Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Spatial decoupling of light absorption and catalytic activity of Ni–Mo-loaded high-aspect-ratio silicon microwire photocathodes


A solar-driven photoelectrochemical cell provides a promising approach to enable the large-scale conversion and storage of solar energy, but requires the use of Earth-abundant materials. Earth-abundant catalysts for the hydrogen evolution reaction, for example nickel–molybdenum (Ni–Mo), are generally opaque and require high mass loading to obtain high catalytic activity, which in turn leads to parasitic light absorption for the underlying photoabsorber (for example silicon), thus limiting production of hydrogen. Here, we show the fabrication of a highly efficient photocathode by spatially and functionally decoupling light absorption and catalytic activity. Varying the fraction of catalyst coverage over the microwires, and the pitch between the microwires, makes it possible to deconvolute the contributions of catalytic activity and light absorption to the overall device performance. This approach provided a silicon microwire photocathode that exhibited a near-ideal short-circuit photocurrent density of 35.5 mA cm−2, a photovoltage of 495 mV and a fill factor of 62% under AM 1.5G illumination, resulting in an ideal regenerative cell efficiency of 10.8%.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Electrodeposition of Earth-abundant catalysts, Ni–Mo, on Si microwire arrays with a radial junction.
Fig. 2: Photoelectrical J–V measurements of Si microwire arrays with radial n+/p-junctions.
Fig. 3: Current density J ph versus potential for Si microwire array devices with radial n+/p-junctions measured in cyclic potential sweeps.
Fig. 4: Deconvolution of catalytic activity and light-absorption losses in a Si microwire photocathode.


  1. Walter, M. G. et al. Solar water splitting cells. Chem. Rev. 110, 6446–6473 (2010).

    Article  Google Scholar 

  2. Shaner, M. R., McKone, J. R., Gray, H. B. & Lewis, N. S. Functional integration of Ni–Mo electrocatalysts with Si microwire array photocathodes to simultaneously achieve high fill factors and light-limited photocurrent densities for solar-driven hydrogen evolution. Energy Environ. Sci. 8, 2977–2984 (2015).

    Article  Google Scholar 

  3. Roske, C. W. et al. Comparison of the performance of CoP-coated and Pt-coated radial junction n+p-silicon microwire-array photocathodes for the sunlight-driven reduction of water to H2(g). J. Phys. Chem. Lett. 6, 1679–1683 (2015).

    Article  Google Scholar 

  4. Coridan, R. H. et al. Methods for comparing the performance of energy-conversion systems for use in solar fuels and solar electricity generation. Energy Environ. Sci. 8, 2886–2901 (2015).

    Article  Google Scholar 

  5. Battaglia, C., Cuevas, A. & De Wolf, S. High-efficiency crystalline silicon solar cells: status and perspectives. Energy Environ. Sci. 9, 1552–1576 (2016).

    Article  Google Scholar 

  6. Vijselaar, W., Elbersen, R., Tiggelaar, R. M., Gardeniers, H. & Huskens, J. Photo-electrical characterization of silicon micropillar arrays with radial p/n junctions containing passivation and anti-reflection coatings. Adv. Energy Mater. 7, 1601497 (2016).

    Article  Google Scholar 

  7. Chen, Y. K., Sun, K., Audesirk, H., Xiang, C. X. & Lewis, N. S. A quantitative analysis of the efficiency of solar-driven water-splitting device designs based on tandem photoabsorbers patterned with islands of metallic electrocatalysts. Energy Environ. Sci. 8, 1736–1747 (2015).

    Article  Google Scholar 

  8. Elbersen, R. et al. Controlled doping methods for radial p/n junctions in silicon. Adv. Energy Mater. 5, 1401745–1401753 (2015).

    Article  Google Scholar 

  9. Elbersen, R., Vijselaar, W., Tiggelaar, R. M., Gardeniers, H. & Huskens, J. Effects of pillar height and junction depth on the performance of radially doped silicon pillar arrays for solar energy applications. Adv. Energy Mater. 6, 1501728 (2016).

    Article  Google Scholar 

  10. Nickel Plating Handbook Vol. 1, 80 (Nickel Institute, Toronto, Canada, 2014).

  11. McKone, J. R. et al. Evaluation of Pt, Ni, and Ni–Mo electrocatalysts for hydrogen evolution on crystalline Si electrodes. Energy Environ. Sci. 4, 3573–3583 (2011).

    Article  Google Scholar 

  12. Warren, E. L., McKone, J. R., Atwater, H. A., Gray, H. B. & Lewis, N. S. Hydrogen-evolution characteristics of Ni-Mo-coated, radial junction, n + p-silicon microwire array photocathodes. Energy Environ. Sci. 5, 9653–9661 (2012).

    Article  Google Scholar 

  13. Hoare, J. P. Boric-acid as a catalyst in nickel plating solutions. J. Electrochem. Soc. 134, 3102–3103 (1987).

    Article  Google Scholar 

  14. Fan, C., Piron, D. L., Sleb, A. & Paradis, P. Study of electrodeposited nickel–molybdenum, nickel–tungsten, cobalt–molybdenum, and cobalt–tungsten as hydrogen electrodes in alkaline water electrolysis. J. Electrochem. Soc. 141, 382–387 (1994).

    Article  Google Scholar 

  15. Podlaha, E. J. & Landolt, D. Induced codeposition. I. An experimental investigation of Ni–Mo alloys. J. Electrochem. Soc. 143, 885––892 (1996).

