Non-precious Metal Oxygen Reduction Research Articles

Preparation of Fe-BN-C catalysts derived from ZIF-8 and their performance in the oxygen reduction reaction.

Enhancing the oxygen reduction reaction (ORR) activity and stability of the fuel cell cathode electrocatalysts and reducing their costs are critical. In response to this need, Fe, B, and N co-doped hollow mesoporous carbon materials were prepared by a simple chemical doping one-step pyrolysis method using ZIF-8 as a precursor. The results showed that the optimized catalyst displayed a higher limiting current density (6.154 mA cm-2) and half-wave potential (0.859 V), which showed significant enhancement compared with the Pt/C catalyst (5.487 mA cm-2 and 0.853 V). Moreover, the optimized catalyst had outstanding long-term stability with a current density retention higher than 91% after 36 000 s of stability testing. This work provides a facile strategy for the design of outstanding ORR performance of non-precious metal oxygen reduction catalysts.

Heat-Treatment of a Fourteen Membered Macrocyclic Fe Complex for Electrocatalytic Oxygen Reduction

For the broad application of polymer electrolyte fuel cells (PEFCs), the development of non-precious-metal (NPM) catalysts for oxygen reduction is extremely important. To date, many NPM catalyst have been synthesized by pyrolyzing Fe-, N-, and C-containing precursors, but they suffer from the low density and uncertain chemical structure of their active sites. On the contrary, our research group has been studying a fourteen-membered macrocyclic Fe complex, which was inspired by the FeNx sites embed in graphene sheets (Fig. 1).In this study, a fourteen-membered macrocyclic Fe complex was loaded on a carbon support and then heat-treated, and found to be quite active as a non-precious metal oxygen reduction catalyst. The oxygen reduction current at 0.8 V (RHE) was 13.3 A gcat -1. The improvement is attributed to a high turnover frequency rather than the number of active sites. X-ray absorption spectroscopy and temperature programmed decomposition for the Fe complex suggested that the counter anions and the protons on the nitrogen atom in the ligand were eliminated by the heat-treatment. This change probably influenced the adsorption energy of the oxygen species during the oxygen reduction and resulted in the improved catalytic activity (Fig. 2). Simulation based-on the density functional theory well support this hypothesis. Figure 1

Water hyacinth root derived hybrid metal oxides/nitrogen doped porous carbon as an efficient non-precious metal oxygen reduction reaction electrocatalyst in alkaline media

A biomass derived hybrid metal oxides/nitrogen doped porous carbon (NC) electrocatalyst is fabricated by direct pyrolysis of the water hyacinth root (WHR) mixed ZnCl2 raw materials at 600 °C (WHR600), 700 °C (WHR700) and 800 °C (WHR800) under autogenic pressure conditions. XRD analysis presents a novel Zn(Al1.8Fe0.2)O4 compound combined with hematite quart and muscovite phases for WHR700 and WHR800 samples. In addition, the WHR700 sample accounts for the maximum pyridinic N content incorporated into carbon framework (NC). Electrochemically, the WHR700 catalyst displays the highest oxygen reduction reaction (ORR) performance in alkaline media. The high ORR performance for WHR700 catalyst is significantly a result of the presence of the Zn(Al1.8Fe0.2)O4 phase and the pyridinic N species. Furthermore, an accelerate durability test for WHR700 sample over 5000 cycles exhibits only 8 mV half-wave potential reduction. The WHR700 catalyst is also extremely stable to the methanol poisoning during ORR operation.

Preparation of Fe, N co-doped oxygen reduction catalysts from sacrificial templates and their application to Zn-air batteries

Fe, N co-doped non-precious metal oxygen reduction catalysts has been prepared with nitrogen-rich precursor material (g-C3N4) as a self-sacrificing template and N source. The utilization of g-C3N4 as a nitrogen-rich material could anchor the Fe source sufficiently on its surface, and form abundant active sites. The g-C3N4-derived carbon has a high specific surface area, which facilitates the more active sites to be exposed, and the suitable pore structure provides a site for the oxygen reduction reaction. The half-wave potential of the catalyst is optimized to 0.85 V by doping with different Fe-content sources, exceeding that of commercial 20% Pt/C catalysts. The prepared catalysts also exhibit excellent electron transfer numbers along with superior methanol resistance. The prepared catalysts is loaded into Zn-Air battery devices and presenting high open-circuit voltage, power density, and specific capacitance performance. This work provides an economical and feasible preparation strategy to explore nitrogen-rich precursor materials as Fe-N-C type efficient oxygen reduction catalysts.

