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The nitrate (NO3−) electroreduction into ammonia (NH3) represents a promising approach for sustainable NH3 synthesis. However, the variation of adsorption configurations renders great difficulties in the simultaneous optimization of binding energy for the intermediates. Though the extensively reported Cu-based electrocatalysts benefit NO3− adsorption, one of the key issues lies in the accumulation of nitrite (NO2−) due to its weak adsorption, resulting in the rapid deactivation of catalysts and sluggish kinetics of subsequent hydrogenation steps. Here we report a tandem electrocatalyst by combining Cu single atoms catalysts with adjacent Co3O4 nanosheets to boost the electroreduction of NO3− to NH3. The obtained tandem catalyst exhibits a yield rate for NH3 of 114.0 mg NH 3 h−1 cm−2, which exceeds the previous values for the reported Cu-based catalysts. Mechanism investigations unveil that the combination of Co3O4 regulates the adsorption configuration of NO2− and strengthens the binding with NO2−, thus accelerating the electroreduction of NO3− to NH3. An optimal catalyst for nitrate electroreduction should satisfy the simultaneously optimized adsorption of intermediates. Here, the authors report a tandem electrocatalyst by combining Cu single atoms with Co3O4 nanosheets, enhancing the binding with NO2−, thus promoting nitrate electroreduction to NH3. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction (CO2ER) to valuable chemicals, for example, HCOOH have received widespread attention, which still suffers from moderate Faradaic efficiency with low current regarding the wide industrial application of HCOOH. Herein, we employed a strategy of modifying electronic metal‐support interaction (EMSI) by fabricating Bi nanoparticles supported Ni‐modified Bi2O2CO3 (Bi/Ni‐BOC) heterostructure. The obtained Bi/Ni‐BOC exhibited high formate Faradic efficiency (FEHCOOH) of 97% at −2.1 V (vs. Ag/AgCl) and above 90% within broad potential range (−1.7 to −2.2 V) in flow cell with superior stability at high current density of ~220 mA cm−2, and formate concentration can reach 2.4 mmol h−1 cm−2 at −2.3 V. In/ex situ x‐ray absorption fine structure (XAFS) and density functional theory (DFT) calculation indicated that Ni doping promoted the enhancement of EMSI, which improved the generation and stable existence of electron‐rich Bi to boost CO2 activation and *OHCO hydrogenation, thus facilitating highly‐efficient formate production with hydrogen evolution reaction (HER) inhibition. [ABSTRACT FROM AUTHOR]

Amorphous nano-metal catalysts often exhibit appealing catalytic properties, because the intrinsic linear scaling relationship can be broken. However, accurate control synthesis of amorphous nano-metal catalysts with desired size and morphology is a challenge. In this work, we discover that Cu(0) could be oxidized to amorphous CuxO species by supercritical CO2. The formation process of the amorphous CuxO is elucidated with the aid of machine learning. Based on this finding, a method to prepare Cu nanoparticles with an amorphous shell is proposed by supercritical CO2 treatment followed by electroreduction. The unique feature of this method is that the size of the particles with amorphous shell can be easily controlled because their size depends on that of the original crystal Cu nanoparticles. Moreover, the thickness of the amorphous shell can be easily controlled by CO2 pressure and/or treatment time. The obtained amorphous Cu shell exhibits high selectivity for C2+ products with the Faradaic efficiency of 84% and current density of 320 mA cm−2. Especially, the FE of C2+ oxygenates can reach up to 65.3 %, which is different obviously from the crystalline Cu catalysts. Amorphous metal catalysts often exhibit appealing catalytic properties, however, accurate control synthesis of amorphous nano-metal catalysts is a challenge. Here, the authors report a feasible strategy to prepare the amorphous Cu catalysts by supercritical CO2 treatment followed by electroreduction. The resulted catalyst shows high selectivity towards multi-carbon products for CO2 electroreduction. [ABSTRACT FROM AUTHOR]

