Molecularly engineered photocatalyst sheet for scalable solar formate production from carbon dioxide and water


Harvesting solar energy to convert CO2 into chemical fuels is a promising technology to curtail the growing atmospheric CO2 levels and alleviate the global dependence on fossil fuels; however, the assembly of efficient and robust systems for the selective photoconversion of CO2 without sacrificial reagents and external bias remains a challenge. Here we present a photocatalyst sheet that converts CO2 and H2O into formate and O2 as a potentially scalable technology for CO2 utilization. This technology integrates lanthanum- and rhodium-doped SrTiO3 (SrTiO3:La,Rh) and molybdenum-doped BiVO4 (BiVO4:Mo) light absorbers modified by phosphonated Co(ii) bis(terpyridine) and RuO2 catalysts onto a gold layer. The monolithic device provides a solar-to-formate conversion efficiency of 0.08 ± 0.01% with a selectivity for formate of 97 ± 3%. As the device operates wirelessly and uses water as an electron donor, it offers a versatile strategy toward scalable and sustainable CO2 reduction using molecular-based hybrid photocatalysts.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: CotpyP-loaded SrTiO3:La,Rh|Au|RuO2-BiVO4:Mo photocatalyst sheet.
Fig. 2: Photosynthetic activity of the CotpyP-loaded SrTiO3:La,Rh|Au|RuO2-BiVO4:Mo sheet for CO2RR coupled to water oxidation under AM 1.5 G irradiation.
Fig. 3: CotpyP-loaded SrTiO3:La,Rh|Au|RuO2-BiVO4:Mo photocatalyst sheet with an active irradiated area of ~20 cm2 for photosynthetic CO2RR coupled with water oxidation.
Fig. 4: Selectivity and stability of the CotpyP-loaded SrTiO3:La,Rh|Au|RuO2-BiVO4:Mo sheet for CO2RR coupled with water oxidation.
Fig. 5: O2-tolerance of CotpyP catalyst.

Data availability

The data supporting the findings of the study are available in the paper and its supplementary materials. Source data for the main figures (Figs. 25) are provided with the paper. Other source data supporting the findings of this study are available from the Cambridge data repository (


  1. 1.

    Costentin, C., Robert, M. & Savéant, J.-M. Catalysis of the electrochemical reduction of carbon dioxide. Chem. Soc. Rev. 42, 2423–2436 (2013).

    Google Scholar 

  2. 2.

    Francke, R., Schille, B. & Roemelt, M. Homogeneously catalyzed electroreduction of carbon dioxide—methods, mechanisms, and catalysts. Chem. Rev. 118, 4631–4701 (2018).

    Google Scholar 

  3. 3.

    Sato, S., Morikawa, T., Saeki, S., Kajino, T. & Motohiro, T. Visible-light-induced selective CO2 reduction utilizing a ruthenium complex electrocatalyst linked to a p-type nitrogen-doped Ta2O5 semiconductor. Angew. Chem. Int. Ed. 49, 5101–5105 (2010).

    Google Scholar 

  4. 4.

    Wang, W.-H., Himeda, Y., Muckerman, J. T., Manbeck, G. F. & Fujita, E. CO2 hydrogenation to formate and methanol as an alternative to photo- and electrochemical CO2 reduction. Chem. Rev. 115, 12936–12973 (2015).

    Google Scholar 

  5. 5.

    Kuriki, R. et al. Nature-inspired, highly durable CO2 reduction system consisting of a binuclear ruthenium(ii) complex and an organic semiconductor using visible light. J. Am. Chem. Soc. 138, 5159–5170 (2016).

    Google Scholar 

  6. 6.

    Liu, X., Inagaki, S. & Gong, J. Heterogeneous molecular systems for photocatalytic CO2 reduction with water oxidation. Angew. Chem. Int. Ed. 55, 14924–14950 (2016).

    Google Scholar 

  7. 7.

    Kuriki, R. et al. Robust binding between carbon nitride nanosheets and a binuclear ruthenium(ii) complex enabling durable, selective CO2 reduction under visible light in aqueous solution. Angew. Chem. Int. Ed. 56, 4867–4871 (2017).

    Google Scholar 

  8. 8.