Se Atom Doping Enhances the Catalytic Activity of Co@NC for Oxygen Reduction Reaction

As the most promising nonprecious metal oxygen reduction reaction (ORR) catalyst, Co@NC catalysts have attracted much attention. Herein, to further improve the activity of Co@NC catalysts, Co and Se atoms are embedded in metal organic framework‐derived nitrogen‐doped porous carbon (NC) using a high‐temperature reduction strategy, and then Co–Se@NC catalysts are constructed. The ORR catalytic activity of the catalysts is evaluated by rotating disc electrodes, and the results show that the ORR catalytic activity of the Co–Se@NC catalysts is significantly enhanced compared to the Co@NC and Se@NC catalysts, demonstrating that the introduction of Se atoms into Co@NC catalysts can significantly improve the ORR catalytic activity. Spectral characterization and pore size analysis shows that the introduction of Se atoms has multiple effects, including providing new active sites, improving the pore structure of the catalyst, and promoting electron transfer and mass transport. This study shows that the Co–Se@NC catalysts has excellent catalytic performance for ORRs, reaching half‐wave potentials of 0.765 V in acidic electrolytes and 0.831 V in alkaline electrolytes, demonstrating that the introduction of Se atoms can effectively improve the ORR catalytic activity, thus providing a unique insight into the rational construction of ORR catalysts.

Increasing Accessible Active Site Density of Non-Precious Metal Oxygen Reduction Reaction Catalysts through Ionic Liquid Modification.

Non-precious metal catalysts show great promise to replace the state-of-the-art Pt-based catalysts for catalyzing the oxygen reduction reaction (ORR), while their catalytic activity still needs to be greatly improved before their broad-based application. Here, we report a facile approach to improving the performance of zeolitic imidazolate framework-derived carbon (ZDC) toward the ORR by incorporating a small amount of ionic liquid (IL). The IL would preferentially fill the micropores of ZDC and greatly enhance the utilization of the active sites within the micropores, which are initially not accessible due to insufficient surface wetting. It is also disclosed that the ORR activity in terms of kinetic current at 0.85 V depends on the loading amount of the IL, and the maximum activity is obtained at a mass ratio of IL to ZDC at 1.2. The optimum stems from the counterbalance between the enhanced utilization of the active sites within the micropores and the retarded diffusion of the reactants within the IL phase due to its high viscosity.

Co/Co2N/N/C oxygen reduction reaction catalysts derived from sisal fiber porous carbon and cobalt phthalocyanine

Sisal fibers (SF) were used as carbon source for their long and uniform multiporous structure. The composite Co/Co2N/N/C catalysts by pre-activation SF porous carbon (SPC) and cobalt phthalocyanine (CoPc) were prepared by high-temperature pyrolysis and precise control of the composite proportion of SPC and CoPc. The catalyst treated with a composite proportion of SPC and CoPc of 1 to 4 (SPC@CoPc-1-4) exhibited high Eonset potential of 1.04 V, high stability of 90.50 %, and slightly lower E1/2 of 5 mV than Pt/C (20 wt%) catalyst. Considering the performance and price of catalysts in practical application, these composite catalysts combining biomass carbon materials and phthalocyanine series will be provide a valuable reference for non-precious metal oxygen reduction reaction (ORR) catalysts.

(Keynote) Identification of Active Species and Mechanisms in Non-Precious Metal Oxygen Reduction Catalysts By Reductive Treatments and Magnetic Measurements

This talk addresses the Oxygen Reduction Reaction (ORR) utilizing Fe- and Co-based non precious metal (NPM) catalysts. There has long been uncertainty as to the active site for ORR in these materials due to the heterogeneity of the as-prepared catalyst. We report on two innovations directed at understanding the active sites in these materials. In the first, we interrogate the ORR activity in acid of a Fe porphyrin on different supports. While the activity is high when the Fe porphyrin is adsorbed on XC72 (a graphitic carbon), this activity is much lower when the porphyrin is adsorbed on either MoS2 or g-C3N4. Numerous physical characterization techniques show the electronic structure around the Fe center is the same for all three supports. Only the Fe porphyrin supported on XC72 exhibits a pH dependence in its ORR activity. This observation, coupled with the increased hydrophilicity of XC72 relative to the other supports, suggests that the support-electrolyte interaction controls the ORR activity. Modification of MoS2 to increase its hydrophilicity results in a more active ORR catalyst. In the second area, we use magnetometry and other techniques to examine the effect of two different reductive gas treatments on pyrolyzed ORR catalysts. We find that reductive gas treatments yield more superparamagnetic/ferromagnetic Fe species, with specific preparations yielding materials that consist almost entirely of reduced Fe (particularly Fe4N). Interestingly, catalysts exhibiting large percentages of superparamagnetic/ferromagnetic materials exhibit high activities for ORR catalysis as high as those reported in the literature.

