Highly Efficient Photoelectrochemical Synthesis of Ammonia Using Plasmon-Enhanced Black Silicon under Ambient Conditions

The photoelectrochemical (PEC) approach is attractive as a promising route for the nitrogen reduction reaction (NRR) toward ammonia (NH3) 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 N2 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 NH3 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.

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“…h) Comparison chart of FE with existing PEC NRR catalytic systems with present Au/PCN/ n + np + ‐ Si photocathode. [ 18,19,57,58 ]…”

Section: Resultsmentioning

confidence: 99%

“…[ 17 ] A few studies have recently been reported on PEC N 2 to NH 3 synthesis. [ 18,19 ] Ali et al. have demonstrated PEC NRR using Au nanoparticle‐decorated black Si photoelectrode and obtained an NH 3 production yield of 13.3 mg h –1 m –2 .…”

Section: Introductionmentioning

confidence: 99%

Optically and Electrocatalytically Decoupled Si Photocathodes with a Porous Carbon Nitride Catalyst for Nitrogen Reduction with Over 61.8% Faradaic Efficiency

Karthik

Vinoth

et al. 2021

Advanced Materials

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“…The SiIP wafers act as a substrate to be electrodeposited metal Co, and the materials were sulfurated using CVD to finish the fabrication of photocathodes. The optimized photocathodes had a well onset potential of 0.22 V, and the photocurrent density is 10.4 mA cm −2 at −0.45 V. In 2020, B. Wang et al [80] fabricated a plasmon-enhanced black silicon material to synthetic ammonia using photo-electrocatalysis. Through putting silicon into AgNO 3 and HF solution, the Ag nanoparticles and surface nanostructure of black silicon were formed, due to the catalysis of Ag + and the etching of HF.…”

Section: Photocatalysis and Photo-electrocatalysismentioning

confidence: 99%

Recent Progress of Black Silicon: From Fabrications to Applications

et al. 2020

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Since black silicon was discovered by coincidence, the special material was explored for many amazing material characteristics in optical, surface topography, and so on. Because of the material property, black silicon is applied in many spheres of a photodetector, photovoltaic cell, photo-electrocatalysis, antibacterial surfaces, and sensors. With the development of fabrication technology, black silicon has expanded in more and more applications and has become a research hotspot. Herein, this review systematically summarizes the fabricating method of black silicon, including nanosecond or femtosecond laser irradiation, metal-assisted chemical etching (MACE), reactive ion etching (RIE), wet chemical etching, electrochemical method, and plasma immersion ion implantation (PIII) methods. In addition, this review focuses on the progress in multiple black silicon applications in the past 10 years. Finally, the prospect of black silicon fabricating and various applications are outlined.

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“…The most commonly used experimental configuration for plasmon-enhanced NRR is a photocatalytic system in which the catalyst is either dispersed in a N 2 -saturated solution or deposited onto a substrate which is then immersed in the reaction solution. In a less frequently used experimental configuration for plasmon-enhanced NRR, an external bias can be applied to drive the reaction along with illumination (photoelectrochemical system); [42,43] however, this will not be covered in this review.…”

Section: Plasmonic Nanomaterials For Nrrmentioning

confidence: 99%

Photocatalytic Plasmon‐Enhanced Nitrogen Reduction to Ammonia

Monyoncho

Dasog

2021

Adv Energy and Sustain Res

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Nitrogen reduction to ammonia under ambient conditions is an emerging area of research sparked by the increasing concerns over climate change which is driving the efforts to find alternatives to energy‐intensive Haber–Bosch process. Ammonia is a critical component in the manufacturing of fertilizers and is required to support the global food supply. It can also be used as a fuel source to generate electricity. Many strategies have been used to drive nitrogen reduction under milder conditions including incorporation of plasmonic nanomaterials. The ability of plasmonic nanomaterials to strongly interact with light, resulting in near‐field enhancement, hot charge‐carrier generation and injection, increase in local temperature, has made them attractive candidates for catalysis. This review provides a comprehensive survey of recent developments in photocatalytic, plasmon‐enhanced nitrogen conversion to ammonia and the proposed mechanisms for the increased catalytic activity. A brief outlook on the current challenges and future directions is also provided.

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Highly Efficient Photoelectrochemical Synthesis of Ammonia Using Plasmon-Enhanced Black Silicon under Ambient Conditions

Cited by 37 publications

References 56 publications

Optically and Electrocatalytically Decoupled Si Photocathodes with a Porous Carbon Nitride Catalyst for Nitrogen Reduction with Over 61.8% Faradaic Efficiency

Optically and Electrocatalytically Decoupled Si Photocathodes with a Porous Carbon Nitride Catalyst for Nitrogen Reduction with Over 61.8% Faradaic Efficiency

Recent Progress of Black Silicon: From Fabrications to Applications

Photocatalytic Plasmon‐Enhanced Nitrogen Reduction to Ammonia

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