Regulating the coordination environment via heteroatoms to break the symmetrical electronic structure of M‐N4 active sites provides a promising route to engineer metal‐nitrogen‐carbon catalysts for electrochemical CO2 reduction reaction. However, it remains challenging to realize a site‐specific introduction of heteroatoms at atomic level due to their energetically unstable nature. Here, this paper reports a facile route via using an oxygen‐ and nitrogen‐rich metal–organic framework (MOF) (IRMOF‐3) as the precursor to construct the Fe‐O and Fe‐N chelation, simultaneously, resulting in an atomically dispersed axial O‐coordinated FeN4 active site. Compared to the FeN4 active sites without O coordination, the formed FeN4‐O sites exhibit much better catalytic performance toward CO, reaching a maximum FECO of 95% at −0.50 V versus reversible hydrogen electrode. To the best of the authors' knowledge, such performance exceeds that of the existing Fe‐N‐C‐based catalysts derived from sole N‐rich MOFs. Density functional theory calculations indicate that the axial O‐coordination regulates the binding energy of intermediates in the reaction pathways, resulting in a smoother desorption of CO and increased energy for the competitive hydrogen production. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of CO2 to valuable fuels is appealing for CO2 fixation and energy storage. The Cu‐based catalysts feature unique superiorities, but achieving high ethylene selectivity is still restricted. In this study, we propose the anchoring of an ionic liquid (IL) on a Cu electrocatalyst for improving the electrochemical CO2 reduction to ethylene. In a water‐based electrolyte and a commonly used H‐type cell, a high ethylene Faradaic efficiency of 77.3 % was achieved at −1.49 V (vs. RHE). Experimental and theoretical studies reveal that an IL can modify the electronic structure of a Cu catalyst through its interaction with Cu, making it more conducive to *CO dimerization for ethylene formation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Using renewable electricity to drive CO2 electroreduction is an attractive way to achieve carbon‐neutral energy cycle and produce value‐added chemicals and fuels. As an important platform molecule and clean fuel, methanol requires 6‐electron transfer in the process of CO2 reduction. Currently, CO2 electroreduction to methanol suffers from poor efficiency and low selectivity. Herein, we report the first work to design atomically dispersed Sn site anchored on defective CuO catalysts for CO2 electroreduction to methanol. It exhibits high methanol Faradaic efficiency (FE) of 88.6 % with a current density of 67.0 mA cm−2 and remarkable stability in a H‐cell, which is the highest FE(methanol) with such high current density compared with the results reported to date. The atomic Sn site, adjacent oxygen vacancy and CuO support cooperate very well, leading to higher double‐layer capacitance, larger CO2 adsorption capacity and lower interfacial charge transfer resistance. Operando experiments and density functional theory calculations demonstrate that the catalyst is beneficial for CO2 activation via decreasing the energy barrier of *COOH dissociation to form *CO. The obtained key intermediate *CO is then bound to the Cu species for further reduction, leading to high selectivity toward methanol. [ABSTRACT FROM AUTHOR]

A Cu–N-doped carbon nanotube with an unsaturated coordination Cu atom (Cu–N3) was fabricated and it exhibited over 90% CO faradaic efficiency (FE) in a wide potential range from −0.42 to −0.92 V. The maximum CO FE can reach 98.7% with a high CO partial current density of 234.3 mA cm−2 in a flow cell. Theoretical calculations elucidated that the Cu–N3 site facilitated the formation of COOH*, thereby accelerating the CO2 electrochemical reduction. [ABSTRACT FROM AUTHOR]

Fundamental understanding of the dependence between the structure and composition on the electrochemical CO2 reduction reaction (CO2RR) would guide the rational design of highly efficient and selective electrocatalysts. A major impediment to the deep reduction CO2 to multi‐carbon products is the complexity of carbon–carbon bond coupling. The chemically well‐defined catalysts with atomically dispersed dual‐metal sites are required for these C−C coupling involved processes. Here, we developed a catalyst (BIF‐102NSs) that features Cl− bridged dimer copper (Cu2) units, which delivers high catalytic activity and selectivity for C2H4. Mechanistic investigation verifies that neighboring Cu monomers not only perform as regulator for varying the reaction barrier, but also afford distinct reaction paths compared with isolated monomers, resulting in greatly improved electroreduction performance for CO2. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 to liquid fuels such as ethanol and n‐propanol, powered by renewable electricity, offers a promising strategy for controlling the global carbon balance and addressing the need for the storage of intermittent renewable energy. In this work, we discovered that the composite composed of nitrogen‐doped graphene quantum dots (NGQ) on CuO‐derived Cu nanorods (NGQ/Cu‐nr) was an outstanding electrocatalyst for the reduction of CO2 to ethanol and n‐propanol. The Faradaic efficiency (FE) of C2+ alcohols could reach 52.4 % with a total current density of 282.1 mA cm−2. This is the highest FE for C2+ alcohols with a commercial current density to date. Control experiments and DFT studies show that the NGQ/Cu‐nr could provide dual catalytic active sites and could stabilize the CH2CHO intermediate to enhance the FE of alcohols significantly through further carbon protonation. The NGQ and Cu‐nr had excellent synergistic effects for accelerating the reduction of CO2 to alcohols. [ABSTRACT FROM AUTHOR]