Iron Single Atoms Anchored on Nitrogen-Doped Carbon Matrix/Nanotube Hybrid Supports for Excellent Oxygen Reduction Properties

Single-atom non-precious metal oxygen reduction reaction (ORR) catalysts have attracted much attention due to their low cost, high selectivity, and high activity. Herein, we successfully prepared iron single atoms anchored on nitrogen-doped carbon matrix/nanotube hybrid supports (FeSA-NC/CNTs) by the pyrolysis of Fe-doped zeolitic imidazolate frameworks. The nitrogen-doped carbon matrix/carbon nanotube hybrid supports exhibit a specific surface area of 1626.814 m2 g−1, which may facilitate electron transfer and oxygen mass transport within the catalyst and be beneficial to ORR performance. Further electrochemical results revealed that our FeSA-NC/CNTs catalyst exhibited excellent ORR activity (half-wave potential: 0.86 V; kinetic current density: 39.3 mA cm−2 at 0.8 V), superior to that of commercial Pt/C catalyst (half-wave potential: 0.846 V; kinetic current density: 14.4 mA cm−2 at 0.8 V). It also has a great stability, which makes it possible to be a valuable non-noble metal electrode material that may replace the latest commercial Pt/C catalyst in the future.

Application of rock-salt-type Co–Mn oxides for alkaline polymer electrolyte fuel cells

Co–Mn oxides are a group of highly effective non-precious metal oxygen reduction reaction (ORR) catalysts for alkaline polymer electrolyte fuel cells (APEFCs). Despite being widely studied in alkaline solutions, limited studies of them have been developed in APEFCs. In this work, we evaluate the performance of a rock-salt-type Co–Mn composite oxides (CoMnO 2 /C) in both alkaline solution and APEFCs. Other than that, we also test its durability in APEFCs and investigate its degradation mechanism. CoMnO 2 /C exhibits a high ORR activity in both rotate disk electrode (RDE) study and APEFCs test. The ORR half-wave potential is 0.86 V in 1 M KOH, and the peak power density (PPD) reaches 1.2 W/cm 2 in H 2 –O 2 APEFCs when using PtRu as anode. In air (CO 2 -free) condition, APEFC reaches a PPD of 0.83 W/cm 2 , and can operate over 40 h at a constant current density of 200 mA/cm 2 . Further experiments reveal that the cell performance degradation can be ascribed to the dissolution and valence increase of Mn from +3 to +3.6 on the catalysts surface. • CoMnO 2 /C exhibits high performance in both alkaline solution and APEFCs. • In air (CO 2 -free) condition, CoMnO 2 /C reaches a PPD of 0.83 W/cm 2 . • APEFCs using CoMnO 2 /C cathode can operate over 40 h at 200 mA/cm 2 . • Cell performance degradation is due to the dissolution and valence increase of Mn.

Deep-breathing Fe-doped superstructure modified by polyethyleneimine as oxygen reduction electrocatalysts for Zn–air batteries

The development of economical, robust and highly active non-precious metal oxygen reduction reaction (ORR) electrocatalysts to replace precious metal catalysts is crucial for the widespread applications of metal–air batteries.

A Simple Synthesis of Fe2P Nanoparticles Encapsulated Doped Carbon Nanotube as Electrocatalysts for Oxygen Reduction Reaction and Zinc‐Air Battery

The design and application of high efficiency, low cost, and nonprecious metal oxygen reduction reaction (ORR) catalyst is a prerequisite for the commercialization of energy conversion devices. Here, a simple method is proposed to prepare Fe2P nanoparticles encapsulated in nitrogen‐doped carbon nanotubes (Fe2P@NPCNTs) through a self‐growth strategy. In addition, it is worth noting that Fe2P@NPCNTs have high catalytic activity and good stability as ORR catalysts due to the unique structure of the material, the synergy between the components, and the large specific surface area. As expected, the catalyst has a half‐wave potential (0.827 V) close to commercial Pt/C and a lower Tafel slope (54.17 mV dec−1) compared to other samples. Meanwhile, the zinc‐air battery with Fe2P@NPCNTs as catalysts exhibits high open‐circuit voltage, good maximum power density, and excellent stability. Therefore, this cheap and simple method is generally available for the synthesis of other non‐noble metal catalysts for various energy systems.

