Optically and Electrocatalytically Decoupled Si Photocathodes with a Porous Carbon Nitride Catalyst for Nitrogen Reduction with Over 61.8% Faradaic Efficiency
KAUST DepartmentChemical Science Program
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
Homogeneous Catalysis Laboratory (HCL)
KAUST Catalysis Center (KCC)
KAUST Solar Center (KSC)
Material Science and Engineering Program
Nano Energy Lab
Physical Science and Engineering (PSE) Division
KAUST Grant NumberOSR-2018-CARF/CCF-3079
Embargo End Date2022-03-31
Permanent link to this recordhttp://hdl.handle.net/10754/668503
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AbstractThe photoelectrochemical (PEC) approach is attractive as a promising route for the nitrogen reduction reaction (NRR) toward ammonia (NH<sub>3</sub> ) synthesis. However, the challenges in synergistic management of optical, electrical, and catalytic properties have limited the efficiency of PEC NRR devices. Herein, to enhance light-harvesting, carrier separation/transport, and the catalytic reactions, a concept of decoupling light-harvesting and electrocatalysis by employing a cascade n<sup>+</sup> np<sup>+</sup> -Si photocathode is implemented. Such a decoupling design not only abolishes the parasitic light blocking but also concurrently improves the optical and electrical properties of the n<sup>+</sup> np<sup>+</sup> -Si photocathode without compromising the efficiency. Experimental and density functional theory studies reveal that the porous architecture and N-vacancies promote N<sub>2</sub> adsorption of the Au/porous carbon nitride (PCN) catalyst. Impressively, an n<sup>+</sup> np<sup>+</sup> -Si photocathode integrating the Au/PCN catalyst exhibits an outstanding PEC NRR performance with maximum Faradaic efficiency (FE) of 61.8% and NH<sub>3</sub> production yield of 13.8 µg h<sup>-1</sup> cm<sup>-2</sup> at -0.10 V versus reversible hydrogen electrode (RHE), which is the highest FE at low applied potential ever reported for the PEC NRR.
CitationPeramaiah, K., Ramalingam, V., Fu, H., Alsabban, M. M., Ahmad, R., Cavallo, L., … He, J. (2021). Optically and Electrocatalytically Decoupled Si Photocathodes with a Porous Carbon Nitride Catalyst for Nitrogen Reduction with Over 61.8% Faradaic Efficiency. Advanced Materials, 2100812. doi:10.1002/adma.202100812
SponsorsK.P. and V.R. contributed equally to this work. This work was supported by the King Abdullah University of Science and Technology (KAUST) and City University of Hong Kong. V.T. is indebted to the support from the KAUST Office of Sponsored Research (OSR) under award no. OSR-2018-CARF/CCF-3079. R.A. and L.C. acknowledge the Supercomputing Laboratory at KAUST for computational resources (Cray XC40, ShaheenII).
CollectionsArticles; Physical Science and Engineering (PSE) Division; Electrical Engineering Program; Chemical Science Program; Material Science and Engineering Program; KAUST Catalysis Center (KCC); KAUST Solar Center (KSC); Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
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