    Dalle, K. E. et al. Electro- and solar-driven fuel synthesis with first row transition metal complexes. Chem. Rev. 119, 2752–2875 (2019).

    Google Scholar 

  9. 9.

    Tu, W., Zhou, Y. & Zou, Z. Photocatalytic conversion of CO2 into renewable hydrocarbon fuels: state-of-the-art accomplishment, challenges, and prospects. Adv. Mater. 26, 4607–4626 (2014).

    Google Scholar 

  10. 10.

    Sato, S. et al. Selective CO2 conversion to formate conjugated with H2O oxidation utilizing semiconductor/complex hybrid photocatalysts. J. Am. Chem. Soc. 133, 15240–15243 (2011).

    Google Scholar 

  11. 11.

    Arai, T., Sato, S., Kajino, T. & Morikawa, T. Solar CO2 reduction using H2O by a semiconductor/metal-complex hybrid photocatalyst: enhanced efficiency and demonstration of a wireless system using SrTiO3 photoanodes. Energy Environ. Sci. 6, 1274–1282 (2013).

    Google Scholar 

  12. 12.

    Sahara, G. et al. Photoelectrochemical reduction of CO2 coupled to water oxidation using a photocathode with a Ru(ii)–Re(i) complex photocatalyst and a CoOx/TaON photoanode. J. Am. Chem. Soc. 138, 14152–14158 (2016).

    Google Scholar 

  13. 13.

    Kumagai, H. et al. Hybrid photocathode consisting of a CuGaO2 p-type semiconductor and a Ru(ii)–Re(i) supramolecular photocatalyst: Non-biased visible-light-driven CO2 reduction with water oxidation. Chem. Sci. 8, 4242–4249 (2017).

    Google Scholar 

  14. 14.

    Nakada, A. et al. Solar water oxidation by a visible-light-responsive tantalum/nitrogen-codoped rutile titania anode for photoelectrochemical water splitting and carbon dioxide fixation. ChemPhotoChem 3, 37–45 (2019).

    Google Scholar 

  15. 15.

    Wang, Q. et al. Particulate photocatalyst sheets based on carbon conductor layer for efficient Z-scheme pure-water splitting at ambient pressure. J. Am. Chem. Soc. 139, 1675–1683 (2017).

    Google Scholar 

  16. 16.

    Pinaud, B. A. et al. Technical and economic feasibility of centralized facilities for solar hydrogen production via photocatalysis and photoelectrochemistry. Energy Environ. Sci. 6, 1983–2002 (2013).

    Google Scholar 

  17. 17.

    Lian, S., Kodaimati, M. S., Dolzhnikov, D. S., Calzada, R. & Weiss, E. A. Powering a CO2 reduction catalyst with visible light through multiple sub-picosecond electron transfers from a quantum dot. J. Am. Chem. Soc. 139, 8931–8938 (2017).

    Google Scholar 

  18. 18.

    Rao, H., Schmidt, L. C., Bonin, J. & Robert, M. Visible-light-driven methane formation from CO2 with a molecular iron catalyst. Nature 548, 74–77 (2017).

    Google Scholar 

  19. 19.

    Cometto, C. et al. A carbon nitride/Fe quaterpyridine catalytic system for photostimulated CO2-to-CO conversion with visible light. J. Am. Chem. Soc. 140, 7437–7440 (2018).

    Google Scholar 

  20. 20.

    Li, P. et al. All-solid-state Z-scheme system arrays of Fe2V4O13/RGO/CdS for visible light-driving photocatalytic CO2 reduction into renewable hydrocarbon fuel. Chem. Commun. 51, 800–803 (2015).

    Google Scholar 

  21. 21.

    Iwase, A. et al. Water splitting and CO2 reduction under visible light irradiation using Z-scheme systems consisting of metal sulfides, CoOx-loaded BiVO4, and a reduced graphene oxide electron mediator. J. Am. Chem. Soc. 138, 10260–10264 (2016).

    Google Scholar 

  22. 22.

    Suzuki, T. M. et al. Z-schematic and visible-light-driven CO2 reduction using H2O as an electron donor by a particulate mixture of a Ru-complex/(CuGa)1−xZn2xS2 hybrid catalyst, BiVO4 and an electron mediator. Chem. Commun. 54, 10199–10202 (2018).