Catalysts Containing Transition Metals on Nitrogen and Carbon Structures for Hydrogen Production through Salt Water Electrolysis

Hydrogen as an energy carrier is promising as it does not produce green-house gas (GHG) emissions at points of use and can be obtained from sources of low, or even neutral or negative GHG intensities [1,2]. One pathway to produce low emission hydrogen is water electrolysis when using a renewable power source [3]. However, freshwater, commonly used in this process, is relatively scarce, demand is high and expected to rise, and gets scarcer every day because of pollution [4,5,6]. An alternative is using saltwater, either through desalination or directly via adequate electrolysers [4]. Regarding direct use, a major challenge concerns catalyst, typically made of precious metals like Pt in the cathode, which are expensive, limited and susceptible to poisoning, e.g., by chlorine [7]. Likewise, in the anode chlorine is corrosive and reduces faradaic efficiency [4]. In this context, metal-coordinated nitrogen-carbon (M-N-C) nanostructures have proven to be attractive vis-à-vis these challenges [8]. To study their potential for saltwater electrolysis, five materials were synthesized following Malko et al. [8] using 1,5-diaminonaphthalene and 1% wt metallic sulphate salts of Co, Ni, Fe, Ni with Fe, and a blank without metal. The resulting material were suspended in 2-propanol and cast onto a vitreous carbon rotating ring disk electrode in both acidic solution 0,5M H2SO4 and saline medium 0,5M NaCl. Following electrode conditioning with cyclic voltammetries and electrochemical impedance characterization, linear sweep voltammetries (LSVs) were carried out in order to assess activity towards hydrogen evolution reaction (HER), coupled to hydrogen oxidation (HOR) at the Pt electrode in a ring-RDE (RRDE) fashion at constant potential of 0,3 V.The image presents HER and HOR plots in RRDE experiments at 1800 rpm, using either N-C or NiFe-N-C at a load of 0,27 mg cm-2 of catalyst at the disk and a Pt ring: (top) LSV at the disk (current normalized by geometric area, v = 2 mV/s), and (bottom) polarization at the Pt ring (E=0.3V vs NHE). Shown are both acidic medium (0.5 M H2SO4, N-C in 1 blue and NiFe-N-C in 2 red) and saline medium (0,5 M NaCl, N-C in 3 cyan and NiFe-N-C in 4 magenta). It was found that NiFe-N-C catalyst is active towards HER in saline medium at near neutral pH. As anticipated, the activity in acidic media is significantly higher than on saline medium, attributing this difference to several aspects such as conductivity limitations, chlorine presence and absence of free H+ ions and the need of additional steps for water dissociation [9]. In acidic media the metal-free catalyst (N-C) shows larger currents for most of the potential widow. On the other hand, the ring electrode does not show activity at all for N-C, thus it may be concluded that there is no H2 evolution and therefore the current is mostly capacitive, this capacitive contribution will be subtracted from the final results. In contrast, in saline medium N-C shows no activity at all towards HER, even showing smaller capacitive currents, while NiFe-C shows smaller albeit significant currents given the large differences in pH between media. The metal catalysts, the blank and a Pt/C in acidic and saline medium, will be compared using onset potentials, overpotentials at 10 mA/cm2 and Tafel slopes. References Blagojević , V. Minić, D. Minić D. & Grbović Novaković J. Hydrogen Economy: Modern Concepts, Challenges and Perspectives, Hydrogen Energy, IntechOpen (2012).Zhang,Y. & Zou, X. Noble metal-free hydrogen evolution catalysts for water splitting, Chemical Society Reviews, 15, (2015).IEA webstore, The Future of Hydrogen Seizing today´s opportunities, (2019).Dresp, S. Dionigi, F. Klingenhof, M. & Strasser, P. Direct Electrolytic Splitting of Seawater: Opportunities and Challenges, ACS Energy Letters (2019).Boretti, A. y Rosa L. Reassessing the projections of the World Water Development Report, npj Clean Water, 2, 15, (2019).Vos, J. & Koper, M. Measurement of competition between oxygen evolution and chlorine evolution using rotating ring-disk electrode voltammetry, Journal of Electroanalytical Chemistry, 819, (2018).Sethuraman, V. A. & .Weidner, J. W. Analysis of Sulfur Poisoning on a PEM Fuel Cell Electrode, Electrochimical acta, 55, 20, (2010).Malko, D. Lopes, T. Symianakis§a E. & Kucernak, A. The intriguing poison tolerance of non-precious metal oxygen reduction reaction (ORR) catalysts, Mater. Chem. A, 4, (2016).Zhou, Z. Pei, Z. Wei, L. Zhao, S. Jian, X. & Chen, Y. Electrocatalytic Hydrogen Evolution under Neutral pH Conditions: Current Understandings, Recent Advances, and Future Prospects, Energy Environ. Sci., 10, (2020) Figure 1