    Article  Google Scholar 

  16. Podlaha, E. J. & Landolt, D. Induced codeposition. II. A mathematical model describing the electrodeposition of Ni–Mo alloys. J. Electrochem. Soc. 143, 893–899 (1996).

    Article  Google Scholar 

  17. Podlaha, E. J. & Landolt, D. Induced codeposition. III. Molybdenum alloys with nickel, cobalt, and iron. J. Electrochem. Soc. 144, 1672–1680 (1997).

    Article  Google Scholar 

  18. Chen, Y., Shen, J. & Chen, N. X. The effect of Mo atoms in ternary nitrides with eta-type structure. Solid State Commun. 149, 121–125 (2009).

    Article  Google Scholar 

  19. Mishima, Y., Ochiai, S. & Suzuki, T. Lattice parameters of Ni(γ), Ni3Al(γ′), and Ni3Ga(γ′) solid solutions with the additions of transition and B-subgroup elements. Acta Metallurgica 33, 1161–1196 (1985).

    Article  Google Scholar 

  20. Schultz, O., Mette, A., Hermle, M. & Glunz, S. W. Thermal oxidation for crystalline silicon solar cells exceeding 19% efficiency applying industrially feasible process technology. Prog. Photovoltaics 16, 317–324 (2008).

    Article  Google Scholar 

  21. Benick, J., Zimmermann, K., Spiegelman, J., Hermle, M. & Glunz, S. W. Rear side passivation of PERC-type solar cells by wet oxides grown from purified steam. Prog. Photovoltaics 19, 361–365 (2011).

    Article  Google Scholar 

  22. Mack, S. et al. Properties of purified direct steam grown silicon thermal oxides. Sol. Energy Mater. Sol. Cells 95, 2570–2575 (2011).

    Article  Google Scholar 

  23. Garcia-Esparza, A. T. & Takanabe, K. A simplified theoretical guideline for overall water splitting using photocatalyst particles. J. Mat. Chem. A 4, 2894–2908 (2016).

    Article  Google Scholar 

  24. Westerik, P. J. et al. Sidewall patterning — a new wafer-scale method for accurate patterning of vertical silicon structures. J. Micromech. Microeng. 28, 015008 (2017).

  25. Green, M. A. Accuracy of analytical expressions for solar cell fill factors. Solar Cells 7, 337–340 (1982).

    Article  Google Scholar 

  26. Kim, J. H. et al. Hetero-type dual photoanodes for unbiased solar water splitting with extended light harvesting. Nat. Commun. 7, 13380 (2016).

    Article  Google Scholar 

  27. Vermaas, D. A., Sassenburg, M. & Smith, W. A. Photo-assisted water splitting with bipolar membrane induced pH gradients for practical solar fuel devices. J. Mat. Chem. A 3, 19556–19562 (2015).

    Article  Google Scholar 

  28. Veldhuizen, L. W., Vijselaar, W. J. C., Gatz, H. A., Huskens, J. & Schropp, R. E. I. Textured and micropillar silicon heterojunction solar cells with hot-wire deposited passivation layers. Thin Solid. Films 635, 66–72 (2017).

    Article  Google Scholar 

  29. Hale, G. M. & Querry, M. R. Optical constants of water in the 200-nm to 200-μm wavelength region. Appl. Opt. 12, 555–563 (1973).

    Article  Google Scholar 

  30. Boettcher, S. W. et al. Photoelectrochemical hydrogen evolution using Si microwire arrays. J. Am. Chem. Soc. 133, 1216–1219 (2011).

    Article  Google Scholar 

  31. Huang, Z. et al. Ni12P5 nanoparticles as an efficient catalyst for hydrogen generation via electrolysis and photoelectrolysis. ACS Nano 8, 8121–8129 (2014).

    Article  Google Scholar 

  32. Bao, X. Q., Fatima Cerqueira, M., Alpuim, P. & Liu, L. Silicon nanowire arrays coupled with cobalt phosphide spheres as low-cost photocathodes for efficient solar hydrogen evolution. Chem. Commun. 51, 10742–10745 (2015).

    Article  Google Scholar 

  33. Lv, C. et al. Silicon nanowires loaded with iron phosphide for effective solar-driven hydrogen production. J. Mat. Chem. A 3, 17669–17675 (2015).

    Article  Google Scholar 

Download references


The Netherlands Organization for Scientific Research (NWO) is acknowledged for financial support (FOM projects 13CO12-1 and 13CO12-2, and MESA+ School for Nanotechnology grant 022.003.001). A. Milbrat and G. Mul are acknowledged for assistance with the gas chromatography measurements.

Author information

Authors and Affiliations



W.V., P.W., J.V. and E.B. performed the experimental work, W.V., P.W., N.R.T. and R.M.T. planned the project and performed the data analysis, W.V., H.G. and J.H. conceived the idea, and all authors contributed to the writing of the manuscript.

Corresponding authors

Correspondence to Han Gardeniers or Jurriaan Huskens.

Ethics declarations

Competing interests

The authors declare no competing financial 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 Figures 1–17, Supplementary Tables 1–5, Supplementary Discussion and Supplementary References

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Vijselaar, W., Westerik, P., Veerbeek, J. et al. Spatial decoupling of light absorption and catalytic activity of Ni–Mo-loaded high-aspect-ratio silicon microwire photocathodes. Nat Energy 3, 185–192 (2018).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

Further reading


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing