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Optically and Electrocatalytically Decoupled Si Photocathodes with a Porous Carbon Nitride Catalyst for Nitrogen Reduction with Over 61.8% Faradaic Efficiency
Author(s) -
Peramaiah Karthik,
Ramalingam Vinoth,
Fu HuiChun,
Alsabban Merfat M.,
Ahmad Rafia,
Cavallo Luigi,
Tung Vincent,
Huang KuoWei,
He JrHau
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202100812
Subject(s) - photocathode , faraday efficiency , materials science , catalysis , reversible hydrogen electrode , electrocatalyst , carbon nitride , ammonia production , nitride , chemical engineering , photocatalysis , water splitting , nanotechnology , electrochemistry , electrode , chemistry , working electrode , layer (electronics) , organic chemistry , physics , quantum mechanics , engineering , electron
The photoelectrochemical (PEC) approach is attractive as a promising route for the nitrogen reduction reaction (NRR) toward ammonia (NH 3 ) 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 + np + ‐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 + np + ‐Si photocathode without compromising the efficiency. Experimental and density functional theory studies reveal that the porous architecture and N‐vacancies promote N 2 adsorption of the Au/porous carbon nitride (PCN) catalyst. Impressively, an n + np + ‐Si photocathode integrating the Au/PCN catalyst exhibits an outstanding PEC NRR performance with maximum Faradaic efficiency (FE) of 61.8% and NH 3 production yield of 13.8 µg h –1 cm –2 at −0.10 V versus reversible hydrogen electrode (RHE), which is the highest FE at low applied potential ever reported for the PEC NRR.