(Keynote) Nanostructured Materials for CO2 and Oxygen Reduction

This talk addresses the reactivity associated with CO2 and O2 reduction. For CO2, electrodeposition of metals from plating baths containing 3 an inhibitor yields highly porous materials exhibiting enhanced activity for electrochemical reactions. Electrodeposition of CuAg or CuSn alloy films from such plating baths yields high surface area catalysts for the active and selective electroreduction of CO2 to multi-carbon hydrocarbons and oxygenates. Alloy films containing Sn exhibit greater efficiency for CO production relative to either Cu along or CuAg at low overpotentials. In-situ Raman and electroanalysis studies suggest the origin of the high selectivity towards C2 products to be a combined effect of the enhanced stabilization of the Cu2O overlayer and the optimal availability of the CO intermediate due to the Ag or Sn incorporated in the alloy. Sn-containing films exhibit less Cu2O relative to either the Ag-containing or neat Cu films, likely due to the increased oxophilicity of the admixed Sn. Additionally, modification of the Cu electrode with certain polymers yields substantially enhanced reactivity, due in part to control of the Cu2O layer.For O2 reduction, we report the results of detailed magnetometry studies on non-precious metal oxygen reduction catalysts. The magnetometry clarifies uncertainties about the state of the metal in active catalysts and reports on how the catalysts change following alteration in preparation procedures, such as exposure to NH3.

Cu/Cu2O nanoparticles co-regulated carbon catalyst for alkaline Al-air batteries

Developing high-efficiency, inexpensive, and steady non-precious metal oxygen reduction reaction (ORR) catalysts to displace Pt-based catalysts is significant for commercial applications of Al-air battery. Here, we have prepared the Cu/Cu2O-NC catalyst with excellent ORR performance and high stability, due to the synergistic effect of Cu and Cu2O nanoparticles. The half-wave potential (0.8 V) and the limiting-current density (5.20 mA/cm2) of the Cu/Cu2O-NC are very close to those of the 20% Pt/C catalyst (0.82 V, 5.10 mA/cm2). Besides, it exhibits excellent performance with a maximal power density of 250 mW/cm2 and a stable continuous discharge for more than 90 h in the Al-air battery test. The promoting effects of Cu2O towards Cu-based ORR catalysts are illustrated as follows: (i) Cu2O is the major ORR active site by the redox of Cu(II)/Cu(I), which provides excellent ORR activities; (ii) Cu can stabilize the location of Cu2O by assisting the electron transfer to Cu(II)/Cu(I) redox, which is conducive to the high stability of the catalyst. This work provides a useful strategy for enhancing the ORR performance of Cu-based catalysts.

ZIF-derived Co–N–C ORR catalyst with high performance in proton exchange membrane fuel cells

Metal and nitrogen-doped carbon (M-N-C) materials have been considered as the most promising non-precious metal oxygen reduction (ORR) catalysts to replace expensive Pt catalysts. Due to high Fenton catalytic activity of Fe element and the resulting instability, Co-based N–C (Co–N–C) catalysts without Fenton catalytic activity should be a worthier ORR catalyst being explored. Although the high ORR activity of Co–N–C catalyst has been demonstrated in aqueous half-cell tests, their performance under PEMFC working condition is still far away from that of state-of-the-art Fe–N–C catalysts. In this study, a high-performance Co–N–C catalyst was synthesized by one-step pyrolyzing Co-doped ZIF-8 (zeolitic imidazolate framework-8) particles in-situ grown on the high-surface-area KJ600 carbon black with high electronic conductivity. The resulting Co–N–C catalyst exhibited high intrinsic ORR activity, fast mass transfer rate and high electronic conductivity, and thus yielded a remarkable peak power density of 0.92 W cm-2 in H2–O2 PEMFC, which is comparable to state-of-the-art Fe–N–C catalyst. This strategy is helpful to synthesize highly active M-N-C ORR catalysts with improved mass transfer and electric conductivity.

