Dispersed Ni Nanoparticles Stabilize Silicon Photoanodes for Efficient and Inexpensive Sunlight-Assisted Water Oxidation

Abstract

International audienceNi electrodeposited on n-type Si from aqueous solutions in the form of isolated or coalescent nanoparticles (NPs) protects the underlying and partially exposed Si from photocorrosion-induced electrical passivation. Such photoanodes, fabricated without the need for additional protecting layers, a buried junction, and high vacuum techniques, show a high photovoltage of similar to 500 mV for the oxygen evolution reaction (OER), state-of-the-art photocurrents, and faradaic efficiencies > 90% under AM 1.5G illumination conditions at pH 14. Remarkably, these photoelectrodes are stable and can be operated at the light limited catalytic current from 10 h to more than 40 h in 1 M NaOH. These findings demonstrate that robust and efficient Si-based photoanodes can be produced easily, which opens new opportunities for the implementation of low-cost Si-based monolithic photoelectrochemical cells for efficient solar fuel production

Rational Design and Construction of Cocatalysts for Semiconductor‐Based Photo‐Electrochemical Oxygen Evolution: A Comprehensive Review

“…Furthermore, nickel, [240][241][242][243][244] as a member of non-noble metal family, is capable of resisting photocorrosion and providing high OER activity. Furthermore, nickel, [240][241][242][243][244] as a member of non-noble metal family, is capable of resisting photocorrosion and providing high OER activity.…”

Silicon Photoanodes Partially Covered by Ni@Ni(OH)2 Core–Shell Particles for Photoelectrochemical Water Oxidation

“…The Ni(OH) 2 is derived from electrochemical corrosion by the stronga lkaline electrolyte. [20] However, the HR-TEMi mages of the shell region did not reveal the presence of ac rystal lattice.T his implies that the coreshell particles of n-Si/SiO x /Ni@Ni(OH) 2 were composed of crystalline Ni particles coated by amorphous Ni(OH) 2 shells. 50 nm;F igure 1h,i).…”

“…[1] Photocatalytic or photoelectrochemical (PEC) water splitting into hydrogen fuels are promising strategies to use solar energy to address this globalc hallenge. [15] Dispersing high-work-function Co [19] and Ni [20] nanoparticles on the surface of Si/SiO x photoanodes successfully reduces the light-absorption loss within MIS architectures. [8][9][10] Undecorateds ilicon photoanodes are capable of producing only meager photocurrentd ensities on the order of microamperes per square centimeter (mAcm À2 ), which are unstable and quickly dissipate in minutes in aqueouss olution, especiallya te levated pH values.…”

“…Using am etal (e.g.,N i, [15] Co, [16] or Ir [17] )o rametal oxide with ah igh work function( e.g.,I n-doped SnO 2 ) [18] to construct am etal-insulator-semiconductor (MIS) structurec an significantly promote the charge separation owing to the increasedb and bending in the depletion region.Ac hallenge is to optimize the thickness of the high-work-function metal layer to balance light absorption with efficient hole extraction and hole transfer,asr ecently demonstrated for Si/SiO x /Ni. [15] Dispersing high-work-function Co [19] and Ni [20] nanoparticles on the surface of Si/SiO x photoanodes successfully reduces the light-absorption loss within MIS architectures. [21] Ultrathin shell layers of metal oxyhydroxidesf ormed duringw ater oxidation in alkali solutionsa saresult of electrochemical corrosiono n the surfaceo fm etal particles.…”

Tunable Electrodeposition of Ni Electrocatalysts onto Si Microwires Array for Photoelectrochemical Water Oxidation

“…Therefore, the transition‐metal/metal oxides electrocatalysts fabricated as protection layer by thin‐film deposition techniques including spin‐coating, sputtering, electron beam evaporation, and atomic layer deposition (ALD) that also acted as electrocatalytic layer were widely investigated. Ni‐based thin films act as electrocatalysts were widely studied for electrochemical water oxidation because of their earth abundance and low cost . Although various controllable and cheap approaches have been successfully developed to fabricate electrocatalyst onto photoanodes without high‐vacuum equipment for ultrathin layer deposition, only few studies toward Ni‐based electrocatalysts were employed for PEC device so far …”