Novel boron-doped CuO nanobundles are designed for CO2 reduction to the single multi-carbon product of ethylene, and their faradaic efficiency can reach 58.4% with a current density of 18.2 mA cm−2. This active, selective and simply prepared electrocatalyst provides a promising electrocatalyst candidate for CO2 reduction to ethylene. [ABSTRACT FROM AUTHOR]

The general synthesis and control of the coordination environment of single‐atom catalysts (SACs) remains a great challenge. Herein, a general host–guest cooperative protection strategy has been developed to construct SACs by introducing polypyrrole (PPy) into a bimetallic metal–organic framework. As an example, the introduction of Mg2+ in MgNi‐MOF‐74 extends the distance between adjacent Ni atoms; the PPy guests serve as N source to stabilize the isolated Ni atoms during pyrolysis. As a result, a series of single‐atom Ni catalysts (named NiSA‐Nx‐C) with different N coordination numbers have been fabricated by controlling the pyrolysis temperature. Significantly, the NiSA‐N2‐C catalyst, with the lowest N coordination number, achieves high CO Faradaic efficiency (98 %) and turnover frequency (1622 h−1), far superior to those of NiSA‐N3‐C and NiSA‐N4‐C, in electrocatalytic CO2 reduction. Theoretical calculations reveal that the low N coordination number of single‐atom Ni sites in NiSA‐N2‐C is favorable to the formation of COOH* intermediate and thus accounts for its superior activity. [ABSTRACT FROM AUTHOR]

To develop novel strategies for fabricating metal carbon‐based materials with desirable compositions and structures for catalysis is of great importance. Here we propose for the first time the utilization of metal ionic liquid as a precursor for the synthesis of metal carbon‐based materials through a one‐step pyrolysis route. The method produces the metal dispersed cross‐linked carbon framework with a highly mesoporous structure. Such a Ni/C−N catalyst exhibits outstanding electrocatalytic activity for CO2 reduction reaction, i. e., an excellent CO faradaic efficiency of approximately 94 % at an potential of −0.75 V (versus the reversible hydrogen electrode). The method proposed in this work is simple, convenient, low‐cost, adjustable and versatile for the synthesis of different kinds of M/C−N materials because the structures and properties of metal ionic liquids can be easily designed and tuned by changing the anions and cations. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO2 into energy‐dense chemical feedstock and fuels provides an attractive pathway to sustainable energy storage and artificial carbon cycle. Herein, we report the first work to use atomic Ir electrocatalyst for CO2 reduction. By using α‐Co(OH)2 as the support, the faradaic efficiency of CO could reach 97.6 % with a turnover frequency (TOF) of 38290 h−1 in aqueous electrolyte, which is the highest TOF up to date. The electrochemical active area is 23.4‐times higher than Ir nanoparticles (2 nm), which is highly conductive and favors electron transfer from CO2 to its radical anion (CO2.−). Moreover, the more efficient stabilization of CO2.− intermediate and easy charge transfer makes the atomic Ir electrocatalyst facilitate CO production. Hence, α‐Co(OH)2‐supported atomic Ir electrocatalysts show enhanced CO2 activity and stability. High‐density atomic Ir supported on α‐Co(OH)2 had outstanding performance for CO2 reduction to CO. The faradaic efficiency can reach 97.6 % with a TOF of 38 290 h−1. The high catalytic activity is attributed to more active sites for CO2 adsorption and activation and the higher efficiency in stabilizing the CO2.− intermediate. [ABSTRACT FROM AUTHOR]

