1. Nazir, H., Louis, C., Jose, S., Prakash, J., Muthuswamy, N., Buan, M. E. M., Flox, C., Chavan, S., Shi, X., Kauranen, P., Kallio, T., Maia, G., Tammeveski, K., Lymperopoulos, N., Carcadea, E., Veziroglu, E., Iranzo, A., Kannan, A. M. Is the H2 economy realizable in the foreseeable future? Part I: H2 production methods. Int. J. Hydrogen Energy 45 (2020), 13777–13788,
https://doi.org/10.1016/j.ijhydene.2020.03.092

2. Nazir, H., Muthuswamy, N., Louis, C., Jose, S., Prakash, J., Buan, M. E. M., Flox, C., Chavan, S., Shi, X., Kauranen, P., Kallio, T., Maia, G., Tammeveski, K., Lymperopoulos, N., Carcadea, E., Veziroglu, E., Iranzo, A., Kannan, A. M. Is the H2 economy realizable in the foreseeable future? Part III: H2 usage technologies, applications, and challenges and opportunities. Int. J. Hydrogen Energy 45 (2020), 28217–28239,
https://doi.org/10.1016/j.ijhydene.2020.07.256

3. Hossen, Md. M., Hasan, Md. S., Sardar, Md. R. I., Haider, J. B., Mottakin, Tammeveski, K., Atanassov, P. State-of-the-art and developmental trends in latinum group metal-free cathode catalyst for anion exchange membrane fuel cell (AEMFC). Appl. Catal. B Environ. 325 (2023), 121733,
https://doi.org/10.1016/j.apcatb.2022.121733

4. Hyun, J., Kim, H-T. Powering the hydrogen future: current status and challenges of anion exchange membrane fuel cells. Energy Environ. Sci. 16 (2023), 5633–5662,
https://doi.org/10.1039/D3EE01768K

5. Shao, M., Chang, Q., Dodelet, J-P., Chenitz, R. Recent Advances in Electrocatalysts for Oxygen Reduction Reaction. Chem. Rev. 116 (2016), 3594–3657,
https://doi.org/10.1021/acs.chemrev.5b00462

6. Ahmed, Z., Mooste, M., Tammeveski, K. Transition metal MN4 macrocycle-derived bifunctional ORR/OER electrocatalysts for air electrodes in rechargeable zinc-air batteries. Curr. Opin. Electrochem. 55 (2026), 101783,
https://doi.org/10.1016/j.coelec.2025.101783

7. Li, J., Miao, D., Guo, X., Luo, D., Ren, J., Chen, Z. Sustainable Zinc–Air Batteries: Innovations, Challenges, and Pathways to Commercialization. Small 21 (2025), e08482,
https://doi.org/10.1002/smll.202508482

8. Kumar, Y., Mooste, M., Tammeveski, K. Recent progress of transition metal-based bifunctional electrocatalysts for rechargeable zinc–air battery application. Curr. Opin. Electrochem. 38 (2023), 101229,
https://doi.org/10.1016/j.coelec.2023.101229

9. Sarapuu, A., Lilloja, J., Akula, S., Zagal, J. H., Specchia, S., Tammeveski, K. Recent Advances in Non-Precious Metal Single-Atom Electrocatalysts for Oxygen Reduction Reaction in Low-Temperature Polymer-Electrolyte Fuel Cells. ChemCatChem 15 (2023), e202300849,
https://doi.org/10.1002/cctc.202300849

10. Sarapuu, A., Kibena-Põldsepp, E., Borghei, M., Tammeveski, K. Electrocatalysis of oxygen reduction on heteroatom-doped nanocarbons and transition metal–nitrogen–carbon catalysts for alkaline membrane fuel cells. J. Mater. Chem. A 6 (2018), 776–804,
https://doi.org/10.1039/C7TA08690C

11. Jasinski, R. A New Fuel Cell Cathode Catalyst. Nature 201 (1964), 1212–1213,
https://doi.org/10.1038/2011212a0

12. Ahmed, Z., Muñoz-Becerra, K., Akula, S., Zagal, J. H., Tammeveski, K. Recent progress on MN4 macrocycle-derived oxygen reduction reaction electrocatalysts for polymer electrolyte fuel cell applications. Chem. Commun. 62 (2026), 7680–7697,
https://doi.org/10.1039/D5CC07438J

