D max 2500

Transmission electron microscopy (TEM; HitachiH7650, Hitachi) was used to record high resolution images at 200 keV. X‐ray diffraction (XRD) patterns were obtained with either a Rigaku D/Max‐2500 or an X′Pert PRO by PANalytical BV diffractometer using Cu Kα radiation (λ=1.5418 Å) at a scanning rate of 4.00° min⁻¹. Zeta potential measurements were carried out using a Malvern Instruments nanocomposite size analyzer (NanoZS, Worcestershire, UK). Fourier‐transform infrared (FT‐IR) spectra were obtained using a Thermo Scientific Nicolet iS50 FTIR spectrometer in ATR mode. UV‐vis spectroscopy was carried out using a Varian Cary 50 UV‐Vis spectrophotometer. Thermal gravimetry (TG) analysis (TG8120, Rigaku) was performed to estimate the quantity of the modifiers or molecules that attached on the surfaces of the TiO₂‐NH₃⁺ nanocrystals. 2.03 mg of the TiO₂‐NH₃⁺ nanocrystals were loaded for TG analysis. Temperature was maintained at 150 °C for 2 h for dehydration and then raised to 800 °C at the rate of 20 °C min⁻¹.