Semi Transparent Three-Dimensional Macroporous Quaternary Oxynitride Photoanodes for Photoelectrochemical Water Oxidation

Chemistry of Materials, vol. 34, pp. 6902–6911

Abstract

Semi transparent three-dimensional macroporous (3DM) photoanodes based on quaternary oxynitrides have the potential to simultaneously realize superior light harvesting and efficient charge transfer in a tandem photoelectrochemical (PEC) cell. A 3DM CaTaO 2 N photoanode was prepared for the first time on a GaN/Al 2 O 3 substrate via a chemical route, and it exhibits a high transmittance of >60% in the wide solar spectrum and a photoresponse onset at −0.3 V versus the reversible hydrogen electrode ( V RHE ) under simulated solar illumination. In particular, a plateau photocurrent density of 0.21 mA cm –2 was achieved at a low potential of 0.4 V RHE, which was 1.6-fold and more than 50-fold higher than a two-dimensional macroporous (2DM) CaTaO 2 N/GaN/Al 2 O 3 photoanode and a conventional particle-based CaTaO 2 N/GaN/Al 2 O 3 photoanode, respectively. The bicontinuous, interconnected pore structure within this 3DM film can improve charge carrier separation and collection by reducing the average diffusion distance for minority carriers toward the electrolyte. Optical measurements and simulations verified the enhanced sunlight harvesting in the 3DM photoanode, which was ascribed to the concentrated distribution of the electric field and multiple scattering. This study provides guidance for future synthesis of highly efficient semitransparent 3DM quaternary oxynitride-based photoanodes for a tandem PEC device.

Authors 11

1. Can Lu Aachen Institute of Inorganic Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Inorganic Chemistry, RWTH Aachen University, Aachen D-52056, Germany

2. Jianhong Chen

   Stockholm University

   Affiliation as printed

   Department of Materials and Environmental Chemistry, Stockholm University, Stockholm 10691, Sweden

3. Karolina Piętak

   Warsaw University of Technology · Łukasiewicz Research Network - Institute of Microelectronics and Photonics

   Affiliation as printed

   Faculty of Chemistry, Warsaw University of Technology, Warsaw 00-664, Poland

   Łukasiewicz Research Network-Institute of Microelectronics and Photonics, Warsaw 02-668, Poland

4. Anna Rokicińska

   Jagiellonian University

   Affiliation as printed

   Faculty of Chemistry, Jagiellonian University, Krakow 30-387, Poland

5. Piotr Kuśtrowski

   Jagiellonian University

   Affiliation as printed

   Faculty of Chemistry, Jagiellonian University, Krakow 30-387, Poland

6. Richard Dronskowski Aachen Institute of Inorganic Chemistry

   Shenzhen Polytechnic University · RWTH Aachen University

   Affiliation as printed

   Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic, Shenzhen 518055, China

   Institute of Inorganic Chemistry, RWTH Aachen University, Aachen D-52056, Germany

7. Jiayin Yuan

   Stockholm University

   Affiliation as printed

   Department of Materials and Environmental Chemistry, Stockholm University, Stockholm 10691, Sweden

8. Serhiy Budnyk

   AC2T Research (Austria)

   Affiliation as printed

   AC2T Research GmbH, Viktor-Kaplan-Str. 2c, Wiener Neustadt 2700, Austria

9. Sebastian Złotnik

   Military University of Technology in Warsaw · Łukasiewicz Research Network - Institute of Microelectronics and Photonics

   Affiliation as printed

   Institute of Applied Physics, Military University of Technology, Warsaw 00-908, Poland

   Łukasiewicz Research Network-Institute of Microelectronics and Photonics, Warsaw 02-668, Poland

10. Robert Henry Coridan

    University of Arkansas at Fayetteville

    Affiliation as printed

    Department of Chemistry and Biochemistry and the Materials Science and Engineering Program, University of Arkansas, Fayetteville 72701, Arkansas, USA

11. Adam Slabon corresponding

    University of Wuppertal

    Affiliation as printed

    Chair of Inorganic Chemistry, University of Wuppertal, Wuppertal D-42119, Germany