13. Qiu, D., Wang, H., Ma, T., Huang, J., Meng, Z., Fan, D., Bowen, C. R., Lu, H., Liu, Y., Chandrasekaran, S. Promoting Electrocatalytic Oxygen Reactions Using Advanced Heterostructures for Rechargeable Zinc–Air Battery Applications. ACS Nano 18 (2024), 21651–21684,
https://doi.org/10.1021/acsnano.4c02289

14. Zhang, W., Chao, Y., Zhang, W., Zhou, J., Lv, F., Wang, K., Lin, F., Luo, H., Li, J., Tong, M., Wang, E., Guo, S. Emerging Dual-Atomic-Site Catalysts for Efficient Energy Catalysis. Adv. Mater. 33 (2021), 2102576,
https://doi.org/10.1002/adma.202102576

15. Palm, I., Kibena-Põldsepp, E., Mooste, M., Kozlova, J., Käärik, M., Kikas, A., Treshchalov, A., Leis, J., Kisand, V., Tamm, A., Holdcroft, S., Atanassov, P., Tammeveski, K. Nitrogen and Phosphorus Dual-Doped Silicon Carbide-Derived Carbon/Carbon Nanotube Composite for the Anion-Exchange Membrane Fuel Cell Cathode. ACS Appl. Energy Mater. 5 (2022), 2949–2958,
https://doi.org/10.1021/acsaem.1c03627

16. Lilloja, J., Kibena-Põldsepp, E., Sarapuu, A., Konovalova, A., Käärik, M., Kozlova, J., Paiste, P., Kikas, A., Treshchalov, A., Aruväli, J., Zitolo, A., Leis, J., Tamm, A., Kisand, V., Holdcroft, S., Tammeveski, K. Transition-Metal and Nitrogen-Doped Carbon Nanotube/Graphene Composites as Cathode Catalysts for Anion-Exchange Membrane Fuel Cells,. ACS Appl. Energy Mater. 6 (2023), 5519–5529,
https://doi.org/10.1021/acsaem.3c00613

17. Lilloja, J., Kibena-Põldsepp, E., Sarapuu, A., Käärik, M., Kozlova, J., Paiste, P., Kikas, A., Treshchalov, A., Leis, J., Tamm, A., Kisand, V., Holdcroft, S., Tammeveski, K. Transition metal and nitrogen-doped mesoporous carbons as cathode catalysts for anion-exchange membrane fuel cells. Appl. Catal. B Environ. 306 (2022), 121113,
https://doi.org/10.1016/j.apcatb.2022.121113

18. Gianola, G., Cosenza, A., Roiron, C., Pirri, C. F., Specchia, S., Atanassov, P., Zeng, J. Effect of silica leaching treatment during template-assisted synthesis on the performance of FeNC catalysts for oxygen reduction reaction. Electrochim. Acta 525 (2025), 146085,
https://doi.org/10.1016/j.electacta.2025.146085

19. Kisand, K., Sarapuu, A., Douglin, J. C., Kikas, A., Treshchalov, A., Käärik, M., Piirsoo, H.-M., Paiste, P., Aruväli, J., Leis, J., Kisand, V., Tamm, A., Dekel, D. R., Tammeveski, K. Templated Nitrogen-, Iron-, and Cobalt-Doped Mesoporous Nanocarbon Derived from an Alkylresorcinol Mixture for Anion-Exchange Membrane Fuel Cell Application. ACS Catal. 12 (2022), 14050–14061,
https://doi.org/10.1021/acscatal.2c03683

20. Sajjad, U., Sarapuu, A., Douglin, J. C., Kikas, A., Treshchalov, A., Käärik, M., Kozlova, J., Aruväli, J., Leis, J., Kisand, V., Kukli, K., Dekel, D. R., Tammeveski, K. Lignin-Derived Precious Metal-Free Electrocatalysts for Anion-Exchange Membrane Fuel Cell Application. ACS Catal. 14 (2024), 9224–9234,
https://doi.org/10.1021/acscatal.4c02136

21. Juvanen, S., Sarapuu, A., Kisand, K., Käärik, M., Kikas, A., Kozlova, J., Treshchalov, A., Aruväli, J., Leis, J., Kisand, V., Kukli, K., Tammeveski, K. Templated Rapeseed-Press-Cake-Based Materials as Efficient Oxygen Reduction Reaction Electrocatalysts. ACS Sustain. Resour. Manage. 2 (2025), 446–454,
https://doi.org/10.1021/acssusresmgt.4c00444