Developing effective catalysts based on earth abundant elements is critical for CO2 electroreduction. However, simultaneously achieving a high Faradaic efficiency (FE) and high current density of CO (jCO) remains a challenge. Herein, we prepare a Mn single-atom catalyst (SAC) with a Mn-N3 site embedded in graphitic carbon nitride. The prepared catalyst exhibits a 98.8% CO FE with a jCO of 14.0 mA cm−2 at a low overpotential of 0.44 V in aqueous electrolyte, outperforming all reported Mn SACs. Moreover, a higher jCO of 29.7 mA cm−2 is obtained in an ionic liquid electrolyte at 0.62 V overpotential. In situ X-ray absorption spectra and density functional theory calculations demonstrate that the remarkable performance of the catalyst is attributed to the Mn-N3 site, which facilitates the formation of the key intermediate COOH* through a lowered free energy barrier. Developing effective catalysts based on earth abundant elements is critical for electrochemical CO2 reduction. Here, the authors prepare a manganese single atom catalyst with high CO2 reduction performance, which can be attributed to the Mn-N3 site embedded in graphitic carbon nitride. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Efficient electroreduction of carbon dioxide to multicarbon products in aqueous solution is of great importance and challenging. Unfortunately, the low efficiency of the production of C2 products limits implementation at scale. Here, we report reduction of carbon dioxide to C2 products (acetic acid and ethanol) over a 3D dendritic copper-cuprous oxide composite fabricated by in situ reduction of an electrodeposited copper complex. In potassium chloride aqueous electrolyte, the applied potential was as low as −0.4 V vs reversible hydrogen electrode, the overpotential is only 0.53 V (for acetic acid) and 0.48 V (for ethanol) with high C2 Faradaic efficiency of 80% and a current density of 11.5 mA cm−2. The outstanding performance of the electrode for producing the C2 products results mainly from near zero contacting resistance between the electrocatalysts and copper substrate, abundant exposed active sites in the 3D dendritic structure and suitable copper(I)/copper(0) ratio of the electrocatalysts. Electrocatalytic reduction of carbon dioxide is attractive for obtaining multicarbon products, but conversion efficiency is low. Here the authors use copper complex materials for electrochemical reduction of carbon dioxide to ethanol and acetic acid with high efficiencies and activities. [ABSTRACT FROM AUTHOR]

Single-atom catalysts (SACs) have emerged as one of the most competitive catalysts toward a variety of important electrochemical reactions, thanks to their maximum atom economy, unique electronic and geometric structures. However, the role of SACs supports on the catalytic performance does not receive enough research attentions. Here, we report an efficient route for synthesis of single atom Zn loading on the N-doped carbon nano-onions (ZnN/CNO). ZnN/CNO catalysts show an excellent high selectivity for CO 2 electro-reduction to CO with a Faradaic efficiency of CO (FE CO) up to 97% at −0.47 V (vs. reversible hydrogen electrode, RHE) and remarkable durability without activity decay. To our knowledge, ZnN/CNO is the best activity for the Zn based catalysts up to now, and superior to single atom Zn loading on the two-dimensional planar and porous structure of graphene substrate, although the graphene with larger surface area. The exact role of such carbon nano-onions (CNO) support is studied systematically by coupling characterizations and electrochemistry with density functional theory (DFT) calculations, which have attributed such good performance to the increased curvature. Such increased curvature modifies the surface charge, which then changes the adsorption energies of key intermediates, and improves the selectivity for CO generation accordingly. [ABSTRACT FROM AUTHOR]

Electrochemical production of hydrogen peroxide (H 2 O 2) is a sustainable and environmentally benign process. The electrochemical oxygen reduction process (ORR) via a two electron pathway (2e- ORR) offers a practical method for on-site H 2 O 2 generation. As an earth-abundant catalyst, the cobalt-nitrogen coordinated systems integrated into the carbon matrix (Co-NC) has caused wide attention for its high activity in 2e- ORR. Even though most of the reported Co-NC catalysts have classical planar Co-N 4 coordination, axial coordination engineering has recently emerged as an effective way to control the active sites in the axial direction by using different coordination ligands. The structure-function link between the Co-N configuration of non-planar coordination and 2e- ORR activity is, however, not fully understood. An axial-N coordinated Co-N 5 motif embedded in hierarchically porous graphite-3R carbon (Co-N 5 C) was effectively synthesized using a template-sacrificing method. The Co-N 5 C has a high selectivity for 2e- ORR and a high H 2 O 2 molar production rate of up to 6.78 mol peroxide/g catalyst /h in acidic media, both of which are better than its Co-N 4 counterpart. DFT analyses demonstrate that axial-N ligands regulated the d -band center of the Co atom in the Co-N 5 C catalyst, inducing a shift in Δ G *OOH near the Sabatier volcano plot's peak (Δ G *OOH = 4.22 eV). This optimized the binding of the *OOH intermediate and then enhanced the protonation of *OOH to produce H 2 O 2 more efficiently. [Display omitted] • A Co-N 5 C catalyst containing an axial-N ligand was synthesized for the effective ORR. • Co-N 5 C, with graphite-3R phase, showed a specific BET surface area of 801.6 m2/g. • Co-N 5 C exhibited a high selectivity for 2e- ORR and H 2 O 2 molar production rate. • Co-N 5 C possessed a high active SD and high intrinsic kinetic TOF. [ABSTRACT FROM AUTHOR]