    Google Scholar 

  23. 23.

    Li, X., Yu, J., Jaroniec, M. & Chen, X. Cocatalysts for selective photoreduction of CO2 into solar fuels. Chem. Rev. 119, 3962–4179 (2019).

    Google Scholar 

  24. 24.

    Wang, Q. et al. Scalable water splitting on particulate photocatalyst sheets with a solar-to-hydrogen energy conversion efficiency exceeding 1%. Nat. Mater. 15, 611–615 (2016).

    Google Scholar 

  25. 25.

    Minegishi, T., Nishimura, N., Kubota, J. & Domen, K. Photoelectrochemical properties of LaTiO2N electrodes prepared by particle transfer for sunlight-driven water splitting. Chem. Sci. 4, 1120–1124 (2013).

    Google Scholar 

  26. 26.

    Lin, F. et al. Photocatalytic oxidation of thiophene on BiVO4 with dual co-catalysts Pt and RuO2 under visible light irradiation using molecular oxygen as oxidant. Energy Environ. Sci. 5, 6400–6406 (2012).

    Google Scholar 

  27. 27.

    Ma, X. et al. Surface photovoltage spectroscopy observes sub-band-gap defects in hydrothermally synthesized SrTiO3 nanocrystals. J. Phys. Chem. C 123, 25081–25090 (2019).

    Google Scholar 

  28. 28.

    Leung, J. J. et al. Solar-driven reduction of aqueous CO2 with a cobalt bis(terpyridine)-based photocathode. Nat. Catal. 2, 354–365 (2019).

    Google Scholar 

  29. 29.

    Kudo, A., Omori, K. & Kato, H. A novel aqueous process for preparation of crystal form-controlled and highly crystalline BiVO4 powder from layered vanadates at room temperature and its photocatalytic and photophysical properties. J. Am. Chem. Soc. 121, 11459–11467 (1999).

    Google Scholar 

  30. 30.

    Chang, X. et al. Enhanced surface reaction kinetics and charge separation of p−n heterojunction Co3O4/BiVO4 photoanodes. J. Am. Chem. Soc. 137, 8356–8359 (2015).

    Google Scholar 

  31. 31.

    Bassegoda, A., Madden, C., Wakerley, D. W., Reisner, E. & Hirst., J. Reversible interconversion of CO2 and formate by a molybdenum-containing formate dehydrogenase. J. Am. Chem. Soc. 136, 15473–15476 (2014).

    Google Scholar 

  32. 32.

    Wakerley, D. W. & Reisner, E. Oxygen-tolerant proton reduction catalysis: much O2 about nothing? Energy Environ. Sci. 8, 2283–2295 (2015).

    Google Scholar 

  33. 33.

    Ryu, J., T. N. Andersen, T. N. & Eyring, H. The electrode reduction kinetics of carbon dioxide in aqueous solution. J. Phys. Chem. 76, 3278–3286 (1972).

    Google Scholar 

  34. 34.

    Akira, M. & Yoshio, H. Product selectivity affected by cationic species in electrochemical reduction of CO2 and CO at a Cu electrode. Bull. Chem. Soc. Jpn. 64, 123–127 (1991).

    Google Scholar 

  35. 35.

    Pérez-Gallent, E., Marcandalli, G., Figueiredo, M. C., Calle-Vallejo, F. & Koper, M. T. M. Structure- and potential-dependent cation effects on CO reduction at copper single-crystal electrodes. J. Am. Chem. Soc. 139, 16412–16419 (2017).

    Google Scholar 

  36. 36.

    Feng, S. et al. Enriched surface oxygen vacancies of photoanodes by photoetching with enhanced charge separation. Angew. Chem. Int. Ed. 59, 2044–2048 (2020).

    Google Scholar 

  37. 37.

    Hykaway, N., Sears, W. M., Morisaki, H. & Morrison, S. R. Current-doubling reactions on titanium dioxide photoanodes. J. Phys. Chem. 90, 6663–6667 (1986).

    Google Scholar 

  38. 38.