22. Juvanen, S., Sarapuu, A., Mooste, M., Käärik, M., Mäeorg, U., Kikas, A., Kisand, V., Kozlova, J., Treshchalov, A., Aruväli, J., Leis, J. Tamm, A., Tammeveski, K. Electroreduction of oxygen on iron- and cobalt-containing nitrogen-doped carbon catalysts prepared from the rapeseed press cake. J. Electroanal. Chem. 920 (2022), 116599,
https://doi.org/10.1016/j.jelechem.2022.116599

23. Lilloja, J., Mooste, M., Kibena-Põldsepp, E., Sarapuu, A., Kikas, A., Kisand, V., Käärik, M., Kozlova, J., Treshchalov, A., Paiste, P., Aruväli, J., Leis, J., Tamm, A., Holdcroft, S., Tammeveski, K. Cobalt-, iron- and nitrogen-containing ordered mesoporous carbon-based catalysts for anion-exchange membrane fuel cell cathode. Electrochim. Acta 439 (2023), 141676,
https://doi.org/10.1016/j.electacta.2022.141676

24. Piir, J. K., Lilloja, J., Käärik, M., Kozlova, J., Kikas, A., Treshchalov, A., Aruväli, J., Kisand, V., Leis, J., Kukli, K., Tammeveski, K. Mesoporous carbon materials doped with Co, Fe and nitrogen as oxygen reduction reaction electrocatalysts for anion-exchange membrane fuel cell. Electrochim. Acta 527 (2025), 146226,
https://doi.org/10.1016/j.electacta.2025.146226

25. Akula, S., Mooste, M., Kozlova, J., Käärik, M. Treshchalov, A., Kikas, A., Kisand, V., Aruväli, J., Paiste, P., Tamm, A., Leis, J., Tammeveski, K. Transition metal (Fe, Co, Mn, Cu) containing nitrogen-doped porous carbon as efficient oxygen reduction electrocatalysts for anion exchange membrane fuel cells. Chem. Eng. J. 458 (2023), 141468,
https://doi.org/10.1016/j.cej.2023.141468

26. Kisand, K., Sarapuu, A., Douglin, J. C., Kikas, A., Käärik, M., Kozlova, J., Aruväli, J., Treshchalov, A., Leis, J., Kisand, V., Kukli, K., Dekel, D. R., Tammeveski, K. Hierarchically Porous Fe−N−C Single-Atom Catalysts via Ionothermal Synthesis for Oxygen Reduction Reaction. ChemSusChem 18 (2025), e202401332,
https://doi.org/10.1002/cssc.202401332

27. Ibrahim, F. O., Kisand, K., Douglin, J. C., Sarapuu, A., Kikas, A., Käärik, M., Kozlova, J., Aruväli, J., Treshchalov, A., Leis, J., Kisand, V., Kukli, K., Yassin, K., Dekel, D. R., Tammeveski, K. Ionothermal synthesis of mesoporous FeNC electrocatalysts for high-performance anion-exchange membrane fuel cells. Chem. Eng. J. 510 (2025), 161560,
https://doi.org/10.1016/j.cej.2025.161560

28. Antolini, E. Palladium in fuel cell catalysis. Energy Environ. Sci. 2 (2009), 915–931,
https://doi.org/10.1039/B820837A

29. Lüsi, M., Erikson, H., Piirsoo, H-M., Paiste, P., Aruväli, J., Kikas, A., Kisand, V., Tamm, A., Tammeveski, K. Oxygen reduction reaction on PdM/C (M = Pb, Sn, Bi) alloy nanocatalysts. J. Electroanal. Chem. 917 (2022), 116391,
https://doi.org/10.1016/j.jelechem.2022.116391

30. Lüsi, M., Erikson, H., Piirsoo, H-M., Aruväli, J., Kikas, A., Kisand, V., Tamm, A., Tammeveski, K. Oxygen reduction reaction on AgPd nanocatalysts prepared by galvanic exchange. Appl. Surf. Sci. 636 (2023), 157859,
https://doi.org/10.1016/j.apsusc.2023.157859

31. Linge, J. M., Erikson, H., Kozlova, J., Kukli, K., Tammeveski, K. Oxygen reduction reaction on Ag nanocatalysts prepared by the microemulsion method. Electrochim. Acta 507 (2024), 145098,
https://doi.org/10.1016/j.electacta.2024.145098

32. Linge, J. M., Briega-Martos, V., Hutzler, A., Fritsch, B., Erikson, H., Tammeveski, K., Cherevko, S. Stability of Carbon Supported Silver Electrocatalysts for Alkaline Oxygen Reduction and Evolution Reactions. ACS Appl. Energy Mater. 6 (2023), 11497–11509,
https://doi.org/10.1021/acsaem.3c01717

