Carbon Nanosheets as an Efficient Metal‐Free Electrocatalyst for CO2 Reduction

Electrochemical carbon dioxide reduction reaction (CO₂RR) provides a promising pathway for both decreasing atmospheric CO₂ concentration and producing valuable carbon‐based fuels. To explore efficient and cost‐effective catalysts for electrochemical CO₂RR is of great importance, but remains challenging. Se‐doped carbon nanosheets (Se‐CNs) with a micro‐, meso‐, and macroporous structure are proposed for electrochemical CO₂RR. Such an electrocatalyst combines the advantages of Se optimized active sites, hierarchical pores for facilitating reactant or ion penetration, transport and reaction, and large surface area for more accessible active sites. This Se‐CNs electrocatalyst exhibits over 11‐times enhanced partial current density of CO than the CNs without Se doping and high selectivity (90%) for CO₂ electroreduction to CO at a low potential of ?0.6 V versus the reversible hydrogen electrode (vs RHE). Density function theoretical calculations reveal that the Se introduction in CNs lowers the free energy barrier of CO₂RR and inhibits hydrogen evolution reaction effectively, thus improving the selectivity for CO₂ reduction to CO. This work presents a new member of the metal‐free electrocatalyst family, which is easily prepared, low cost, adjustable, and highly efficient for CO₂RR.     

Fe?N4O?C Nanoplates Covalently Bonding on Graphene for Efficient CO2 Electroreduction and Zn?CO2 Batteries (Adv. Funct. Mater. 27/2023)

Electrochemical carbon dioxide (CO₂) reduction into value-added products holds great promise in moving toward carbon neutrality but remains a grand challenge due to lack of efficient electrocatalysts. Herein, the nucleophilic substitution reaction is elaborately harnessed to synthesize carbon nanoplates with a Fe N₄O configuration anchored onto graphene substrate (Fe N₄O C/Gr) through covalent linkages. Density functional theory calculations demonstrate the unique configuration of Fe N₄O with one oxygen (O) atom in the axial direction not only suppresses the competing hydrogen evolution reaction, but also facilitates the desorption of *CO intermediate compared with the commonly planar single-atomic Fe sites. The Fe N₄O C/Gr shows excellent performance in the electroreduction of CO₂ into carbon monoxide (CO) with an impressive Faradaic efficiency of 98.3% at −0.7 V versus reversible hydrogen electrode (RHE) and a high turnover frequency of 3511 h⁻¹. Furthermore, as a cathode catalyst in an aqueous zinc (Zn)-CO₂ battery, the Fe N₄O C/Gr achieves a high CO Faradaic efficiency (≈91%) at a discharge current density of 3 mA cm⁻² and long-term stability over 74 h. This work opens up a new route to simultaneously modulate the geometric and electronic structure of single-atomic catalysts toward efficient CO₂ conversion.     

Nanoscale Management of CO Transport in CO2 Electroreduction: Boosting Faradaic Efficiency to Multicarbon Products via Nanostructured Tandem Electrocatalysts

Tandem catalysis presents a promising strategy to improve the selectivity toward multicarbon products in the electrocatalytic carbon dioxide reduction reaction (CO₂RR). For CO₂RR, CO is a critical intermediate for producing multicarbon products. However, the management of CO localization and CO diffusion remains underexplored despite its critical role. Herein, a 3D tandem catalyst electrode with silver nanoparticles (Ag NPs) is designed to generate CO as an intermediate product within a copper (Cu) nanoneedle array. Via this nanostructured design, CO₂ forms C²⁺ products with a high Faradaic efficiency (FEC²⁺) of 64% in an H-cell and 70% in a flow cell with a current density of 350 mA cm⁻². These figures-of-merit are currently among the top literature reports. More importantly, in situ Raman spectroscopy and finite-element method calculations are employed to elucidate the origins of enhanced selectivity. These approaches reveal the crucial role of prolonging the CO diffusion path length for improving CO utilization during CO₂ conversion with tandem catalyst systems. The favorable CO2RR FEC²⁺ in two distinct environments (H-cell and flow cell) further corroborates that this effect is not limited to a particular reactor environment. Overall, this study provides new insights for designing tandem catalysts for improved CO₂RR selectivity to C²⁺ products.     

