F 4600 spectrofluorometer

All reagents were of commercially analytical grade and used directly.
Fluorescent spectra were recorded using a Hitachi F-4600 spectrofluorometer (Tokyo, Japan), and UV-Vis spectra were determined on a Hitachi U-2910 spectrophotometer. ¹H- and ¹³C-NMR spectra were carried out with a Brucker AV 400 nuclear magnetic resonance instrument (Faellanden, Switzerland), and the chemical shift is given in ppm from tetramethylsilane (TMS). Mass spectra were obtained using a thermo TSQ Quantum Access Agilent 1100 mass spectrometer (Santa Clara, CA, USA). Fluorescence imaging was performed with Olympus FluoView Fv3000 laser scanning microscope (Tokyo, Japan).

The surface morphology of 3D FACs and 1D/3D PyPbI₃/FACs perovskite was characterized by using scanning electron microscopy (SEM, Regulus-8100, HITACHI, Tokyo, Japan) operating at 20 kV. The crystal structure was investigated by X-ray diffraction (XRD, DX2700, Dandong Kemait NDT C., Ltd, Liaoning, China) with a 2θ ranging from 5 to 37° in a step of 5° min⁻¹, using a monochromatic Cu Kα radiation source. Before the 3D FACs and 1D/3D PyPbI₃/FACs perovskite were exposed to gases, the XRD measurement was held on a glass substrate different from the deposited material on electrodes in order to avoid any interaction of sensing elements from the X-ray beam. The absorbance spectrum of the 3D FACs and PyPbI₃/FACs perovskite were measured by UV-visible spectroscopy (T9, PERSEE, Beijing, China) in the wavelength ranging from 400 to 870 nm on a quartz glass substrate. The photoluminescence (PL) spectrum of 3D FACs and 1D/3D PyPbI₃/FACs hybrid-structured perovskite were investigated with a Hitachi F-4600 spectrofluorometer, Tokyo, Japan.

The amount of the hydrogen product was analyzed by gas chromatography (Shimadzu GC-2014+AT 230C, TDX-01 column, TCD, argon carrier). UV-vis absorption spectra were recorded on a LAMBDA750 UV-vis spectrophotometer. FL spectra were taken on Hitachi F4600 spectrofluorometer. Transient absorption spectra were measured on the LP980 laser flash photolysis instrument (Edinburgh, UK). FL lifetime was performed by time-resolved confocal FL instrument (MicroTime 200, PicoQuant, Berlin, Germany). Photocatalytic experiments were conducted with 450 and 525 nm LED light (Zolix, MLED4) and 175 W Xenon lamp (LX-175, PEILC, Japan) with 420 nm filter. Electrochemical measurements were carried out on a CHI 760E electrochemical workstation at room temperature.

The fluorescence emission spectra shown in this paper were measured on a F4600 spectrofluorometer (Hitachi, Japan) with 380 nm excitation. FT-IR spectra and UV–vis spectra were respectively recorded on a FTIR-8400S spectrometer (Shimadzu, Japan) and WFN-203B spectrometer (Jingke, China). The transmission electron microscopic images (TEM) were measured by a JEM-2100 transmission electron microscope (JEOL, Japan). The size distribution of nanoparticles was determined by the Nicomp380ZLS dynamic light scattering technique (Santa Barbara, USA).

To assess whether the as-generated ROS species include hydroxyl radical, we performed similar fluorescence-based ROS detection assays but using p-phthalic acid (PTA) as the probe for hydroxyl radical^{33 (link)}. PTA is virtually non-fluorescent but, upon oxidation selectively by hydroxyl radical, becomes brightly green fluorescent (λ_ex/λ_em = 315 nm/320–600 nm). Specifically, PTA powder was dissolved in NaOH aqueous solution (0.2 M), to a PTA concentration of 50 mM. The resulting TPA solution was then mixed with a nanoparticle dispersion in PBS (at an expected mass concentration of nanoparticle) to a final mixture volume of 200 μL and a final TPA concentration of 500 μM, followed by incubation at 37 °C for 3 h. The resulting mixture was subsequently centrifuged at 8000 × g for 10 min to remove the nanoparticles, and the resulting supernatant was then subjected to fluorescence emission spectrum recording (λ_ex/λ_em = 315 nm/320–600 nm, with slit-widths of 5 and 10 nm for excitation and emission wavelengths, respectively) using a fluorimeter (F-4600 spectrofluorometer, Hitachi). Control is PTA in PBS-treated similarly but without any nanoparticle. Hydroxyl radical generation was indicated by the relative enhanced fluorescence intensity at 400 nm of a nanoparticle-containing dispersion compared to that of PTA in PBS. The reported results are averages of two independent trials.