    Sekizawa, K., Sato, S., Arai, T. & Morikawa, T. Solar-driven photocatalytic CO2 reduction in water utilizing a ruthenium complex catalyst on p-type Fe2O3 with a multiheterojunction. ACS Catal. 8, 1405–1416 (2018).

    Google Scholar 

  39. 39.

    Leung, J. J., Vigil, J. A., Warnan, J., Edwardes Moore, E. & Reisner, E. Rational design of polymers for selective CO2 reduction catalysis. Angew. Chem. Int. Ed. 58, 7697–7701 (2019).

    Google Scholar 

  40. 40.

    Bélanger, D. & Jean Pinson, J. Electrografting: a powerful method for surface modification. Chem. Soc. Rev. 40, 3995–4048 (2011).

    Google Scholar 

  41. 41.

    Wang, Q. et al. Z-scheme water splitting using particulate semiconductors immobilized onto metal layers for efficient electron relay. J. Catal. 328, 308–315 (2015).

    Google Scholar 

  42. 42.

    Iwase, A., Ng, Y. H., Ishiguro, Y., Kudo, A. & Amal, R. Reduced graphene oxide as a solid-state electron mediator in Z-scheme photocatalytic water splitting under visible light. J. Am. Chem. Soc. 133, 11054–11057 (2011).

    Google Scholar 

  43. 43.

    Reisner, E. et al. Data Set for Molecularly Engineered Photocatalyst Sheet for Scalable Solar Formate Production from Carbon Dioxide and Water (Cambridge Data Repository, 2020);

  44. 44.

    Sasaki, Y., Iwase, A., Katoa, H. & Kudo, A. The effect of co-catalyst for Z-scheme photocatalysis systems with an Fe3+/Fe2+ electron mediator on overall water splitting under visible light irradiation. J. Catal. 259, 133–137 (2008).

    Google Scholar 

Download references


We thank C. Sahm and A. Eisenschmidt at the University of Cambridge for assisting with the isotopic labelling experiment, S. Roy and M. Rahaman at the University of Cambridge for helpful discussions, S. Young at the University of Cambridge for performing ICP–OES analysis, and M. Isaacs at HarwellXPS for carrying out XPS. This work was supported by EU Marie Sklodowska-Curie individual Fellowships (GAN 793996 to Q.W. and GAN 744317 to S.K.), European Commission Future and Emerging Technologies (FET) Open programme project SoFiA (GAN 828838 to S.R.-J. and E.R.), Christian Doppler Research Association (Austrian Federal Ministry for Digital and Economic Affairs and the National Foundation for Research, Technology and Development) and the OMV Group (to J.W. and E.R.). V.A. is grateful for the financial support from the Cambridge Trusts (Vice-Chancellor’s Award) and the Winton Programme for the Physics of Sustainability. J.J.L. is supported by the Woolf Fisher Trust in New Zealand. The XPS data collection was performed at the EPSRC National Facility for XPS (HarwellXPS)—operated by Cardiff University and University College London—under contract no. PR16195.

Author information




Q.W. and E.R. conceived the idea. E.R. supervised the project. J.W., J.J.L. and S.R.-J. synthesised and characterized CotpyP. Q.W. prepared the photocatalyst sheet and photoelectrodes and conducted physical characterizations and photo(electro)chemical experiments. S.K. carried out NMR spectroscopy, V.A. assisted with O2 quantification and scalability tests. All authors analysed the data, discussed the results and assisted with manuscript preparation.

Corresponding author

Correspondence to Erwin Reisner.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–11, Tables 1–4 and refs. 1–10.

Source data

Source Data Fig. 2

Numerical data used to generate graphs.

Source Data Fig. 3

Numerical data used to generate graphs.

Source Data Fig. 4

Numerical data used to generate graphs and statistical Source Data.

Source Data Fig. 5

Numerical data used to generate graphs.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Wang, Q., Warnan, J., Rodríguez-Jiménez, S. et al. Molecularly engineered photocatalyst sheet for scalable solar formate production from carbon dioxide and water. Nat Energy 5, 703–710 (2020).

Download citation


Sign up for the Nature Briefing newsletter for a daily update on COVID-19 science.
Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing