Fig. 2: Origin of stable performance of the NiFeCo/Ni/Cl:FAPbI3(ETLs) photoanodes.
From: Scalable and durable module-sized artificial leaf with a solar-to-hydrogen efficiency over 10%
a Chemical stability (J–E) curves showing LSV plots of NiFeCo/Ni/Cl:FAPbI3(TiO2) (green color) and NiFeCo/Ni/Cl:FAPbI3(Cl:SnO2) (blue color) photoanodes measured in 1 M KOH (pH 14) electrolyte after immersing them in the electrolyte for continuous 5 days in dark and recording the J–E curves in light once per day. b Photocorrosion was measured with and without a sacrificial agent (0.2 M Na2SO3) to see if there was charge-accumulation at the surface without being consumed. Photocorrosion tests were conducted at applied voltage with highest %ABPE, i.e., 0.78 VRHE for NiFeCo/Ni/Cl:FAPbI3(TiO2) (green color) and 0.64 VRHE for NiFeCo/Ni/Cl:FAPbI3(Cl:SnO2) (blue color) photoanodes. c Photostability under continuous illumination with and without a UV cut-off filter. These three stability tests were conducted in a PEC reactor without O-ring. d Extended long-term stability measurements of NiFeCo/Ni/Cl:FAPbI3(TiO2) (green color) and NiFeCo/Ni/Cl:FAPbI3(Cl:SnO2) (blue color) photoanodes at 1.23 VRHE for 140 h. The measurement was performed in an O-ring type PEC reactor (inset photographs) where only NiFeCo/Ni anode is exposed to electrolyte while epoxy bond and PSK layers do not directly contact with electrolyte. Light was illuminated from the backside of the O-ring type PEC reactor. e Absorbance spectra of the NiFeCo/Ni/Cl:FAPbI3(Cl:SnO2) photoanode measured before and after the stability test. The absorbance measurement was conducted through diffusive reflectance spectroscopy (DRS) from back side (PSK side) in wavelengths of 550–875 nm, because the front side is integrated with catalyst. f Stability and photocurrent density of our NiFeCo/Ni/Cl:FAPbI3(Cl:SnO2) photoanode compared with reported state-of-the-art PSK photoanodes (FeNi/Ni/FAMACsPbIBr346, NiFe/Ni/CCP/FAMAPbI376, NiFe/Ni/carbon/FAMAPbI359, Ni/Graphite/FACsPbBrI377, Carbon/Ag/MAPbI378, Ni/Ag/MAPbI379). The “tx” in graph indicates the time till x% of the photocurrent generation is retained (See Table S4 for detail). All PEC measurements were conducted using a 3-electrode set-up at a scan rate of 10 mV s−1 in 1 M KOH (pH 14) unless specified otherwise under the 1-sun (AM 1.5 G) illumination.