1D SnO2 with Wire‐in‐Tube Architectures for Highly Selective Electrochemical Reduction of CO2 to C1 Products

Electrochemical reduction of CO₂ (ERC) into useful products, such as formic acid and carbon monoxide, is a fascinating approach for CO₂ fixation as well as energy storage. Sn‐based materials are attractive catalysts for highly selective ERC into C₁ products (including HCOOH and CO), but still suffer from high overpotential, low current density, and poor stability. Here, One‐dimensional (1D) SnO₂ with wire‐in‐tube (WIT) structure is synthesized and shows superior selectivity for C₁ products. Using the WIT SnO₂ as the ERC catalyst, very high Faradaic efficiency of C₁ products (>90%) can be achieved at a wide potential range from ?0.89 to ?1.29 V versus RHE, thus substantially suppressing the hydrogen evolution reaction. The electrocatalyst also exhibits excellent long‐term stability. The improved catalytic activity of the WIT SnO₂ over the commercial SnO₂ nanoparticle indicates that higher surface area and large number of grain boundaries can effectively enhance the ERC activity. Synthesized via a facile and low‐cost electrospinning technology, the reduced WIT SnO₂ can serve as a promising electrocatalyst for efficient CO₂ to C₁ products conversion.     

Enhanced Charge Transfer Kinetics for the Electroreduction of Carbon Dioxide on Silver Electrodes Functionalized with Cationic Surfactants

Cationic ammonium surfactants can be used together with a suitable catalyst to enhance the electroreduction of carbon dioxide (CO₂RR). However, the underlying reasons for the improvements are not yet well understood. In this study, it is shown that didodecyldimethylammonium bromide (DDAB; [(C₁₂H₂₅)₂N(CH₃)₂]Br), when added to the catholyte, can increase the rate of CO₂ reduction to CO on silver electrodes by 12-fold at −0.9 V versus reversible hydrogen electrode. More importantly, electrochemical impedance spectroscopy revealed that DDAB lowers the charge transfer resistance (R_CT) for CO₂RR on silver, and these changes can be correlated with enhancements in partial current densities of CO. Interestingly, when DDAB is added onto two other CO-producing metals, namely, zinc and gold, the CO₂RR charge transfer kinetics are improved only on Zn, but not on Au electrodes. By means of a semiempirical model combining density functional theory calculations and experimental data, it is concluded that DDAB generally strengthens the adsorption energies of the *COOH intermediate, which leads to enhanced CO production on silver and zinc, but not on gold.     

Accelerating CO2 Electroreduction to CO Over Pd Single‐Atom Catalyst

The electrochemical conversion of carbon dioxide (CO₂) into value‐added chemicals is regarded as one of the promising routes to mitigate CO₂ emission. A nitrogen‐doped carbon‐supported palladium (Pd) single‐atom catalyst that can catalyze CO₂ into CO with far higher mass activity than its Pd nanoparticle counterpart, for example, 373.0 and 28.5 mA mg^?1_Pd, respectively, at ?0.8 V versus reversible hydrogen electrode, is reported. A combination of in situ X‐ray characterization and density functional theory (DFT) calculation reveals that the Pd? N₄ site is the most likely active center for CO production without the formation of palladium hydride (PdH), which is essential for typical Pd nanoparticle catalysts. Furthermore, the well‐dispersed Pd? N₄ single‐atom site facilitates the stabilization of the adsorbed CO₂ intermediate, thereby enhancing electrocatalytic CO₂ reduction capability at low overpotentials. This work provides important insights into the structure‐activity relationship for single‐atom based electrocatalysts.     

Pre-Activation of CO2 at Cobalt Phthalocyanine-Mg(OH)2 Interface for Enhanced Turnover Rate

Cobalt phthalocyanine (CoPc) anchored on heterogeneous scaffold has drawn great attention as promising electrocatalyst for carbon dioxide reduction reaction (CO₂RR), but the molecule/substrate interaction is still pending for clarification and optimization to maximize the reaction kinetics. Herein, a CO₂RR catalyst is fabricated by affixing CoPc onto the Mg(OH)₂ substrate primed with conductive carbon, demonstrating an ultra-low overpotential of 0.31 ± 0.03 V at 100 mA cm⁻² and high faradaic efficiency of >95% at a wide current density range for CO production, as well as a heavy-duty operation at 100 mA cm⁻² for more than 50 h in a membrane electrode assembly. Mechanistic investigations employing in situ Raman and attenuated total reflection surface-enhanced infrared absorption spectroscopy unravel that Mg(OH)₂ plays a pivotal role to enhance the CO₂RR kinetics by facilitating the first-step electron transfer to form anionic *CO₂⁻ intermediates. DFT calculations further elucidate that introducing Lewis acid sites help to polarize CO₂ molecules absorbed at the metal centers of CoPc and consequently lower the activation barrier. This work signifies the tailoring of catalyst-support interface at molecular level for enhancing the turnover rate of CO₂RR.     