33. Linge, J. M., Erikson, H., Mooste, M., Piirsoo, H-M., Kaljuvee, T., Kikas, A., Aruväli, J., Kisand, V., Tamm, A., Kannan, A. M., Tammeveski, K. Ag nanoparticles on mesoporous carbon support as cathode catalyst for anion exchange membrane fuel cell. Int. J. Hydrogen Energy 48 (2023), 11058–11070,
https://doi.org/10.1016/j.ijhydene.2022.12.138

34. Akula, S., Mooste, M., Zulevi, B., McKinney, S., Kikas, A., Piirsoo, H-M., Rähn, M., Tamm, A., Kisand, V., Serov, A., Creel, E. B., Cullen, D. A., Neyerlin, K. C., Wang, H., Odgaard, M., Reshetenko, T., Tammeveski, K. Mesoporous textured Fe-N-C electrocatalysts as highly efficient cathodes for proton exchange membrane fuel cells. J. Power Sources 520 (2022), 230819,
https://doi.org/10.1016/j.jpowsour.2021.230819

35. Shao, M., Peles, A., Shoemaker, K. Electrocatalysis on Platinum Nanoparticles: Particle Size Effect on Oxygen Reduction Reaction Activity. Nano Lett. 11 (2011), 3714–3719,
https://doi.org/10.1021/nl2017459

36. Erikson, H., Antoniassi, R. M., Solla-Gullón, J., Torresi, R. M., Tammeveski, K., Feliu, J. M. Oxygen electroreduction on small (< 10 nm) and {100}-oriented Pt nanoparticles. Electrochim. Acta 403 (2022), 139631,
https://doi.org/10.1016/j.electacta.2021.139631

37. Chambers, R., Piirsoo, H-M., Tamm, A., Kozlova, J., Kukli, K., Ritslaid, P., Treshchalov, A., Erikson, H., Tammeveski, K. Heteroatom-Doped Graphene-Supported Pt Nanoparticles as Electrocatalysts for Proton Exchange Membrane Fuel Cells. ACS Appl. Nano Mater. 7 (2024), 5943–5955,
https://doi.org/10.1021/acsanm.3c05713

38. Chambers, R., Hussain, S., Kozlova, J., Kukli, K., Ritslaid, P., Kikas, A., Kisand, V., Erikson, H., Tammeveski, K. Pt Nanoparticles Electrochemically Deposited onto Heteroatom-Doped Graphene Supports as Electrocatalysts for ORR in Acid Media. J. Electrochem. Soc. 171 (2024), 096506,
https://doi.org/10.1149/1945-7111/ad7296

39. Lilloja, J., Fetuga, O. E., Kibena-Põldsepp, E., Kikas, A., Käärik, M., Aruväli, J., Kozlova, J., Treshchalov, A., Kisand, V., Leis, J., Kukli, K., Tammeveski, K. Iron- and Nitrogen-Containing Carbon Nanotube/Carbide-Derived Carbon-Based Electrocatalysts for Oxygen Reduction Reaction in Acidic Conditions. ChemElectroChem 11 (2024), e202400341,
https://doi.org/10.1002/celc.202400341

40. Muuli, K., Mooste, M., Akula, S., Gudkova, V., Otsus, M., Kikas, A., Aruväli, J., Treshchalov, A., Kisand, V., Tamm, A., Krumme, A., Cavaliere, S., Tammeveski, K. Electrospun Carbon Nanofibre-Based Catalysts Prepared with Co and Fe Phthalocyanine for Oxygen Reduction in Acidic Medium. ChemElectroChem 10 (2023), e202300131,
https://doi.org/10.1002/celc.202300131

41. Al-Hilfi, S. H., Jiang, X., Heuer, J., Akula, S., Tammeveski, K., Hu, G., Yang, J., Wang, Hai. I., Bonn, M., Landfester, K., Müllen, K., Zhou, Y. Single-Atom Catalysts through Pressure-Controlled Metal Diffusion. J. Am. Chem. Soc. 146 (2024), 19886–19895,
https://doi.org/10.1021/jacs.4c03066

42. Akula, S., Piirsoo, H-M., Kikas, A., Kisand, V., Käärik, M., Leis, J., Treshchalov, A., Aruväli, J., Kukli, K., Tammeveski, K. ZIF-8-derived nanocarbon composite-based highly active platinum group metal-free bimetallic electrocatalysts for oxygen reduction reaction in proton exchange membrane fuel cells. Electrochim. Acta 498 (2024), 144691,
https://doi.org/10.1016/j.electacta.2024.144691