• Electrochemical reduction was employed to improve Cr(VI) removal by magnetite. • Cr(VI) was reduced to Cr(III) and subsequently precipitated on magnetite in KNO 3. • The highest Cr removal capacity of magnetite reached as high as 514.7 mg g−1. • Relatively low pH and applied potential facilitated Cr(VI) removal. • Cr(VI) was completely reduced in K 2 SO 4 electrolyte without Cr(OH) 3 formation. Aqueous hexavalent chromium (Cr(VI)) poses serious threats to ecological environments. Magnetite is a potential adsorbent for Cr(VI). However, its adsorption capacity is limited due to the formation of Fe(III) oxide coating on magnetite surface. Herein, constant potential reduction was conducted to improve the Cr(VI) removal capacity of magnetite, and the influence of pH, potential, and supporting electrolytes including KNO 3 , KCl, and K 2 SO 4 on the adsorption capacity was also investigated. The results showed that the highest Cr(VI) reduction percentage reached 93.7% with a total Cr removal capacity of 514.7 mg g−1 at optimized pH 2 and −0.2 V (vs. SCE) in supporting electrolyte of KNO 3. Cr(VI) was reduced to Cr(III) on the surface of magnetite due to the direct electrochemical reduction at low potentials and reduction by Fe2+ aq electrochemically generated from magnetite. The Cr(III) was subsequently removed and easily separated due to the formation of Cr(OH) 3 precipitate on magnetite surface when KNO 3 and KCl were used as supporting electrolyte; however, when K 2 SO 4 was used instead, Cr(OH) 3 precipitate was not observed. The decrease in pH and electrical potential was found to facilitate the reduction and removal of Cr(VI). This work proposes a facile method to enhance Cr(VI) removal by iron oxides. [ABSTRACT FROM AUTHOR]

Multi-walled carbon nanotubes (MWCNTs) supported iron phthalocyanine (FePc), binuclear iron phthalocyanine (bi-FePc) and iron polyphthalocyanine (FePPc) were prepared by a solvothermal process. The resulting FePc/MWCNTs, bi-FePc/MWCNTs and FePPc/MWCNTs were heat-treated in argon (Ar) atmosphere at various temperatures ranging from 500 to 900 °C to obtain optimized catalysts for the oxygen reduction reaction (ORR). The crystal structure, morphology and chemical environment of the catalysts were examined by ultraviolet-visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure spectroscopy (XAFS). The electrocatalytic activity of the obtained catalysts was measured using a rotating disk electrode (RDE) technique in 0.5 mol L −1 H 2 SO 4 solution saturated with oxygen. The ORR activity of the heat-treated FePPc/MWCNTs was found to be better than that of the heat-treated bi-FePc/MWCNTs and FePc/MWCNTs. Furthermore, the heat-treatment temperature greatly influenced the catalytic ORR ability of the catalysts. The FePPc/MWCNTs heat-treated at 800 °C exhibited a four-electron transfer process and the best ORR activity (E ORR = 0.79 V vs. RHE), methanol resistance, and stability (current loss = 13% at –0.13 V vs. Hg/Hg 2 SO 4 after 55 h). XPS indicated that pyridine-type nitrogen, not graphitic-N, played a critical role in determining the electrocatalytic ORR activity of the amples. XAFS showed that the coordination geometry around Fe was close to square planar in structure, suggesting that the Fe-N 4 structure was produced by the high temperature treatment. [ABSTRACT FROM AUTHOR]

• A hierarchically Fe, N CO doped porous carbon material is synthesized as robust catalyst for CO 2 electroreduction. • The Faradaic efficiency of CO reaches 96 % with an ultra-low overpotential of 470 mV and excellent durability. • The Fe-N 4 O stucture was found having a better catalytic performance than Fe-N 4 for CO 2 electroreduction to CO. Electrochemical reduction of carbon dioxide (CO 2) is a potentially useful step in energy storage and greenhouse gas alleviation. Here we demonstrate for the first time a Fe-N 4 O-doped nanoporous carbon as robust electrocatalyst for CO 2 reduction, where the five-coordinated Fe-N 4 O structure works as catalytically active site. It exhibits a high faradaic efficiency of 96 % towards CO with partial current density of -5.4 mA cm−2 at low overpotential of 470 mV. First-principles density functional theory calculations reveal that the free energy barrier for *CO desorption is greatly reduced on Fe-N 4 O site compared to Fe-N 4 , resulting in a higher selectivity to CO for a wider electrochemical window. This work opens up new possibilities for improving the catalytic performance of metal-N-C electrocatalysts by regulating the co-ordination of metal atom. [ABSTRACT FROM AUTHOR]