In Situ Structure Refactoring of Bismuth Nanoflowers for Highly Selective Electrochemical Reduction of CO2 to Formate

The electrocatalytic CO₂ reduction reaction (CO₂RR) has been considered a promising route toward carbon neutrality and renewable energy conversion. At present, most bismuth (Bi) based electrocatalysts are adopted to reduce CO₂ to formate (HCOOH). However, the mechanism of different Bi nanostructures on the electrocatalytic performance requires more detailed exposition. Herein, a combined chemical replacement and electrochemical reduction process is reported to realize in situ morphology reconstruction from Bi@Bi₂O₃ nanodendrites (Bi@Bi₂O₃-NDs) to Bi nanoflowers (Bi-NFs). The Bi@Bi₂O₃-NDs are proven to undergo a two-step transformation process to form Bi-NFs, aided by Bi₂O₂CO₃ as the intermediate in KHCO₃ solution. Extensive surface reconstruction of Bi@Bi₂O₃-NDs renders the realization of tailored Bi-NFs electrocatalyst that maximize the number of exposed active sites and active component (Bi⁰), which is conducive to the adsorption and activation of CO₂ and accelerated electron transfer process. The as-prepared Bi-NFs exhibit a Faradaic efficiency (FE_formate) of 92.3% at −0.9 V versus RHE and a high partial current density of 28.5 mA cm⁻² at −1.05 V versus RHE for the electroreduction of CO₂ to HCOOH. Moreover, the reaction mechanism is comprehensively investigated by in situ Raman analysis, which confirms that *OCHO is a key intermediate for the formation of HCOOH.     

Cobalt−Iron Oxide Nanosheets for High‐Efficiency Solar‐Driven CO2−H2O Coupling Electrocatalytic Reactions

Solar‐driven electrochemical overall CO₂ splitting (OCO₂S) offers a promising route to store sustainable energy; however, its extensive implementation is hindered by the sluggish kinetics of two key reactions (i.e., CO₂ reduction reaction and oxygen evolution reaction (CO₂RR and OER, respectively)). Here, as dual‐functional catalysts, Co₂FeO₄ nanosheet arrays having high electrocatalytic activities toward CO₂RR and OER are developed. When the catalyst is applied to a complete OCO₂S system driven by a triple junction GaInP₂/GaAs/Ge photovoltaic cell, it shows a high photocurrent density of ≈13.1 mA cm^?2, corresponding to a remarkably high solar‐to‐CO efficiency of 15.5%. Density functional theory studies suggest that the Co sites in Co₂FeO₄ are favorable to the formation of *COOH and *O intermediates and thus account for its efficient bifunctional activities. The results will facilitate future studies for designing highly effective electrocatalysts and devices for OCO₂S.     

Fine AgPd Nanoalloys Achieving Size and Ensemble Synergy for High-Efficiency CO2 to CO Electroreduction

Alloying the active metal with a second metal is an effective way to tailor the adsorption of reaction intermediates through an ensemble effect. Herein, based on theoretical calculations validating that the ensemble sites composed of Ag and Pd atoms could reduce the energy gap for *COOH and *CO intermediates generated during electrocatalytic CO₂ reduction reaction (eCO₂RR) by either weakening the CO adsorption or enhancing the COOH adsorption, a strategy to produce AgPd alloy nanoparticles with fine sizes for synergizing the ensemble effect and size leverage toward high CO faradaic efficiency in eCO₂RR is reported. In particular, the AgPd alloy nanoparticles at an optimized Ag/Pd atomic ratio of 35/65 affords a maximum CO faradaic efficiency of 98.9% and a CO partial current density of 5.1 mA cm⁻² at the potential of −0.8 V (vs RHE) with satisfactory durability of up to 25 h, outperforming those of most Pd-based electrocatalysts recently reported and demonstrating great potential for further application in producing CO via eCO₂RR at ambient conditions.     

Graphene Quantum Sheet Catalyzed Silicon Photocathode for Selective CO2 Conversion to CO

The reduction of carbon dioxide (CO₂) into chemical feedstock is drawing increasing attention as a prominent method of recycling atmospheric CO₂. Although many studies have been devoted in designing an efficient catalyst for CO₂ conversion with noble metals, low selectivity and high energy input still remain major hurdles. One possible solution is to use the combination of an earth‐abundant electrocatalyst with a photoelectrode powered by solar energy. Herein, for the first time, a p‐type silicon nanowire with nitrogen‐doped graphene quantum sheets (N‐GQSs) as heterogeneous electrocatalyst for selective CO production is demonstrated. The photoreduction of CO₂ into CO is achieved at a potential of ?1.53 V versus Ag/Ag⁺, providing 0.15 mA cm^?2 of current density, which is 130 mV higher than that of a p‐type Si nanowire decorated with well‐known Cu catalyst. The faradaic efficiency for CO is 95%, demonstrating significantly improved selectivity compared with that of bare planar Si. The density functional theory (DFT) calculations are performed, which suggest that pyridinic N acts as the active site and band alignment can be achieved for N‐GQSs larger than 3 nm. The demonstrated high efficiency of the catalytic system provides new insights for the development of nonprecious, environmentally benign CO₂ utilization.