FeWO4/nitrogen-doped multi-dimensional porous carbon for the highly efficient and stable oxygen reduction reaction

Non-precious metal oxygen reduction catalysts still present considerable challenges in ensuring activity and stability in acidic/alkaline media. In this paper, the tungstate with excellent stability is selected as the electrocatalyst for oxygen reduction reaction (ORR). FeWO4/nitrogen-doped multi-dimensional porous carbon (FeWO4/N-MPC) catalyst was successfully synthesized by freeze-drying and rapid calcination methods. FeWO4/N-MPC exhibited a multi-dimensional porous carbon structure with uniformly distributing FeWO4 nanoparticles. The nitrogen-doped multi-dimensional porous carbon structure composed of nanofibers and nanosheets can significantly improve the transport efficiency of charge and O2 and effectively protect the FeWO4 nanoparticles, further leading to enhance catalytic activity and stability of FeWO4/N-MPC. Thus, FeWO4/N-MPC exhibited excellent catalytic performance for ORR in acidic/alkaline media. The long-term durability of FeWO4/N-MPC was also remarkably more outstanding than that of 20 wt% Pt/C catalyst in acidic/alkaline media. The long-term durability of FeWO4/N-MPC had also made it possible to apply in metal-air batteries and fuel cells.

Identification of Active Species and Mechanisms in Non-Precious Metal Oxygen Reduction Catalysts By Poisoning and Magnetic Measurements

This talk addresses the Oxygen Reduction Reaction (ORR) utilizing Fe- and Co-based non precious metal (NPM) catalysts. There has long been uncertainty as to the active site for ORR in these materials due to the heterogeneity of the as-prepared catalyst. We have developed several methods with which to interrogate these materials. First, by using a purification scheme which removes and then remetallates the active site we substantially reduce catalyst heterogeneity. Second, we have developed a method by which to poison some of these active sites. Third, we use magnetic measurements to probe those sites affected by poisoning. We show as well that there is a minimum metal requirement for high ORR activity and that the metal must be arranged in certain critical configurations.

Ordered mesoporous carbon assisted Fe–N–C for efficient oxygen reduction catalysis in both acidic and alkaline media

Fe–N–C catalyst obtained by high temperature pyrolysis is one of the most promising electrocatalysts for non-precious metal oxygen reduction reaction (ORR). However, up to now, the lesser density of active sites results in a substantial performance gap between the Fe–N–C materials and the conventional Pt/C ORR catalysts. Herein, an N-doped mesoporous carbon is employed as the support for the dispersion of poly-m-phenylenediamine. With high specific surface areas of 1526 m2 g−1, the as-prepared Fe–N–C materials show the half-wave potential of 0.89 V and 0.79 V in 0.1 M KOH and 0.5 M H2SO4, respectively. Notably, the superior methanol tolerance, as well as excellent stability, makes our Fe–N–C materials as competitive candidates for oxygen electrochemical catalysis.

Molecular-Scale Mechanistic Investigation of Oxygen Dissociation and Adsorption on Metal Surface-Supported Cobalt Phthalocyanine.

Ultrahigh vacuum scanning tunneling microscopy and density functional theory are used to investigate adsorption of oxygen on cobalt phthalocyanine (CoPc), a promising nonprecious metal oxygen reduction catalyst, supported on Ag(111), Cu(111), and Au(111) surfaces at the molecular scale. Four distinct molecular and atomic oxygen adsorption configurations are observed for CoPc supported on Ag(111) surfaces, which are assigned as O2/CoPc/Ag(111), O/CoPc/Ag(111), CoPc/(O)2/Ag(111), and (O)2/CoPc/Ag(111). In contrast, no oxygen adsorption is observed for CoPc supported on Cu(111) and Au(111) surfaces. The results show that for Ag(111), atomic O that is predominantly catalytically produced from the dissociation of molecular O2 at metal surface step edges is responsible for the observed adsorption configurations. However, Cu(111) binds atomic O too strongly, and Au(111) does not produce atomic O. These results show the active role of the supporting metal surface in facilitating oxygen adsorption on CoPc.