Efficient solar water splitting by enhanced charge separation in a bismuth vanadate-silicon tandem photoelectrode

Metal oxides are generally very stable in aqueous solutions and cheap, but their photochemical activity is usually limited by poor charge carrier separation. Here we show that this problem can be solved by introducing a gradient dopant concentration in the metal oxide film, thereby creating a distributed n(+)-n homojunction. This concept is demonstrated with a low-cost, spray-deposited and non-porous tungsten-doped bismuth vanadate photoanode in which carrier-separation efficiencies of up to 80% are achieved. By combining this state-of-the-art photoanode with an earth-abundant cobalt phosphate water-oxidation catalyst and a double- or single-junction amorphous Si solar cell in a tandem configuration, stable short-circuit water-splitting photocurrents of ~4 and 3 mA cm(-2), respectively, are achieved under 1 sun illumination. The 4 mA cm(-2) photocurrent corresponds to a solar-to-hydrogen efficiency of 4.9%, which is the highest efficiency yet reported for a stand-alone water-splitting device based on a metal oxide photoanode.

[1]  E. L. Miller,et al.  Status of research on tungsten oxide-based photoelectrochemical devices at the University of Hawai'i , 2010, Optics + Photonics for Sustainable Energy.

[2]  C. Mullins,et al.  Incorporation of Mo and W into nanostructured BiVO4 films for efficient photoelectrochemical water oxidation. , 2012, Physical chemistry chemical physics : PCCP.

[3]  Jong Hyeok Park,et al.  Photoelectrochemical cells with tungsten trioxide/Mo-doped BiVO4 bilayers. , 2012, Physical chemistry chemical physics : PCCP.

[4]  Roel van de Krol,et al.  Highly Improved Quantum Efficiencies for Thin Film BiVO4 Photoanodes , 2011 .

[5]  Kyoung-Shin Choi,et al.  Efficient and stable photo-oxidation of water by a bismuth vanadate photoanode coupled with an iron oxyhydroxide oxygen evolution catalyst. , 2012, Journal of the American Chemical Society.

[6]  A. Rothwarf,et al.  Interface charging and solar‐cell characteristics: CuInSe2/CdS , 1985 .

[7]  Michael Grätzel,et al.  Photoelectrochemical cells , 2001, Nature.

[8]  D. Nocera,et al.  Wireless Solar Water Splitting Using Silicon-Based Semiconductors and Earth-Abundant Catalysts , 2011, Science.

[9]  J. Fossum Physical operation of back-surface-field silicon solar cells , 1977, IEEE Transactions on Electron Devices.

[10]  F. Abdi,et al.  Spray-deposited Co-Pi Catalyzed BiVO 4 : a low-cost route towards highly efficient photoanodes , 2012 .

[11]  S. Linic,et al.  Plasmonic-metal nanostructures for efficient conversion of solar to chemical energy. , 2011, Nature materials.

[12]  D. Gamelin,et al.  Near-complete suppression of surface recombination in solar photoelectrolysis by "Co-Pi" catalyst-modified W:BiVO4. , 2011, Journal of the American Chemical Society.

[13]  Hideki Kato,et al.  Photocatalytic O2 evolution under visible light irradiation on BiVO4 in aqueous AgNO3 solution , 1998 .

[14]  E. Thimsen,et al.  Plasmonic solar water splitting , 2012 .

[15]  Hubertus V. M. Hamelers,et al.  Performance of metal alloys as hydrogen evolution reaction catalysts in a microbial electrolysis cell , 2011 .

[16]  M. Grätzel Photoelectrochemical cells : Materials for clean energy , 2001 .

[17]  M. Grätzel,et al.  Probing the photoelectrochemical properties of hematite (α-Fe2O3) electrodes using hydrogen peroxide as a hole scavenger , 2011 .

[18]  Jan Augustynski,et al.  Highly efficient water splitting by a dual-absorber tandem cell , 2012, Nature Photonics.

[19]  Roel van de Krol,et al.  Nature and Light Dependence of Bulk Recombination in Co-Pi-Catalyzed BiVO4 Photoanodes , 2012 .

[20]  J. Bockris,et al.  Thin film photoelectrochemistry: Iron oxide , 1984 .

[21]  Michael Grätzel,et al.  Light-induced water splitting with hematite: improved nanostructure and iridium oxide catalysis. , 2010, Angewandte Chemie.

[22]  K. Sayama,et al.  Highly efficient photoelectrochemical water splitting using a thin film photoanode of BiVO4/SnO2/WO3 multi-composite in a carbonate electrolyte. , 2012, Chemical communications.

[23]  Tetsuo Soga,et al.  Efficient Solar Water Splitting, Exemplified by RuO2-Catalyzed AlGaAs/Si Photoelectrolysis. , 2001 .

[24]  R. Rocheleau,et al.  Optimization of Hybrid Photoelectrodes for Solar Water-Splitting , 2005 .

[25]  Jun-Ho Yum,et al.  Examining architectures of photoanode–photovoltaic tandem cells for solar water splitting , 2010 .

[26]  A. Kudo,et al.  Selective Preparation of Monoclinic and Tetragonal BiVO4 with Scheelite Structure and Their Photocatalytic Properties. , 2002 .

[27]  Eiji Suzuki,et al.  One chip photovoltaic water electrolysis device , 2003 .

[28]  Jae Sung Lee,et al.  Heterojunction BiVO4/WO3 electrodes for enhanced photoactivity of water oxidation , 2011 .

[29]  Michael Grätzel,et al.  Solar water splitting: progress using hematite (α-Fe(2) O(3) ) photoelectrodes. , 2011, ChemSusChem.

[30]  P. Kulesza,et al.  Metal oxide photoanodes for solar hydrogen production , 2008 .

[31]  Daniel G. Nocera,et al.  In Situ Formation of an Oxygen-Evolving Catalyst in Neutral Water Containing Phosphate and Co2+ , 2008, Science.

[32]  Turner,et al.  A monolithic photovoltaic-photoelectrochemical device for hydrogen production via water splitting , 1998, Science.

[33]  Marc T. M. Koper,et al.  Thermodynamic theory of multi-electron transfer reactions: Implications for electrocatalysis , 2011 .

[34]  Iron oxide. , 1968, American Industrial Hygiene Association journal.

[35]  F. Abdi,et al.  Efficient BiVO4 Thin Film Photoanodes Modified with Cobalt Phosphate Catalyst and W‐doping , 2013 .

[36]  Tao Yu,et al.  Solar hydrogen generation from seawater with a modified BiVO4 photoanode , 2011 .

[37]  Michael Grätzel,et al.  Visible light-induced water oxidation on mesoscopic α-Fe2O3 films made by ultrasonic spray pyrolysis , 2005 .

[38]  M. Grätzel,et al.  Visible light-induced water oxidation on mesoscopic alpha-Fe2O3 films made by ultrasonic spray pyrolysis. , 2005, The journal of physical chemistry. B.

[39]  A. Kudo,et al.  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 , 1999 .

[40]  John O’M. Bockris,et al.  A one-unit photovoltaic electrolysis system based on a triple stack of amorphous silicon (pin) cells , 1985 .

[41]  T. Furtak,et al.  Cobalt-phosphate (Co-Pi) catalyst modified Mo-doped BiVO4 photoelectrodes for solar water oxidation , 2011 .

[42]  M. Saad,et al.  Effect of interface recombination on solar cell parameters , 2003 .