Photo-assisted decoration of Ag-Pt nanoparticles on Si photocathodes for reducing overpotential toward enhanced photoelectrochemical water splitting

Abstract

Developing new catalysts to decorate photoelectrodes has been widely used to enhance the performance of photoelectrochemical (PEC) cells. However, the high cost, complex synthesis, and poor stability of catalyst decoration strongly hinder its practical application. Here, we report a facile and low-cost decoration of Ag-Pt nanoparticles (Ag-Pt NPs) on Si photocathodes with TiO 2 /Ti sacrificial overlayers. Such a decoration does not rely on any metallic-ion precursor solution since it is formed automatically via galvanic replacement reactions during PEC measurements; that is, Ti is displaced by Ag + and Pt 2+ ions, which are from the employed reference and counter electrodes, respectively. The as-decorated Ag-Pt NPs are verified to significantly enhance the hydrogen evolution reduction kinetics without substantially degrading the optical performance of Si photocathodes. Owing to optoelectronic advantages, the overpotential required to maintain a photocurrent density of 10 mA cm −2 (under AM 1.5G illumination) is reduced from −0.8 V RHE (for the bare planar Si photocathode) to −0.1 V RHE (for the planar Si photocathode with Ag-Pt NP decoration). Moreover, a further anodic shift (to 0 V RHE ) is visible for the Si nanowire array photocathode with Ag-Pt NP decoration, along with high long-term stability of the PEC response in acidic and neutral electrolytes. This study opens a new opportunity for the photo-assisted decoration of various alloy NPs on the morphology-varying photoelectrodes with different applications.

Accessing complex reconstructed material structures with hybrid global optimization acceleratedviaon-the-fly machine learning

“…Pt can undergo irreversible restructuring under reaction conditions, due to the surface oxidation and subsequent Pt dissolution, which is thought to decrease catalytic efficiency and durability. 19,69–72 However, the atomic-level modeling of the Pt oxidation remains uncertain. 73…”

“…Pt can undergo irreversible restructuring under reaction conditions, due to the surface oxidation and subsequent Pt dissolution, which is thought to decrease catalytic efficiency and durability. 19,[69][70][71][72] However, the atomic-level modeling of the Pt oxidation remains uncertain. 73 The optimized structures of 0.75 ML O-Pt(111), which are thought to exist at around 1.0-1.2 V RHE during electro-oxidation, 73,76 are shown in Fig.…”

Investigation of in situ sulfide/nitride/phosphide treatments of hematite photoanodes for improved solar water oxidation

“…In recent years, the application of photoelectrochemical technology to split water into hydrogen and oxygen has attracted widespread attention and has become one of the effective strategies to solve the current energy and environmental crisis. 1 Since Fujishima and Honda first used TiO 2 as a photoanode for photoelectrochemical water splitting (PEC-WS), 2 exploiting semiconductor materials (BiVO 4 , 3 Si, 4 hematite (α-Fe 2 O 3 ) 5 and CdS 6 ) has attracted widespread attention for photoelectrochemically converting water into hydrogen and oxygen. α-Fe 2 O 3 , an n-type semiconductor with a suitable band gap and wide absorption range, has proven to be an ideal photoanode candidate for PEC-WS systems.…”