43. Kisand, K., Sarapuu, A., Akula, S., Kikas, A., Treshchalov, A., Käärik, M., Piirsoo, H-M., Kozlova, J., Aruväli, J., Leis, J., Kisand, V., Kukli, K., El Chawich, G., Jaouen, F., Cavaliere, S., Tammeveski, K. Iron and manganese co-doped mesoporous carbon-based catalysts via template-assisted synthesis for proton exchange membrane fuel cells. J. Power Sources 618 (2024), 235166,
https://doi.org/10.1016/j.jpowsour.2024.235166

44. Kumar, Y., Kibena-Põldsepp, E., Mooste, M., Kozlova, J., Kikas, A., Aruväli, J., Käärik, M., Kisand, V., Leis, J., Tamm, A., Holdcroft, S., Zagal, J. H., Tammeveski, K. Iron and Nickel Phthalocyanine-Modified Nanocarbon Materials as Cathode Catalysts for Anion-Exchange Membrane Fuel Cells and Zinc-Air Batteries. ChemElectroChem 9 (2022), e202200717,
https://doi.org/10.1002/celc.202200717

45. Muuli, K., Lyu, X., Mooste, M., Käärik, M., Zulevi, B., Leis, J., Yu, H., Cullen, D. A., Serov, A., Tammeveski, K. Outstanding platinum group metal-free bifunctional catalysts for rechargeable zinc-air batteries. Electrochim. Acta 446 (2023), 142126,
https://doi.org/10.1016/j.electacta.2023.142126

46. Mooste, M., Ahmed, Z., Kapitulskis, P., Ivanov, R., Treshchalov, A., Piirsoo, H-M., Kikas, A., Kisand, V., Kukli, K., Hussainova, I., Tammeveski, K. Bifunctional oxygen electrocatalyst based on Fe, Co, and nitrogen co-doped graphene-coated alumina nanofibers for Zn-air battery air electrode. Appl. Surf. Sci. 660 (2024), 160024,
https://doi.org/10.1016/j.apsusc.2024.160024

47. Kumar, Y., Akula, S., Kozlova, J., Kikas, A., Aruväli, J., Käärik, M., Treshchalov, A., Leis, J., Kisand, V., Kukli, K., Kibena-Põldsepp, E., Tammeveski, K. Zinc-assisted synthesis of polymer framework-based atomically dispersed bimetal catalysts for efficient oxygen electrocatalysis in rechargeable zinc-air batteries. J. Energy Storage 86 (2024), 111164,
https://doi.org/10.1016/j.est.2024.111164

48. Ahmed, Z., Kozlova, J., Kukli, K., Kikas, A., Kisand, V., Treshchalov, A., Käärik, M., Leis, J., Aruväli, J., Tammeveski, K. Boosting bifunctional oxygen electrocatalysis by integrating Fe–Nx moieties and FeNi nanoparticles for highly efficient and long-life rechargeable zinc–air batteries. Sustain. Energy Fuels 9 (2025), 2098–2108,
https://doi.org/10.1039/D5SE00072F

49. Ahmed, Z., Kozlova, J., Kikas, A., Kisand, V., Treshchalov, A., Käärik, M., Leis, J., Aruväli, J., Kukli, K., Tammeveski, K. Iron phthalocyanine assisted bifunctional oxygen electrocatalyst for high-performance and long-life rechargeable zinc–air batteries. Mater. Chem. Front. 9 (2025), 3149–3160,
https://doi.org/10.1039/D5QM00589B

50. Mooste, M., Kumar, R., Juvanen, S., Kozlova, J., Kikas, A., Treshchalov, A., Käärik, M., Aruväli, J., Leis, J., Kisand, V., Kukli, K., Schonvogel, D., Wagner, P., Wilhelm, M., Tammeveski, K., Friedrich, K. A. Binary Transition Metal and Nitrogen Functionalised Silicon Oxycarbide Electrocatalysts for Zn–Air Battery Air Electrode Application. Int. J. Energy Res. 2025 (2025), 4252866,
https://doi.org/10.1155/er/4252866

51. Zahan, S. M., Baranov, A. A., Yassin, K., Zhong, J., Douglin, J. C., Willdorf-Cohen, S., Bhowmick, S., Lilloja, J., Tammeveski, K., Tsur, Y., Dekel, D. R. Can Anion-Exchange Membrane Fuel Cells Operate with Ambient Air? ACS Energy Lett. 11 (2026), 1688–1695,
https://doi.org/10.1021/acsenergylett.5c03124